Maybe you've read that online, or a friend mentioned it. Either way, there's a low-level worry that when it comes to antibiotics, you've knocked your gut microbiome off balance, and you're not quite sure how to fix it.

Will your gut go back to normal?

Should you take probiotics?

And what else can you do?

After years of researching the gut microbiome (and a PhD in it) - here’s my take.

What we’ll cover today:

• What antibiotics do to your gut microbiome

• How long recovery really takes

• Should you take probiotics? And which type

• The practical guide: what to do before, during and after

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What antibiotics do to your gut

Before we get to the microbiome science, it’s important to say that antibiotics can be life-saving. If your doctor’s prescribed them, more often than not, they’re absolutely the right call. By not taking them, you could be putting your health (and as a result your gut microbiome too) at a much greater risk.

So what do antibiotics do? They help to fight off infections in your body by either killing off harmful bacteria, or preventing them from multiplying and spreading.

The problem for your gut microbiome is that antibiotics can't tell the difference between the bacteria making you ill and the “good” ones living in your gut, so both can take a hit.

A few things to note:

• Check you actually need them. Antibiotics don’t work on viral infections - the common cold, flu, and most coughs. If your GP hasn’t confirmed it’s bacterial, it’s worth asking.

• Ask whether there’s an option to wait. For some mild bacterial infections, your body may clear it on its own.

• If you do need them, take the full course at the prescribed dose. Stopping early is how antibiotic resistance develops, and it doesn’t protect your gut any more than finishing them does.

How long does your gut take to recover?

Within a couple of days of taking antibiotics, diversity drops, meaning you have fewer different types of bacteria than you did before. The bacteria that make short-chain fatty acids, molecules that support your immune system and gut lining, are often among the first to go. Some types of bacteria may not fully return, particularly after repeated or long courses.

For most people, their gut microbiome broadly recovers within a few weeks. For others though, it’s still not back to normal six months later. And a study published earlier this year on nearly 15,000 people, found that for some, differences still showed up four to eight years on.

How quickly you bounce back isn't quite as simple as which antibiotic or how long you took it for. Two people can take the same antibiotic for the same amount of time and have completely different recoveries.

Your starting microbiome, your diet, even your genetics can all come into it. Though some antibiotics do seem harder on the gut than others - but the research on exactly which ones is still catching up.

It’s worth saying that if your microbiome does look different after antibiotics, that doesn't automatically mean something has gone wrong.

Your gut microbiome is constantly changing, and while it might settle into a slightly different pattern than before, we don't consistently know that that's a problem in itself.

While we do have studies linking low microbiome diversity and antibiotic exposure with poorer health, cause and effect is hard to unpick - is it the microbiome change, or the infection itself, or the underlying health of someone who gets frequent infections? We don't fully know. So if you do have to take antibiotics, I don’t want you to panic that it’s game over.

Should you take probiotics?

Nine times out of ten, my answer is no.

But it does depend on what you’re taking them for.

Probiotics to “restore” your microbiome? That’s a no from me, at least for now.

No matter what the probiotic industry love to tell you, the evidence isn’t there yet to show they help. Before you say, well, can’t be any harm to it, one small study found that taking probiotics slowed microbiome recovery compared to doing nothing at all.

Where there is a stronger case is if you tend to get diarrhoea or an upset stomach during a course. Certain probiotics can help with that.

The two with the best evidence according to the 2023 World Gastroenterology Organisation guidelines:

• Lactobacillus rhamnosus GG ≥ 5 billion cfu per day, for the

  duration of antibiotic treatment

• Saccharomyces boulardii CNCM I-745, ≥ 5 billion cfu per day, for the

  duration of antibiotic treatment

So it comes back to what are you actually taking this for, and is there decent evidence that this specific type helps with that?

What to do instead?

The practical guide: before, during and after

If you know antibiotics are likely, for example you’re having surgery or you get recurring infections, start building your microbiome up in the week before.

The stronger your microbiome going in, the better position it’ll likely be in to recover.

During and after a course of antibiotics is when you especially want to make your gut microbiome a priority. It's more plastic than usual during this time, which means it may be more shaped by what you eat.

Eat more fibre

The most useful thing you can do before, during and after a course of antibiotics is eat more fibre.

Certain microbes are the best at kick-starting microbiome recovery - but to do that well they need fibre to feed on. By feeding on it, they make molecules that make your gut more welcoming for other types of bacteria. Without fibre, they struggle to get going and recovery may take longer.

People eating fibre after antibiotics got their short-chain fatty acid-producing bacteria back faster than those on fibre-free medical drinks. And in mice, those eating a high-fibre diet recovered their microbiome within a few weeks, while those on a Western-style diet (low-fibre, high-fat) still hadn't fully recovered nine weeks later.

Easy ways to eat more fibre:

Should you take a fibre supplement?

When upping your fibre, make fibre-rich foods the priority. Each food contains a variety of different fibre types, and comes packed with other nutrients and compounds that are good for your health too.

But if you're struggling to get enough through your diet (which most of us are) a fibre supplement can help close the gap.

Not all fibres are the same.

Look for ones that contain a variety of fermentable, prebiotic fibres, these are the types that feed your gut bacteria.

Good ones to look for are:

• Inulin

• Fructooligosaccharides (FOS)

• Partially hydrolysed guar gum (PHGG)

• Acacia fibre

A blend is better than a single fibre, different bacteria feed on different types. To give your gut time to adapt, start with a small amount and slowly build up over a few weeks. If you have IBS or a sensitive gut, look for PHGG or acacia fibre, they tend to be gentler on your gut than inulin or FOS.

Load up on fermented foods

Fermented foods are foods that have been transformed by bacteria and yeast, like kimchi, kefir, sauerkraut, live yoghurt, and miso.

They break down sugars in the food, which is what gives them that distinctive sour or tangy flavour, and it's also what makes them interesting for your gut.

In healthy people, a 2021 Stanford study found that eating plenty of fermented foods increased microbiome diversity and lowered 19 inflammatory markers.

Surprisingly, while there’s increased microbiome diversity, any new bacteria are unlikely to be from the fermented foods themselves. Instead, fermented foods seem to help make the gut, the home of your gut microbiome, more welcoming for other bacteria to move in and settle. Think less new tenants, more like getting the house ready for them.

• Make sure they're refrigerated. Fermented foods need to be kept cold to keep the bacteria alive. If it's sitting on a shelf at room temperature, it’s likely been heat-treated to make it shelf-stable (so the bacteria are dead) or it’s a pickled product.

• If you want to make your own, kefir is a great place to start. You buy the grains online, add them to milk, leave overnight, and strain. The grains are reusable so it works out much cheaper than buying it, and the variety of microbes in homemade kefir is often higher than commercial versions. It's also surprisingly easy once you've done it once or twice.

• Lots of ways to enjoy fermented foods! Try fermented vegetables on top of cheese and crackers, kimchi or sauerkraut stirred through brown rice, or a spoonful alongside eggs, noodles, or pretty much anything savoury at dinner. Kefir is great splashed into your morning fruit and yoghurt bowl, added to porridge, or whizzed into a salad dressing.

If someone you know is about to take a course of antibiotics, this might be worth sending their way.

Chat soon,

Emily xx

I’ve also recorded an audio walkthrough of this newsletter, in your inbox (just over 8 minutes).

With Fibre Power out three weeks ago, it’s been a bit of a chaotic whirlwind. Wonderful, and I’m so grateful, but also exhausting - less sleep, meals at odd times, three talks last week, and a book festival in Scotland this weekend.

So these are my tried and true go-tos, what I actually do to look after my energy on a day-to-day basis, and especially during the times when life gets a bit frantic.

