Is Our Weight Determined By Our Gut Bacteria?
New studies are revealing some VERY interesting findings about how different people react to different foods, and why some people seem able to lose/gain weight more easily than others.
Specifically, the research looks at how our bodies react differently to different sources of carbs.
It seems the high GI/low GI carb argument may be faltering, as recent studies are finding that different people may have polar opposite glucose reactions to the same foods. It’s no surprise that there is some variation between different individuals, but the magnitude of the difference is beyond all previous expectations.
Instead, our glucose responses (whether we have a sudden sugar spike or not) appear to be determined by our gut bacteria.
What does this mean?
Well each of us has a complex collection of bacteria living in our guts — our distinct microbiome. This comprises the trillions of microbes (100 trillion, in fact) in your intestines that help digest food, synthesize vitamins, regulate metabolism and make up your immune system. The studies show that the kinds of microbes you have in your gut (or don’t have) are a pretty good predictor of what foods you respond ‘well’ to and what foods you respond ‘poorly’ to, and hence how it affects your weight.
A vast study is being carried out by a team at the Weizmann Institute of Science in Israel. They are in the process of monitoring 1,000 people in minute detail to see exactly how their bodies react to food – and their first results are rewriting the textbooks.
Foods have been traditionally classified by how much of a blood sugar spike they cause – with “high GI” foods considered bad for us, and “low GI” considered good. Every nutritionist would tell you this. But the Israeli research, led by Dr Eran Segal and Dr Eran Elinav, suggests that it is simply not so. They have been comparing the gut microbes of the many study volunteers with their blood sugar responses.
Participants were connected to a glucometer, attached through the skin, recording blood sugar levels 24 hours a day for an entire week.
If you watch “Trust Me I’m A Doctor” on BBC (highly recommended viewing for anyone with an interest in health and nutrition), you’d have seen the vast difference in glucose responses in the two female participants of the same age. For example, for one of these women, pasta was “bad” – resulting in a significant sugar spike, but for the other it was fine. Their responses to bread were also complete opposites.
The most shocking revelation for the show’s participant (who happens to be an A and E doctor) was that “healthy” food such as grapes, orange juice and new potatoes all spiked her sugar levels. This is worrying because it means that, while you think you’re making the “right choice”, based on traditional health advice, you could actually be making things worse.
How could this be?
Well both women had very a different array of gut bacteria, and the researchers are starting to link different strains of bacteria with different food responses. Previous studies on mice and rats have also found similar results.
In general, the overall findings are that healthier people have a wider diversity of bacteria.
What is particularly interesting about these findings, however, is that – unlike our genes – we can actually alter and influence our microbes! So how do we do this?
Foods for Improving Gut Flora
- Yogurt – This is probably the best known probiotic source. Probiotics are “friendly bacteria” that are naturally present in the digestive system. Did you know there are tens of billions of bacteria per serving of yogurt? Though some brands have more live cultures than others. Try and avoid the sweetened types and go for natural greek yoghurt (Fage Total Greek is my all-time fave).
- Kimchi – Spicy and sour, this traditional Korean side dish is made by fermenting cabbage, cucumber or radish with spice. It’s mainly pickled vegetables and full of healthy micro-organisms. It’s usually found in Asian restaurants or Asian supermarkets. Sauerkraut (fermented cabbage) has a similar effect.
- Bananas – They work to maintain harmony among microbes in the bacterial community, known as phyla. This is one reason bananas are a standard prescription for an upset stomach. Bananas may also reduce inflammation, due to high levels of potassium and magnesium.
- Miso – Soybeans fermented with brown rice produce miso paste, a popular seasoning used in Asian cuisine. The fermentation process is what makes this condiment a source of lactobacillus acidophilus. Since it has a strong, salty flavor, a little goes a long way!
- Onions & Garlic – These are rich in inulin. They also have some extra digestive benefits to them – they are great sources of sulfur, which acts like a weapon against harmful bacteria in the gut.
- Apple Cider Vinegar – Raw organic apple cider vinegar is made from organic apples and undergoes a double fermentation process. This produces enzymes and preserves many of its health-promoting characteristics. It’s therefore loaded with raw enzymes and gut-friendly bacteria.
- Dark Chocolate – YES chocolate! While we already know that cocoa is rich in antioxidants, according to researchers, beneficial microbes including Bifidobacterium and lactic acid bacteria also enjoy their chocolate. These friendly bacteria gobble up cocoa and turn it into compounds known to help the heart and reduce inflammation. As if you needed a reason to eat more! (Just ensure it’s at least 70% cocoa and try to keep an eye on sugars)
Fill Up On Fibre
In general, it’s always important to eat plenty of fibre for our digestive health – but you may not know that our bacteria feed off the fibre in our guts too. Some studies show that when microbes are starved of fiber, they can start to feed on the protective mucus lining of the gut, possibly triggering inflammation and digestive issues.
Cut Down Refined Sugars
Sugar promotes the growth of bad bacteria in the gut and thereby hampers the growth of beneficial species. Diets high in sugar, refined carbohydrates and processed foods can basically provide an all-you-can-eat buffet for the bad bacteria to thrive.
There’s evidence that a special relationship exists between our brain and our gut. Not only can stress alter the balance of bacteria, but it also reduces the gut’s microbial diversity (how many different types of bacteria we have). This is a two-way relationship, as better gut health has also been linked to better mental health and cognitive function. Some studies even link gut health to mental illnesses like depression.
Put Down The Antibiotics
You should already know by now that antibiotics will not do anything for a common cold. Although some illnesses do require the use of antibiotics, the truth is that we over-use them unnecessarily. The problem with this is – although they work to kill the bacteria causing whatever your illness is – they don’t discriminate between good and bad bacteria, so both will be depleted. This reduces overall gut biodiversity too. So only take them if absolutely necessary.
The Weizmann Institute’s dream is that anyone, from anywhere in the world, will soon be able to send in a small stool sample, have their microbes analysed, and be sent a personalised diet plan.This is a super interesting new area of research that could potentially change diet advice entirely. Although the idea of mailing poop to Israel doesn’t sound too glamorous, my hope is that this can be used to make diet and nutrition advice far more personal and tailored to the individual (and their gut).
Instead of counting calories or banning carbs we could soon be working with our own gut bacteria to help shift the pounds, and at the same time, protect ourselves from diabetes.
Hippocrates made this statement over 2,000 years ago and it seems truer today than ever:
“All disease begins in the gut.” – Hippocrates, the father of modern medicine.