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Microbiome Myths and How to Help Your Digestion

Microbiome Myths and How to Help Your Digestion

Laura Thomas, PhD


Laura Thomas will be speaking on the ‘Nutrition and Nutribollocks’ panel at the HBC Summit on 15th April with Pixie Turner, Dr Rupy Aujla and Anthony Warner. Get your tickets here.

Gut health is like so on trend right now, with everyone trying to get their kefir fix. But like all good trends, there’s a bunch of conflicting information, confusing theories, and some straight up whack sh*t. I thought it was time we cleared some stuff up.

“We have 10x more bacteria that we have human cells”

A commonly cited figure is that we have 10x more bacteria in our bodies than we have human cells. And this is what a lot of scientists used to believe. Then that figure changed to a ratio of 3:1. But new evidence suggests that it’s probably more like 1:1.

The main point though is that the microbiome and gut health is a relatively new field of science and we just don’t have all the answers yet. Plus everyone is different, people probably have somewhere between 30-50 TRILLION bacteria in and on their body. But that’s still a difference of 20 TRILLION! That means everyone will react differently to fibre, probiotics, and prebiotics because of their own unique bacterial signature. One size doesn’t fit all; be super skeptical of anyone telling you to ‘eat this food for better gut health’. NOPE  🙅  doesn’t work like that.

“Candida overgrowth leads to ‘leaky gut’”

Oh boy, this is a big one. And it’s very confusing because just about everything gets blamed on a ‘leaky gut’, especially by alternative practitioners. But leaky gut is actually just a symptom of a much bigger problem. Our guts are lined by a single layer of cells called the epithelial layer. On top of that is a layer of mucous and, well, it’s basically goo. This prevents bacteria and other things coming in contact with the epithelial layer. Nutrients and some medicines can easily pass through the mucosal layer though, and then get absorbed or transported across the epithelial layer and into the blood stream to be taken to the liver.

The mucosal layer usually keeps any larger particles and anything too sketchy from coming in contact with the epithelial layer. Some pretty common substances, like alcohol and certain pain killers can cause the epithelial layer to become more porous – BUT, gastroenterologists don’t believe this causes any lasting problems or damage; as soon as you stop taking the medicine/ drinking the booze, any inflammation clears up and spaces between cells close back up.

Some people may have a “leaky gut” for other reasons, like Chron’s disease, coeliac disease or even chemotherapy treatment. But it’s important to remember that it’s a symptom of other issues and not something that needs to be treated.

That brings me to candida – it totally gets the blame for “leaky gut”. Candida is actually a family of yeasts (genus) – and there are TONS of different species of candida; some of which can cause infections like thrush, others which are pretty chill and make up part of your normal (or commensal) microbiome. There’s no solid evidence (maybe a couple of sketchy papers) to connect Candida overgrowth with increased gut permeability or any of the other shit it gets blamed for (other than thrush which is caused by a specific strain of Candida).

This is why it’s important to get your nutrition advice from credible sources; not from someone who read this one paper that said this thing… You can find ‘evidence’ for just about everything, but just because one study found a particular outcome doesn’t make it a universal truth. Scientists need to come to a consensus based on the preponderance of evidence, not just a few shady papers.

What I find totally bonkers about this whole candida and leaky gut thing, is the so-called ‘treatment’ for it. Basically eliminating all ‘sugar’. This is so confusing because basically all nutritious foods have some sort of sugar in them, including fruits and vegetables. Even fibre is made up of sugars, technically speaking. In my nutrition practice I’ve seen so many people cut out nutritious foods because they’ve been told to avoid ‘sugar’, without any real understanding of what sugar is. By cutting out foods that contain any sort of carbohydrate, you’re usually just cutting out a whole load of fibre, something we’re pretty sure actually improves gut health! If you’re still confused you can read more about sugar here and here.

I want to point out here too that the ONLY person who can diagnose you with anything is a doctor. RDs can help you if you have a particular health condition you’re suffering from, and RNutrs can help you make healthy changes to your diet. Anyone who claims they can treat or cure your condition (and isn’t a doc) is pretty suspect. Also, watch out for tests that claim to test for Candida (that aren’t from your doctor) a lot of them are really shady and not backed up by science. If you suspect you have thrush, go see your GP or a pharmacist and get some GD antifungals.

“Fermented foods are probiotics”

I see people call fermented foods probiotics ALL THE TIME, but it’s kind of misleading. There are loads of different kinds of fermented foods like yoghurts, cheeses, miso, pickles, sauerkraut and kefir that contain live microbes (if they haven’t been heat treated or pasteurised.) BUT to meet the definition of a probiotic they have to have a specific health effect and contain large enough numbers. Or if you want to get technical about it – probiotics are ‘live microorganisms which when administered in adequate amounts confer a health benefit on the host’.

While fermented foods do have some live bacteria, they haven’t been as rigorously tested as probiotics used in clinical applications. We don’t know exactly which bacteria are in your favourite kombucha, so we don’t know what their specific health effect will be. We don’t know how many are there; many beneficial microorganisms are anaerobic, meaning they can’t survive in oxygen rich environments, so as soon as you open your pot of yoghurt, the bugs are done for. There is a question of viability of these organisms, both in terms of the food they’re in, and whether or not they survive the acid in your stomach and actually reach the large intestine.

See Also

To be clear, I’m not saying that fermented foods don’t have any health benefit – just that we can’t call them probiotics. Basically, there isn’t enough science, yet.

“Adding more fibre & fermented/soaked/sprouted foods to your diet is the best way to improve gut health.”

People love to be able to buy stuff to help solve problems. I get it; it makes you feel like you’re actually doing something. But chances are that if you’re suffering from bloating and mild digestive issues (i.e. not IBS) then there are lots of things you can do without spending any money.

I hate to be the mum here, but you need to put your damn phone down; eating while distracted usually means we eat faster than we should be, which then means we’re not chewing our food enough – research suggests chewing about 20 times before swallowing! If you’re shovelling food into your face really fast, you’re going to swallow a bunch of air that will make your feel really full and bloaty.

Sometimes we’re just not eating regularly enough; make sure you have (reasonably) consistent meals and don’t let yourself get OVER hungry. Pay attention to how many fizzy and caffeinated drinks you’re having; sometimes these are the culprit of weird digestion issues. And, probably the biggest thing to look at is stress – people who don’t have good stress management can suffer IBS like symptoms.

Finally, for some people who have IBS, adding more fibre might actually make symptoms worse! That’s why it’s so important to make sure you get individualised advice from a qualified nutrition professional!

For more nutritional myth-busting, make sure you catch Laura Thomas will at the HBC Summit on 15th April.

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