What we’ll cover today:

• Three things to fix for a great night’s sleep

• Natural light and your body clock

• Caffeine timing - and the midday cut-off

• What to eat for sustained energy through the day

• For paid subscribers: a surprising chewing trick for a mental boost, nutrient deficiency that shows up as fatigue more often than people realise, and the energy tip that has nothing to do with food, sleep, or exercise

If you can’t sleep more, sleep better

When energy is low, sleep is almost always where to start. But we tend to fixate on hours, when quality matters just as much.

Poor sleep leaves you sluggish and fatigued, but there's a secondary effect too - it changes how and what you eat. It disrupts your hunger and fullness hormones, raising ghrelin (hunger hormone) and lowering leptin (fullness hormone), making you genuinely feel hungrier.

It also dials down the rational decision-making part of your brain around food and, at the same time, amplifies the part that flags high-calorie foods as urgent and hard to resist.

This isn’t a willpower problem, it’s biology in action.

• Wake up at a consistent time. Waking up at odd times through the week can disrupt your circadian rhythm, even when your total sleep hours are the same.

• Limit alcohol close to bed. You might find you fall asleep fine after a drink, but it can impact the quality and depth of your sleep, and how rested you feel. This effect gets stronger with age.

• Keep your bedroom cool. Your body needs to lose heat to help you drift off. This matters more as you get older, as the body becomes less able to regulate temperature during sleep. That could be opening a window at night, or swapping to a lighter duvet. Too cold also has its downsides. One study in older adults found the sweet spot to be around 20–25°C, but there seems to be genuine personal variation within this - so stick with the temperature that works best for you.

Can’t get more sleep? Try more light instead

If getting more or better sleep feels like a far-flung dream, then get outside into natural light, and specifically, let it reach your eyes.

Your master body clock receives light signals through photosensitive cells in your eyes, which send messages to the part of your brain that sets your internal body clock.

Getting enough natural light in the morning helps anchor your body clock to the right time of day, keeping you alert and focused - with a knock-on effect on sleep quality at night too.

If you hit an afternoon slump, getting outside can help, though morning is where light has the most powerful effect on your body clock.

Caffeine timing

Caffeine helps us feel more alert, but it can backfire if you drink it too late in the day.

Caffeine blocks adenosine, the neurotransmitter that builds up to make you feel sleepy. During the day that's great, keeping you alert and focused. But at night, you want that adenosine to accumulate so you drift off naturally, and caffeine can get in the way of that. Research shows caffeine taken even six hours before bed can reduce total sleep time by over an hour (but worth noting, the dose was equivalent to 3-5 cups of coffee!).

Caffeine has a long half-life, hanging around in your bloodstream for 3 to 5 hours, sometimes longer. It disrupts not just how long you sleep but how deeply - you might fall asleep fine, but wake up feeling groggy rather than rested.

A good cut-off time is midday. Enjoy your caffeinated coffee before lunch, then switch to decaf. Though how strict you need to be can depend on how sensitive you are to caffeine, everyone is different. I love my morning coffee, but I'm pretty strict about stopping at midday, because I really notice it in my sleep when I don't.

Kickstart the day with a high fibre and protein breakfast

Protein and fibre slow the release of sugar into your bloodstream, helping to steady your energy levels. It may also improve your memory in a small way - with any benefits likely to show up later in the morning, from 2 hours later. So if you’ve got a meeting or anything that needs your full attention mid-morning, what you eat first could matter more than you think.

Try these:

• Greek yoghurt with berries, mixed nuts and seeds, and a handful of granola or oats

• Parmesan scrambled eggs on rye bread with spinach and avocado

• Overnight oats with grated carrot, apple, raisins and nut butter

Read more

I realised that in the last year, I’ve stripped a lot of myself out of Second Brain. I wanted to give you the facts, and somehow thought the ‘me’ part got in the way of that.

But I was voice noting a talented friend who’s currently writing her first book - and telling her how deeply I believe it’s her voice, her perspective, that matters.

And yet, that’s exactly what I’d stopped doing myself.

I’d like to change that. And what with a new wave of Second Brainers here (hello! so wonderful to have you here), I thought why not say hi, hello, how are you. Whether you’ve been around since the early days, or freshly subscribed.

I’m grateful you’re here. And I’d love to get to know you better too (see below).

A little about me

I didn’t come into nutrition the way most people expect.

I was a chef first. I spent five years cooking professionally which gave me a front row seat to how people actually eat, what they enjoy, and what gets in the way.

I got the science bug. I re-trained as a dietitian, and then a PhD in nutrition and the gut microbiome soon followed - and I’m still at it. Right now our research team at King’s College London is running the EAT-FIBRE study.

I used to think feeling better meant cutting things out. I kept coming back to the word control, if I could only control what I ate, I could control how I felt. Perfect, black and white eating. Which was, excuse the pun, a recipe for disaster. The mental backlash of failure, the headspace it consumed, the energy it took. Just no.

Which is probably why I'm suspicious of any approach to nutrition that feels like punishment.

Why Second Brain?

It’s a nod to how brilliantly multi-faceted your gut really is, so much more than a digestive factory. How it reaches beyond digestion, influencing all areas of your body including your (first) brain.

Because that’s what health really is, it’s not just about warding off disease later in life, it’s how you feel right in the here and now too.

Eating well should give you back time and energy two fold. Physically, by supporting your body to feel its best, more energy, better mood, sharper focus.

And mentally, by being simple and clear enough that it doesn't eat into your headspace.

Because so much of what gets airtime in nutrition (the supplements, the protocols, the latest fix) is small, weak evidence, not worth your time or money.

I want to help you focus on the levers that actually move the needle, and let go of the rest.

So you can get on with the things that give you purpose and joy.

Subscribe now

What about you?

These take 30 seconds and they genuinely shape what I write. I’d love to know you and what you’re looking for.

A little more about me (since we’re here)

If you asked, I’d call myself a solar-powered extroverted introvert.

I can turn the dial up and be in my element with friends and family, but my true happy place is curled up on the sofa with my dog Mavis and a good book (fantasy or science fiction), or scaling a wild and windy hillside with a squished packed sandwich and tangerine at the top.

I travel a lot too, but more of the slow, spend time and absorb a place, type. Earlier this year I escaped London for three months of blissful sunshine and the cobbled streets of Lisbon.

I’d love to hear more about you in the comments below, how would you describe yourself?

Chat soon,

Emily xx

P.S. US subscribers, I hear that “xx” isn’t a thing in America? Is that true? In the UK it’s how we would end a text message or an email to a friend. An “x” is technically a kiss, but means love and care.

If you missed the episode, catch up here:

Ooph, it’s the hottest week of the year so far in the UK (hotter than Ibiza, would you believe). As much as us Brits love to complain about our usual grey clouds and drizzle, intense heat is something we just aren’t built for. With zero AC, my Victorian flat is doing its best impression of a greenhouse.

Three different people this week have asked me the same thing - should they be drinking electrolytes to stay hydrated in this hot weather?

Do you actually need them? Or is it marketing dressed up as science?

What we’ll cover today

• What electrolytes are and how they work

• Do you actually need to take them? Marketing vs reality

• Are they harmless?

• How best to stay hydrated in this heat

• Your DIY hydration drink recipe (paid subscribers)

What electrolytes are and how they work

Electrolytes are minerals that carry an electrical charge when they dissolve in your body's fluids - which is what lets your nerves fire and your muscles contract.

They’re also central to hydration, helping your body to hold on to water rather than letting it pass right through you.

• Sodium: Controls fluid balance and helps your nerves and muscles work.

• Potassium: Works with sodium to fire your nerves and keep your heartbeat steady.

• Magnesium: Helps your muscles relax (not just contract), and is involved in hundreds of different reactions in the body.

• Chloride: Works together with sodium to manage fluid, and helps keep your blood’s acid-base balance in check.

You lose a bit of all of these through sweat. The more you sweat, the more you lose, which is why you top them back up through what you eat and drink.

But essential doesn’t mean you need them by the sachet-ful.

Do you actually need to take electrolytes?

For most of us, no.

I’ve focused on the brands that suggest you take them daily for general hydration, rather than those marketed for post-exercise recovery. If you've run a half-marathon and sweated buckets, electrolytes become a different conversation.

When I looked at the labels, two things stood out:

• They're wildly inconsistent despite all being sold as daily hydration. Some barely contain any sodium and are more like flavoured vitamin water, while others are properly dosed but only useful when you've actually lost a lot (intense exercise, or an upset stomach).

• Most people don’t need them - you get enough from food, and most of the excess just gets peed out (sodium though is one to watch, and I’ll come to it below).

A slice of toast and a glass of milk gives you more sodium and potassium than the lighter, flavoured-water-style powders - at a fraction of the price. (The properly-dosed ones do pack in more sodium, which is exactly why they're not meant as an everyday drink).

The claims - true or false?

Marketing claims and fancy terminology can make electrolyte powders seem like a must have.

Here’s some of the main ones:

• “Better hydration”: Drinking plenty of water is what hydrates you. Unless you’ve lost a lot of electrolytes during intense exercise, or had an upset stomach, you don’t need extra.

• “More energy”: This is usually down to added B vitamins, which support energy metabolism. But unless you're deficient, topping them up won't make you feel more energetic. If you're tired all the time, the answer is almost never electrolytes, it's more likely sleep, food, your iron levels, or stress.

• “Better recovery post exercise”: After a long, sweaty session, replacing lost sodium and fluid genuinely helps. After a gentle class or a walk, you haven’t lost enough to need it.

• “Supports recovery from vomiting or diarrhoea”: Absolutely. When you’re ill, replacing lost fluid and electrolytes matters. But many of these aren’t dosed like a proper rehydration solution. If you’re genuinely unwell, a pharmacy sachet does the job better.

Is it harmless?

On average in the UK and the US, we are over-consuming salt, otherwise known as sodium chloride. It’s something I’ve written about before here:

Excess sodium pushes up blood pressure, which raises your risk of heart disease and stroke. So adding an extra daily dose on top of what you already eat (when you’re getting plenty as it is) is driving your sodium intake up even further.

Electrolyte solutions are not meant to be a daily habit.

The properly-dosed ones make sense when you’ve actually lost a lot of electrolytes, like after a hard sweaty session, or an upset stomach, and not as routine.

How best to stay hydrated in this heat

On a normal day, drinking plenty of water is best.

A study in the American Journal of Clinical Nutrition compared 13 drinks for how well they kept people hydrated - milk and oral rehydration solutions (the kind you get from a pharmacy) held water in the body better than plain water.

So if you’re worried about staying hydrated in this heatwave, you could have a glass of milk, or salted nuts with a glass of water alongside.

Milk contains sodium and potassium, but its protein and natural sugars help too. They slow digestion down, so the fluid is absorbed gradually rather than triggering a quick trip to the loo.

If you want the practical version - how to make your own electrolyte drink for heavy sweat days, or when you’re unwell - it’s in the paid version below.

Read more

Next Thursday, on the 21st May, my new book Fibre Power hits the shelves.

As we head into publication week next week, it’s time for something celebratory. And that calls for cake.

Like fibre, carrot cake is seen as a bit old fashioned. Yet somehow it doesn’t get treated with the same health glow as beetroot brownies or courgette muffins, even though it’s made with vegetables, nuts and spices.

So it feels very appropriate that, like fibre, it gets a bit of a revitalised image. Because honestly, both deserve a little rebranding.

This carrot cake recipe is very close to my heart. It’s based on an original recipe that my mother would bake for us, whether in square tin traybakes for childhood parties or tarted up for special occasions.

Over time, it became the carrot cake, the kind people remember. Friends asked me to make it for their wedding, and I later made it again for my brother and sister-in-law’s wedding too.

This is the Fibre Power-ed version.

It’s still rich, soft and properly decadent, but with a few fibre-boosting additions like spelt flour, flaxseeds, almond butter and pumpkin seeds - bringing it to 6g of fibre per slice.

One of the reasons I wrote Fibre Power was to show that eating more fibre is often simply about a few tweaks and additions, while still being genuinely delicious.

And of course, not everything you eat needs to be high fibre or ‘optimised’. Especially with celebration food, sometimes all that really matters is that it’s delicious and brings joy.

There’s room for both the classics and a few fibre-boosted favourites too.

Buy Fibre Power

And finally - if you’re in the UK, I’ll be speaking at a few events over the next couple of weeks, I’d love to see you there!

• Tuesday 19th May - Chorleywood Bookshop, Chorleywood

• Tuesday 2nd June - David’s Bookshop with Dominique Ludwig, Letchworth

• Sunday 7th June - Cheltenham Science Festival with Kenji Morimoto, Cheltenham

• Saturday 13th June - Borders Book Festival, Scotland

• Thursday 18th June - Toppings & Co., Bath

Chat soon,

Emily xx

And also wind. Gas. Farts. Parps. Whatever name you want to call being a bit fruity-tooty.

It’s a fair concern, but also misunderstood.

That’s why I wrote my book Fibre Power - a four week step-by-step plan with 60+ recipes. Making reaching 30g fibre easy and delicious - without feeling miserable from suddenly overloading your gut.

Often fibre isn’t the problem, it’s the way we are using it. Too much, too fast, and not giving our guts time to adapt.

What we’ll cover today:

• What bloating actually is

• Why fibre doesn’t always cause bloating

• 5 common fibre mistakes that’s making you feel worse

• How to increase fibre more comfortably if you’re prone to bloating

• List of high fibre, low FODMAP foods (paid subscribers only)

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What is bloating?

We often think of bloating as having a build-up of gas, but that’s not always true.

You may feel bloated without actually having excess gas. This can happen because the nerves in the gut are extra sensitive, so normal amounts of gas feel uncomfortable.

Sometimes the issue is also that gas is not moving through the gut properly, causing it to feel trapped and create pressure or fullness.

Bloating is also not always easily explained as caused by food.

There can be other factors like increased gut sensitivity, changes in the gut microbiome, constipation or slower digestion, and food intolerances.

A little gas is a good thing!

The goal isn’t to have no gas at all.

It’s to be able to have comfortable digestion, without excessive bloating, pain, or disruption to your day-to-day life.

Some bloating after meals can be completely normal, and is simply your digestive system physically filling and stretching as you eat and digest food.

A little bloating and gas can also often be a sign of a healthy gut, rather than a problematic one.

When your gut microbes feed on certain fibres, they make molecules for your health. And as they do that, they also make gas as a by-product. Some mild bloating and gas after increasing fibre simply reflects your gut microbes breaking fibre down.

Does fibre always = bloated?

Not as often as you may think.

Even in people with chronic bloating who avoided certain fibre-rich trigger foods, only about 1 in 5 actually showed a consistent reaction to those specific fibres when tested under controlled conditions.

Interestingly, that’s far fewer people than the researchers expected, suggesting that food triggers may be less predictable (and less universal) than we often assume. And this was in people with chronic bloating and possible food sensitivities, not the average healthy person.

When people did react though, the effect wasn’t subtle - bloating, discomfort and overall symptoms increased quite noticeably.

It was a small exploratory study, but it does raise the question, are we too quick to blame fibre for bloating?

5 common fibre mistakes that cause bloating

If you’ve been put off eating fibre after a bad experience, or are worried about increasing it because you’ve been warned by others about gas and bloating - here are 5 reasons why that might have happened, and what to do instead.

There’s so many benefits to eating more fibre, but how you go about eating more, especially at the beginning, really does matter.

1. Your gut didn’t have time to adapt

Your gut microbes adapt to the foods you regularly eat.

So if you suddenly go from very little fibre to lots of high fibre whole grains, beans, lentils, nuts and seeds overnight, your gut will likely struggle to keep up at first. And that’s where uncomfortable symptoms like bloating, excess wind, or changes in bowel habits can show up.

It’s a bit like starting exercise - you wouldn’t go from never running to attempting a marathon the next day. You’d build up gradually over time.

Your gut is similar. It often needs time to adapt to larger amounts of fibre.

As you eat more fibre regularly, the microbes that help break it down can start to grow in number and become more efficient at handling it. For many people, foods that initially caused bloating often become much easier to tolerate over time.

Try upping your fibre more gradually instead, aiming for around 3–5g more per day each week. For example, add just one extra high-fibre food or meal each day for a week before increasing again.

2. Too much fibre in one sitting

When you know you need to eat more fibre, it’s tempting to go all in straight away.

Suddenly swapping to ultra-high fibre products and foods may feel like you’re getting an extra head start towards your recommended 30g of fibre a day - but dumping a huge amount into one meal or snack can be a lot for your gut to handle if it’s not used to it.

Instead try this:

• Spread your fibre evenly across the day, rather than in one sitting.

• Avoid any recipes and products that have sky-high fibre numbers, at least until your gut has had time to adapt. Build up to around 10g of fibre per meal. That’s often much easier for your gut than trying to cram 25–30g into one meal.

3. Too much fermentable fibre at once

Different types of fibre can behave in different ways in your body.

Some fibres are broken down by your gut microbes (called fermentable fibres), while others aren’t fermented much - or at all.

If a fibre is highly fermentable, it means a fibre is quickly and easily broken down by your gut microbes. As they rapidly break it down, they can make more gas as a by-product, and faster.

When you’re not used to it, it can mean that suddenly eating a very large amount of certain high-fermentable fibre foods out of no-where, like beans and lentils, or jumping straight into a high-dose prebiotic supplement, can sometimes trigger uncomfortable bloating.

Instead, start low and go slow. If you’re new to beans, try having 1–2 tablespoons regularly to start with, and gradually build up over time.

4. Fibre without fluids can backfire

Some fibres work a bit like a sponge, absorbing water to help soften poo and keep things moving through your gut.

But if you up your fibre without drinking enough fluids alongside it, fibre can sometimes cause constipation, one of the biggest triggers for bloating. There isn’t enough water around, resulting in hard dry poos and trapped gas.

As a general guide, aim for at least 6–8 glasses of fluid a day, and potentially more if you’re very active, sweating a lot, or increasing fibre quite significantly. Water is great, but tea and coffee count too.

If constipation is something you struggle with, foods like kiwi fruit (2 a day) and prunes (8 a day) can help get things moving more comfortably.

5. It could be a FODMAP sensitivity

For some people, bloating goes beyond simply eating too much fibre too quickly, and may reflect a more significant sensitivity to certain foods. This is especially common in people with Irritable Bowel Syndrome.

FODMAPs are types of poorly absorbed sugars. Like some fibres, many FODMAPs are fermented by your gut microbes - but because they are smaller sugars, they are broken down much more quickly.

For most people, this is normal and healthy. But for others, this can cause gas to build up faster, alongside extra water being drawn into the bowel, and may trigger symptoms in FODMAP-sensitive people.

If this sounds familiar, it’s worth speaking to your doctor. Some people may benefit from trying a low-FODMAP diet, but this should be done with a low-FODMAP trained dietitian who can help identify your personal triggers and tolerance levels.

A low-FODMAP diet is not meant to be forever. It’s a short-term phase, followed by gradual reintroduction of foods. It’s important to know that a low FODMAP diet doesn’t mean no FODMAPs. Dose matters, and many people manage smaller amounts of high FODMAP foods fine without symptoms.

Even if you need to reduce certain FODMAPs, it’s still absolutely possible to eat enough fibre, it just often takes a little more planning.

High fibre, low FODMAP foods (serving size dependant):

Read more

The “30 plants a week” message is a good example.

It’s a gut health slogan you hear everywhere, so much so that it’s been called the new 5-a-day.

Yet when you look at the science behind it, it’s not nearly as strong as how it’s been communicated.

Yes, eating more plants is good for your health, but do we need to overbake study findings to encourage people to do so?

For the sake of a catchy phrase, it risks shifting focus away from what actually matters - simply getting enough plant foods in the first place.

What we’ll cover today:

• Where the “30 plants” idea comes from

• Why the data isn’t as precise as it sounds

• Why 30 isn’t a magic number

• What really matters, quantity or variety

Subscribe now

Where the “30 plants” idea comes from

The finding that 30 plants a week is linked to a more diverse (often considered a healthier) gut microbiome comes from the American Gut Project - a citizen science project where over 10,000 people shipped in their poo, alongside diet and lifestyle questionnaires, for scientists to analyse.

Its primary aim was to build a large, open microbiome dataset and understand how gut microbes vary across people and environments.

The ‘30 plants a week’ was actually a small sub-question inside this much larger project - one pattern among many and not the main focus of the study.

The dataset includes an impressively large number of people, but it’s worth noting that some of the comparisons behind this finding were based on relatively small groups (in some cases fewer than 90 people).

When they compared people eating very few plants (10 or less per week) to those eating a lot (more than 30), they saw differences in the gut microbiome.

People eating the most plant types tended to have:

• more diverse gut microbiome

• different types of microbes linked to fibre breakdown

• signs of more microbial activity in the gut

That all makes biological sense, and it’s supported by the wider research that a wider range of plants means a wider range of fibres and compounds feeding different microbes.

So while it supports the idea that variety matters, it doesn’t establish “30 plants” as a clear rule or optimal number. Let me explain why.

The data isn’t as concrete as it sounds

We all eat in very different ways.

And that can make collecting dietary data difficult, and time-intensive. Usually that means participants completing at least one day food diary, or a questionnaire on how often you ate 130 food items in the past month.

Nutrition-related findings based on a single survey question, tend to be treated with more caution.

The participants were asked one question:

"In an average week, how many different plants do you eat?

a. <5

b. 6-10

c. 11-20

d. 21-30

e. >30

e.g. If you consume a can of soup that contains carrots, potatoes, and onion, you can count this as 3 different plants; If you consume multi-grain bread, each different grain counts as a plant. Include all fruits in the total.”

• You need to remember how many plants across the entire week (unless you have a photographic memory, that’s hard)

• Mixed meals are hard to break down accurately

• Quantity wasn’t captured - even smidges counted, like spices and herbs

• Quality wasn’t captured - foods made with refined plant ingredients still count e.g. biscuits, cake, and crisps

• Leaves room for interpretation around what counts as one plant (e.g. individual spices?)

It gives a rough idea of plant diversity (the number of different types of plants) but it’s too messy to give a precise number.

The number 30

The optimum number of plants wasn’t something researchers set out to test.

Instead, they compared people at the extremes - those eating very few plants (around 10 or less per week) versus those eating a lot (more than 30), leaving everyone out in the middle.

That’s a common approach in this type of research, comparing the lowest with the highest makes any differences easier to spot.

But it also means the cut-offs (like “30”) aren’t special, they’re just where the researchers happened to draw the line. It could just as easily have been 25, or 35.

That’s useful for finding patterns, but it means there’s nothing especially magical about 30.

Hard to separate cause and effect

People eating 30+ plants per week aren’t just different in one way.

They tend to eat more fibre, their overall diet is usually better, and they’re often more health-conscious full stop.

In research, we try to separate that out - adjust for things like fibre or overall diet quality to see what’s actually doing the heavy lifting.

The study used statistical methods to explore these patterns, but it wasn’t able to fully adjust for everything that tends to come with eating more plants.

So when differences show up in the gut microbiome, it’s hard to know what’s actually behind it.

Where’s the harm?

Encouraging people to eat a wider range of plants is in no way a bad thing.

But when we overemphasise the evidence behind “30 plants a week”, it risks making the science sound more precise and certain than it really is.

Life is busy. Making changes for your health can be hard. Wouldn’t you rather know that your efforts are backed by strong evidence?

Or that you can make it work for your lifestyle without needing to hit a specific number, because the evidence for that just isn’t there?

I don’t think we need to stop saying “30 plants a week”. It just needs more nuance and context, so it becomes a flexible guide rather than an inflexible target.

We’re often quick to call out influencers for overstating evidence - we shouldn’t do the same, even if the overall direction of the message is right.

Yes, plant diversity still matters (in a way that works for you)

Eating a wider range of plant foods is still a good thing – different plants provide different fibres and compounds, and that supports a healthy gut.

Though you still need to be eating enough total plant foods in the first place.

A few practical ways to approach it:

• Focus on getting the basics right first: aim to include plant foods in most meals before worrying about variety

• Build variety gradually: add one or two new plant foods each week rather than chasing a specific number

• Rotate what you already eat: switching between different fruits, veg, grains, nuts or beans still counts

• Think beyond fruit and veg: herbs, spices, beans, lentils, whole grains and nuts all add to variety

• Prioritise what’s realistic for you: consistency matters more than hitting a target, eating in a way that tastes good - that you enjoy

• Remember quantity still matters: a varied diet is helpful, but only if you’re eating enough plants overall

Chat soon,

Emily xx

And while yes, we absolutely do want to take care of the collection of microbes nestled in our guts, we’re often told we need this supplement and that probiotic (usually at huge expense) to do so.

Couple that with headlines like “10 worst foods for your gut health”, and it can quickly start to feel overwhelming - like you have to get everything exactly right, all of the time.

That’s one of the reasons I’m so pleased that Registered Nutritionist Sophie Gastman (RNutr, Public Health) has joined us here on Substack with her newsletter - P for Pleasure - which I highly recommend subscribing to if you’re not already.

Subscribe to A Dose of Vitamin P

Her work focuses on cutting through the noise of nutrition advice, and helping people build a more flexible, realistic relationship with food.

You may already know Sophie from her mouth-watering recipes on Instagram (@sophiethenutritionist). She also has a fantastic book Find Your Healthy: 100 delicious recipes with a side of science out tomorrow (23rd April, in the UK).

We met last month at the Gut Microbiota for Health conference in Porto, and I immediately knew I wanted to ask her to write something for Second Brain.

Over to you Sophie…

It’s becoming difficult to ignore the noise around gut health. It’s in our newsfeeds, our podcasts, and has even crept into the office chit chat.

And while looking after your gut is clearly important for long-term health, at what point does it become counterproductive?

Our understanding of the gut microbiome has grown rapidly and has undoubtedly been one of the most significant shifts in public health over the last decade. We know more than ever about fibre, plant diversity, and the role our gut bacteria play - but ironically, knowing more hasn’t necessarily made eating any easier. In fact, for many, it’s made it significantly more stressful.

Welcome to the era of optimisation

As a culture, we have a knack for turning sensible health advice into unforgiving, binary rules.

In the past, that looked like Atkins, SlimFast, or your mum heading off to Weight Watchers. Nowadays, it looks a bit different, but the underlying mindset isn’t miles off.

It’s no longer enough to just eat your five-a-day; we must now eat exactly 30 plants a week.

It’s no longer enough to be more intentional about gently increasing your fibre intake; we must be fibremaxxing at every meal.

It’s no longer enough to simply increase variety; we must own a lineup of expensive probiotic powders and pills (whether they’re doing anything meaningful is another question entirely).

Individually, none of this advice is inherently wrong, and it isn’t necessarily harmful either. We know that fibre is beneficial, plant diversity does matter, and the gut microbiome plays an important role in health. However, how this advice is being applied is worth questioning. At the point where eating becomes solely about hitting targets or doing everything perfectly, it stops being healthy.

This might look like:

• Feeling like every single meal needs to be “good enough” for your gut without any room for flexibility

• Obsessing about adding fibre to everything, whether you actually want it or not

• Stressing over tracking and hitting an arbitrary number* of plants each week

Again, these behaviours might not be problematic on their own, but it’s important to notice when they become extreme or start to be the source of anxiety around food.

* The “30 plants a week” idea comes from the American Gut Project - a study that found people who ate 30 types of plant foods tended to have a more diverse gut microbiome than those eating 10 or less. However, they didn’t test lower numbers in a way that lets us know exactly where benefits begin, so it’s entirely possible that people would see benefits at fewer than 30 plants a week.

Joining the dots to the gut-brain axis

It’s all well and good hitting every gut health goal under the sun, but if you’re significantly stressed about doing so, you may be undermining the very thing you’re trying to support without realising.

Many of us have heard of the gut-brain axis. We know, at least in theory, that what’s happening in our minds can directly affect what’s happening in our gut (and vice versa). Yet, I’ll bet a lot of us still consistently let stress management fall to the bottom of the list when it comes to looking after our gut health.

The gut and the brain are in constant conversation. When you are anxious - perhaps because you’re stressing over whether your lunch has enough diversity - your gut will know about it. Stress can alter motility, increase sensitivity, and trigger the bloating or discomfort you’re trying so desperately to “fix”.

It’s a classic Catch-22 situation. You focus on perfecting your diet to heal your gut, that focus creates pressure, the pressure triggers symptoms, the symptoms make you think you need even tighter control, and round it goes.

Isn’t food more than just fuel?

Another “side effect” of trying to be perfect in the way we eat is that it’s surprisingly easy for food to become something we think about more than something we actually enjoy.

This is the kind of mindset that creeps in gradually, and before you know it, the background noise of constantly thinking about your food choices starts taking up more headspace than you realise.

And the impact of that isn’t limited to how enjoyable eating feels. When food becomes something you’re constantly managing, it can start affecting other parts of your life too. For example, social occasions, like eating out, become a trigger of anxiety and make you feel isolated. Even day-to-day flexibility like grabbing something on the go can start to feel harder than it needs to be.

This often stems from a place of trying to do the right thing for your health, which is why it’s important to recognise that eating gives us so much more than just nutrients. It also gives us enjoyment, comfort, routine, and a way to connect with other people and our culture. It’s part of what I like to call “Vitamin P” (P for pleasure), and it’s often left out of the conversation when it comes to supporting our health.

When we ignore that side of food, eating can start to feel more stressful and far less sustainable. At the end of the day, if a meal is nutritionally “perfect” but eaten in a state of resentment or joyless obligation, is it really doing you any good?

So what does supporting your gut actually look like?

To be clear, I’m not dismissing gut health or suggesting we bin the fibre. Most of us in the UK aren’t getting enough and would benefit from eating more. However, I am suggesting we widen the definition of what “healthy” looks like so that it includes a bit of flexibility and joy as well.

Nutrition rarely works in such black-and-white terms. You can care about fibre and still eat foods you enjoy, you can aim for more variety without overcomplicating every meal, and you don’t need to get it “right” 100% of the time for it to be worthwhile.

On that note, here are some of my top tips to support your gut in a much simpler, less extreme way:

• Aim for variety over time: Remember to zoom out and look at your diet as a whole - you don’t need to get it perfect every single day of the year.

• Do the simple things first: Often, the simplest things, like staying hydrated and eating at regular intervals, do more for your digestion than a fancy supplement ever could.

• The ‘good enough’ rule: Use targets like “30 plants a week” as loose inspiration. If you hit 22, you’re still doing brilliantly.

• Gentle, intentional additions: Always focus on “adding”, not “subtracting”. Add some avocado to your eggs on toast (did you know ½ an avocado has almost 5g of fibre?) or swap to a seeded loaf. You don’t need to force yourself into having a completely different meal you don’t enjoy in the name of hitting your fibre target.

• Be flexible: Some days involve travel, busy schedules, or eating whatever’s available at a party. These days might be lower in fibre than others, and that’s ok. The occasional day of beige eating isn’t going to set you back very far.

Remember, the gut is remarkably adaptable, and a calmer, more flexible approach to eating is usually more gut-friendly than perfectionism.

Finding Your Version of Healthy

Ultimately, looking after your gut isn’t about being perfect or partaking in obsessive behaviours. It’s about finding a comfortable balance where you can be intentional with what you’re eating, whilst still making room for moments of joy and pleasure.

If you’ve realised that your pursuit of health is taking up a disproportionate amount of mental energy, you’re probably already doing more right than you think.

And if you’re ready to reclaim some of that headspace, my book Find Your Healthy, is designed to help you do exactly that. It moves away from rigid rules and back towards an evidence-based, flexible way of eating that actually works in real life. Think of it as a toolkit for finding what your own version of healthy looks like - complete with 100 recipes that prove you don’t have to choose between “being healthy” and a meal you actually want to eat.

Thanks so much Sophie!

I hope you enjoyed this as much as I did, I think Sophie captures something so important here.

A lovely reminder that looking after your health doesn’t have to come at the expense of enjoying your life.

Chat soon,

Emily xx

It’s no longer just a disease of people in their 70s. More younger people are now being affected - cases in those under 50 years old have nearly doubled worldwide between 1990 and 2021.

And this isn’t just happening in one place.

Across 19 countries, rates are rising in younger adults, while in almost half of them, rates in older adults are staying the same or even falling.

The problem is, we don’t fully understand why. And that’s worrying, because if we don’t know the cause, it becomes much harder to prevent.

Here’s what we know so far - and 7 tips linked to lower risk of bowel cancer at any age.

What we’ll cover today:

• Is it the same disease?

• Why rates in young people may be rising

• What key warning signs to look out for

• 7 ways to lower your risk - no matter your age

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Is it the same disease?

Bowel cancer in younger people isn’t just the same cancer earlier.

It doesn’t always look and behave in quite the same way.

In people under 50 years old vs. seniors:

• It shows up in different parts of the bowel. Tumours are more common in the left side of the lower intestine (colon) and the rectum.

• It can behave more aggressively, that isn’t fully explained by the fact that younger patients are often diagnosed later, sometimes because symptoms are missed or brushed off.

• There are also early signs that the cancer itself may be slightly different at a biological level - for example, the genetic changes inside the tumour don’t always match what we typically see in older adults.

Why younger people?

The most honest answer is that we don’t fully know yet.

Each generation seems to be at higher risk than the one before it - at the same age.

Across countries like Australia, Canada, England and the US, people born in the 1990s are facing at least 4 times the risk of bowel cancer compared to those born in the 1960s.

There’s a strong signal that there’s something new in the way that we’re living, that’s driving this rise.

This could be due to:

• A shift in how we eat: It’s not that every part of our diet is worse - but some key patterns have shifted in ways that may affect gut health - we tend to eat less fibre and more processed, ready-made foods.

• Obesity: Carrying extra body fat (especially around your waist) can put your body into a low-level state of inflammation and affect hormones like insulin. Over time, this may make it easier for cancer cells to grow in the bowel.

• Taking antibiotics when you’re young: Antibiotics can disrupt your gut microbiome, especially when you’re younger - a time when your gut is still developing and more easily affected. This may have longer-term effects on gut health and cancer risk.

• Microplastics: Tiny plastic particles are now being found in our food, water, and even human tissues - including bowel cancer tumour samples. They may be affecting the gut lining, inflammation, and the microbiome.

What links many of these factors together is the gut microbiome, the trillions of microbes living in your gut.

When this balance is disrupted, it may create conditions where bowel cancer is more likely to develop over time.

Yet rates are falling in older adults…

In many countries, the opposite trend is happening for older adults - bowel cancer rates in people over 50 are actually falling or staying stable.

A big part of this is thanks to earlier detection and prevention.

Tests like bowel screening kits and colonoscopies can catch early changes, and even remove pre-cancerous polyps before they turn into cancer.

There’s also been a gradual shift in some risk factors over time, like less smoking and more awareness around diet and health.

What warning signs should you look out for?

A simple way to remember is BOWEL:

B - Blood
Blood in your poo or on the toilet paper.

O - Ongoing changes
Changes in your bowel habits that don’t go away, like diarrhoea, constipation, or thin/ribbon-like poos.

W - Weight loss
Losing weight without trying, and without explanation.

E - Extreme tiredness
Feeling unusually tired all the time, or being told you’re low in iron (anaemia).

L - Lump or pain
A lump, discomfort, or ongoing pain in your stomach or bum.

If any of these last for three weeks or more, it’s worth getting checked.

7 simple ways to lower your risk (no matter your age)

1. Eat more fibre: Every extra 10g of fibre per day is linked to around a 10% lower risk of bowel cancer, likely because fibre feeds your gut microbes and helps move waste through your gut more quickly. Wholegrains in particular seem especially protective.

2. Get enough calcium (and dairy): Calcium, especially from dairy foods like milk, yogurt and cheese, has been linked to a lower risk of bowel cancer. It may help by binding harmful substances in the gut.

3. Cut back on red and processed meat: Processed meat (like bacon, sausages and deli meats) is classified as a Group 1 carcinogen, meaning there is strong evidence it can cause cancer. Red meat is classed as probably carcinogenic.

4. Limit alcohol (and binge-drinking): Alcohol and bowel cancer risk are closely linked, and the risk goes up the more you drink over time. Even moderate drinking can have an effect, so it’s worth being mindful. Some early research suggests that binge drinking at a younger age may be linked to rising rates, but we don’t fully understand this yet.

5. Avoid smoking: Most people associate being a smoker with lung cancer, but it’s also linked to bowel cancer. Another good reason to quit if you can.

6. Be cautious with unnecessary antibiotics: Antibiotics are important when you need them, but they can also disrupt the balance of microbes in your gut.
   Some studies suggest frequent use may be linked to higher colon cancer risk - though we’re still learning more about this.

7. Don’t ignore vitamin D: Low vitamin D levels have been linked to a higher risk of bowel cancer. Depending on where you live, that might mean getting enough sunlight, or taking supplements.

Chat soon,

Emily xx

Alongside the endless runny noses, it’s not all bad news.

Being in nursery exposes babies to new microbes and may help shape their gut microbiome.

A recent study found that after just three months at nursery, babies shared around a quarter of their gut microbes with other babies.

What we’ll cover today:

• How a baby’s microbiome starts at birth

• Why early childhood is a key window for gut development

• What happens to the microbiome at nursery

• How everyday contact (at home and with others) shapes it

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Baby’s first microbes

A baby’s microbiome starts taking shape at birth.

In the womb, their gut is mostly untouched by microbes, so that first exposure during delivery kick-starts their microbiome - like a microbial big bang.

Babies born vaginally are coated in microbes from their mother, while those born by C-section tend to pick up more from hospital surfaces, and the skin of people around them.

These microbes start to settle, especially in the gut, where they begin to grow. At the start, there are only a few types of gut bacteria (types of microbes), but this changes quickly.

Over the first few days, weeks, and months, this community starts to build.

While birth is an important starting point, it’s really just the beginning.

Crawling, grabbing and playing together

In a recent study, researchers followed 43 babies (around the age of 10 months old) through their first year at nursery.

They found that microbes were regularly being passed between them - likely through shared toys, surfaces, and close contact.

And this happened quickly.

By the end of just the first term, around 28% of tracked gut microbes were shared with other babies, compared to about 20% shared with their own family.

We don’t yet know what this microbe sharing means for long-term health - but it suggests how important everyday interactions may be for shaping the gut microbiome.

Growing guts

In the early years, a child’s microbiome is still finding its feet.

In the first few years of life, it rapidly changes - shaped by what they eat, where they spend time, and all the little things they touch and put in their mouths.

Because it’s still developing, it may be more influenced by these everyday experiences, which is why early childhood is often seen as an important window for supporting gut health.

Over time, the mix of gut microbes gradually becomes more varied and starts to look more like an adult’s, settling into a more stable, adult-like microbiome by around 3-5 years old.

Living together

This idea of sharing microbes doesn’t just happen at nursery.

Research shows that people who live together can share up to nearly 14% of the microbes in their gut. But even people who don’t live together, and simply spend a lot of time together, can share around 8%.

That’s likely down to small, regular contact - sharing spaces, touching the same things, eating together, and even things like greeting with a kiss on the cheek (or close intimacy between partners).

For babies, this means microbes don’t just come from one place. They’re picked up from parents, siblings, other children, and the spaces they spend time in.

It’s another reminder that building a healthy microbiome isn’t about one perfect habit, but about the little everyday moments that add up over time.

Chat soon,

Emily xx

Small, everyday signals that you may not be paying attention to - and are easy to ignore.

But they’re often the earliest signs of how your body is functioning beneath the surface, reflecting underlying systems like hydration, digestion, the nervous system, and hormones.

Learning how to read these signals and notice patterns can help you spot changes early and respond sooner.

Whether it’s simply optimising how you feel, or catching new subtle warning signs, paying attention to your body is one of the most important things you can do.

What we’ll cover today:

• How to read your body’s signals (and why patterns matter)

• Simple signs to check in on day to day

• What changes might mean, and when to pay attention

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What to look for - patterns

Most of these signals don’t mean much as a single occasion.

That’s because your body naturally fluctuates day to day, so an occasional off day isn’t usually something to be concerned about - we aren’t looking for perfect.

What’s more meaningful is your average over time, your regular pattern.

Focus on what is normal for you (and not someone else). That’s because sometimes there can be a wide range between people in what’s considered healthy.

That means paying attention to:

• your usual pattern over time

• any consistent changes away from that, and whether there’s a clear reason for the shift

It’s always best not to self-diagnose, and see your doctor if you’re worried.

Pee colour

Your pee colour is one of the easiest ways to check your hydration.

It reflects how your kidneys are balancing fluids in your body. When you haven’t had enough to drink, your body holds onto water, making your pee a darker colour. When you’re well hydrated, the colour becomes lighter.

What to look for:

Read more

Poo transplants, formally known as faecal microbiota transplantation (FMT), involves transferring processed poo from a healthy donor into the gut of someone with certain serious illnesses.

It’s not about the waste itself, but the trillions of microbes living inside it.

Read on for more on poo transplants - how they work, who they’re for, and what the future may hold - should we be banking our healthiest poos for later life?

What we’ll cover today:

• What a poo transplant actually is

• The conditions it’s currently used for

• How donors are screened (yes, very carefully)

• Are you a ‘super’ donor?

• Should we bank our healthy poos?

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What is a poo transplant?

A poo transplant - formally called faecal microbiota transplantation (FMT) - is a medical treatment where poo from a carefully screened healthy donor is processed and transferred into the gut of someone who is unwell.

Why poo? Because it’s packed with microbes that live in your gut and are naturally shed into poo as waste moves through your digestive system.

The aim is to help restore balance to the gut microbiome of the person being treated, which in turn may improve symptoms and support recovery.

FMT is a relatively new area of medicine - the first high-quality clinical trial was published in 2013, and clinical guidelines have supported its use for certain illnesses since 2018.

It’s an evolving field, but one with potential, as scientists continue to explore how reshaping the gut microbiome could influence health and disease.

What conditions is it used for

Right now, poo transplants are mainly used for one condition - Clostridioides difficile (C. diff) infection - particularly when antibiotics aren’t stopping it from coming back.

C. diff is a type of harmful bacteria that causes severe diarrhoea and stomach pain, and in some cases it can become very serious - leading to dehydration, kidney problems, or even life-threatening complications.

Current guidelines recommend FMT for people with repeated or hard-to-treat C. diff. It’s thought to work by restoring helpful microbes and helping the gut rebuild its natural defences.

There’s growing interest in whether FMT could help in inflammatory bowel disease, irritable bowel syndrome, and even potentially other conditions where the gut microbiome is involved.

But outside of C. diff, the evidence isn’t strong enough yet. For now, UK and US guidelines suggest that any use in other conditions is limited to clinical trials.

Donor screening: who’s poo is “good” poo?

Donor screening is one of the most important, and challenging, parts of poo transplants.

The main aim is safety. Doctors need to make sure they’re not passing on infections such as hepatitis, HIV, antibiotic-resistant bacteria, or gut pathogens like Salmonella or E. coli.

Screening is also designed to avoid donors with medical conditions that could potentially affect the gut microbiome, such as autoimmune, metabolic, or neurological diseases.

Potential donors undergo detailed health and travel questionnaires, plus extensive blood and poo testing - often stricter than blood donation - and are regularly reassessed to ensure ongoing safety.

Finding suitable donors isn’t easy, one recent study found that only 1.7% of volunteers actually qualified, and nearly 39% dropped out before screening was even completed because the process is so long and demanding.

Safety is taken seriously, is tightly regulated medical treatment - not something to try at home.

Are you a ‘super donor’?

In some studies, researchers noticed that poo transplants from certain donors seemed to work especially well - these people are sometimes nicknamed ‘super donors’.

Read more

We’re told to cut back because of links with blood pressure and heart disease.

Yet you’ll also hear claims that this advice is outdated, and that eating too little salt could be harmful.

Add in studies that seem to point in different directions, and it’s no wonder people feel unsure.

So does how much salt you eat actually matter?

What we’ll cover today:

• Why we keep arguing about salt

• How some studies get misread

• Where potassium helps - and where it doesn’t

• How to think about salt day to day

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Salt vs. sodium

Salt comes from underground deposits or from seawater that’s evaporated to leave salt crystals behind.

What we know as table salt, is actually sodium chloride, a compound made up of sodium and chloride.

Sodium helps regulate fluid balance and allows nerves and muscles to work properly. Chloride also supports fluid balance and is needed to make stomach acid for digestion. Both are essential, but it’s the sodium part of salt that’s most closely linked to blood pressure.

That’s why advice focuses on how much salt we eat overall. In the UK, it’s recommended to eat no more than about 6g a day of salt (around 1 level teaspoon, equal to about 2400mg of sodium). That includes the salt already present in food, as well as the salt we add in cooking.

On average though, we’re eating over this - closer to 8–9g a day.

Most of the sodium we eat comes from everyday foods like bread, cheese, cereals, sauces and ready meals, rather than what we add when cooking at home. Sodium is also found naturally in fruit and vegetables, but usually in very small amounts.

Salt and blood pressure

When we eat too much sodium, the body keeps more water, which increases the pressure inside blood vessels. Over time, this puts extra strain on the heart and circulatory system.

That’s why raised blood pressure is one of the strongest risk factors for heart disease and stroke.

It’s especially dangerous because many people don’t realise they have blood pressure problems until it’s picked up during a routine check, and why it’s often called a silent killer.

In the US, heart and circulatory disease is the leading cause of death, and the second main cause of death in the UK.

That’s why salt is taken seriously in public health advice.

In people with high blood pressure, salt reduction has a clear and meaningful effect. In people with normal blood pressure, the average drop is smaller, but it still moves in the right direction.

Some people are more sensitive to salt than others because of factors like age, genetics or existing blood pressure. Around one in three healthy adults are classed as salt sensitive, rising to over half of people with high blood pressure, and it becomes more common as we get older. But it isn’t an on–off switch. Even people who aren’t labelled salt sensitive usually still see their blood pressure go up, but less dramatically, when eating too much salt.

The J-curve confusion

You may have heard that too little sodium is also bad for your health.

That idea mainly comes from a few large population studies, like the PURE study. These types of studies don’t change what people eat, instead they look for patterns in large groups of people, like the links between estimated sodium and risk factors or disease.

In the PURE study, they found that people who ate a lot of sodium were more at risk, mainly in people with high blood pressure. But the risk also appeared to be higher for the people who were estimated to have eaten the least sodium, too. When you plot that on a graph, it forms a J shape - with risk rising at both ends.

That can sound worrying. But there are two main reasons this pattern can be misleading:

• Sodium wasn’t measured directly.
  Many population studies estimate sodium from a single spot urine sample because it’s easier than a full 24-hour collection. But sodium levels change a lot during the day, so people can easily be misclassified - especially at the low end.

• Reverse causation
  People who are unwell, tend to eat less and be advised to cut back on sodium, and are then more likely to fall into the lower sodium group. That can make lower sodium look risky, even when it isn’t the cause.

What about the rise in stress hormones you sometimes hear about?

There’s a worry that cutting salt may push up your stress hormones. When salt is cut suddenly, your body can briefly switch on hormones like adrenaline and noradrenaline to keep blood volume and blood pressure stable. That response is normal and protective, similar to what happens with dehydration or standing up quickly. And it settles.

In longer studies of four weeks or more, including studies where sodium was dropped to around or below 2000mg a day (<5g salt), those hormones, cholesterol and kidney markers looked no different, while blood pressure is lower.

Intervention studies often matter more

Population studies can spot patterns, but they can’t tell us what’s causing what.

Intervention studies are clearer - researchers deliberately change how much sodium people eat and are able to closely track to see what happens.

In the DASH–Sodium trial, adults with and without high blood pressure were assigned one of two diets, then randomly cycled through high, medium and low levels of sodium, down to about 1,500mg of sodium a day (about 2/3 teaspoon of salt). Sodium was checked using 24-hour urine collections.

As sodium went down, blood pressure went down too, in people with and without high blood pressure, with the biggest drop at the lowest sodium level. Stepwise, and no J-curve.

That’s why well-run trials often carry more weight than patterns from population studies.

Potassium and sodium: why balance matters

Potassium is another electrolyte, but it works differently from sodium. It can help the body get rid of excess sodium through the kidneys and relax blood vessels. While it doesn’t cancel out sodium, it softens some of sodium’s effects on blood pressure.

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Not how to eliminate it (that’s not realistic), but how to respond to stress better when it shows up.

The Add-Ins for Your Health series is built on one simple idea:

Health sticks better when you add things in, one step at a time, rather than cutting things out, or trying to overhaul everything at once.

If you missed the beginning of the series, you can catch up here:

That’s where you’ll find the personal daily habit checklist and the weekly “How do you feel?” tracker as downloadable PDFs, the tools we’ll use throughout the six-week series.

So far we’ve covered Week 1: Fibre, Week 2: Protein, Week 3: Movement, Week 4: Sleep.

Week 5: Stress

A little stress is no bad thing

Not all stress is harmful. In small doses, it may actually help.

This is the kind of stress you might feel before:

• giving a presentation at work

• sitting an exam or test

• having a difficult conversation

• doing something slightly outside your comfort zone

In these moments, your body switches on the stress response temporarily. Your brain releases stress hormones like adrenaline and cortisol, which:

• sharpen focus and attention

• increase alertness

• mobilise energy so you can perform

Afterwards, your nervous system settles back down.

Heart rate slows, breathing eases, hormones return back to baseline. This rise-and-fall is normal, healthy, and helpful in scenarios where you need to perform.

In one study, men were put through a short, stressful task or a calm one, then tested on concentration before and after. Those who experienced stress actually concentrated better afterwards than those who didn’t.

The people who focused better were the ones who felt a bit more on edge, but didn’t have a big cortisol spike. So a small dose of stress may sharpen concentration, but too much could tip it the other way.

When stress becomes a problem

The issue often isn’t stress itself, it’s long-term stress without recovery.

Chronic stress happens when your body stays in high alert mode for days, weeks or months, with little chance to switch off.

This can happen when stresses are ongoing or feel inescapable, like:

• constant work pressure

• caregiving responsibilities

• financial uncertainty

• health worries

• poor sleep layered on top of everything else

The stress response is activated again and again, but the body doesn’t fully return to baseline.

It’s this lack of recovery that is linked to health problems like poorer sleep, low mood and anxiety, changes in appetite, gut symptoms, higher blood pressure, and over time, a greater risk of heart and metabolic disease.

Stress needs recovery

Let’s be realistic here, most of the time we can’t avoid stress.

Instead, think about how to help your body to recover from stress, with ways to manage your stress response so that your body settles back to baseline.

That’s what the de-stress add-ins this week are designed to do, not remove stress from your life, but help your nervous system recover more often.

Pick your de-stress add-in to start this week

Choose one new de-stress add-in to start this week and keep it going.

Write it into your habit checklist (if you missed this, you can find it in the series kick-off post). Aim for most days, not perfection.

5 ways to ease stress (and a science-backed music track)

1. Use a breathing technique to ground yourself

   Breathwork seems most useful as a regular practice that lowers day-to-day stress - and it can also be used in the moment, either to steady yourself before something stressful or to help you come down afterwards.

   Slow, steady breathing helps signal to the body that it’s safe to settle, making it easier to come back to baseline after stress.

   

   3 Simple Breathing Hacks For Instant Calm Dr Emily Leeming

   1.28MB ∙ PDF file

   Download

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2. An hour’s walk in nature

   An interesting brain-imaging study looked at what happens after a one hour walk in nature vs. along a busy city street. Researchers scanned people’s brains before and after the walk, then measured how they responded to stress-related tasks.

   After the nature walk, activity in the amygdala - a key stress and threat centre in the brain - went down. After the city walk, it didn’t change.

   Just an hour in a nature seemed to calm the brain’s stress response.

3. Even simply imagining nature can help ease stress

   After a stressful maths task, students spent just five minutes imagining either nature (things like forests, rivers or birdsong) or urban scenes (roads, buses, shopping centres). Imagining nature left them feeling more restored, with small but meaningful signs of relaxation in the body, like a slower heart rate.

   If you can’t get outside, even pausing for a few minutes to picture a calm natural scene - or listen to nature sounds and let your mind wander there - may help your body start to settle.

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