Can your gut flora, aided by probiotics, help you lose weight?
Fermented food is suddenly trendy again; just walk through the aisles of any health shop and you’ll see items like kombucha and miso on the shelves. Top local restaurants have dishes like kimchi (pickled vegetables) on their menus, and with the help of sites such as Fermenting for Foodies (www. fermentingforfoodies.com) you can learn how to make your own.
These are all clear signs that the human gut microbiome – the ecosystem of microorganisms such as bacteria in your intestinal tract – is now garnering mainstream interest. The gut microbiome holds the secret to weight loss, health, energy and joie de vivre, writes Raphael Kellman in his book The Microbiome Diet: The Scientifically Proven Way to Restore Your Gut Health and Achieve Permanent Weight Loss.
British lifestyle site Byrdie (www.byrdie.co.uk) even rates the so-called ‘gut diet’ as one of the best ways to lose weight.
Seems easy enough, right? So all you have to do is eat a variety of veggies, fruits, wholegrains, seeds, nuts and fermented foods – the kinds of food that make your good bacteria flourish? That’s a good start, sure.
Unfortunately, the secret to losing weight isn’t that simple.
The Germans love their sauerkraut, the Russians eat borscht and the Koreans have kimchi with nearly every meal.
CAN GUT BACTERIA MAKE YOU FAT?
Sadly, our bodies aren’t as selfsustaining as we once thought. They are like a complex ecosystem with trillions of bacteria and other microorganisms, living mostly in our intestines. Over the past few decades, research on the far-reaching influence of the microbiome has become a hot topic.
More and more research shows that this micro-population can also affect your metabolism – and thus your weight. This has led scientists to ask: is the current obesity crisis linked to the microbiome? There is a growing body of proof that indicates that our gut flora is being negatively affected by the trappings of modern life, specifically the overuse of antibiotics and our sugar intake.
Researchers are looking into the specific ways that a skinny person’s intestinal tract differs from that of an overweight person’s, and there are definite indications that some types of gut flora play a crucial role, influencing both metabolism and appetite.
We know that our bodies need a healthy balance of good bacteria and bad bacteria to be in perfect health. Now, we’ve also learnt that the ‘good’ bacteria have to be balanced.
This is how Paarl-based dietician Mariza van Zyl, author of Dik vir Dieet, sums it up: an excess of ‘bad’ bacteria causes diseases. But the balance between the different ‘good’ types can also be disturbed, because each of them has a different job. Variety is the keyword here. An ecosystem such as a game reserve has to have different types of wildlife: too many lions and they’ll eat all the other animals. The same goes for the ecosystem in your intestinal tract, or your gut flora.
So here’s the problem: research shows that people in the Western world, where obesity is rife, have a less diverse ecosystem than people living in developing countries.
WE WANT MORE!
What we want much more of is a family of bacteria with a difficult-to-pronounce name: Christensenellaceae. An abundance of it has been linked to slimness – and vice versa. But it is not the only bacterium that can affect the size of your jeans.
You need to strive towards having a wide variety, says Dr Jeffrey Gordon of the Washington University School of Medicine, who was one of the first experts to discover a link between obesity and gut bacteria. A slim person’s gut flora is about 70% more diverse than an overweight person’s.
‘Every study we do shows that there is a difference between the microbiome of slim and overweight people, says Dr Tim Spector, author of The Diet Myth: Why the Secret to Health and Weight Loss is Already in Your Gut. He was the lead researcher of a team that investigated the gut flora of identical twins who differed in weight. By just looking at the gut microbes, they could accurately predict which twin was overweight.
Besides their gut microbiomes being more diverse, the skinnier twins also had a greater abundance of Christensenellaceae.
Your gut population can also play a role in hunger. One bacterium, named Helicobacter pylori, appears to be key. It is the bacterium found in cases of stomach ulcers and stomach cancer – antibiotics have helped to halve H. pylori infections, which is good news if you have a stomach ulcer, but not so great for your waistline. H. pylori actually has a protective effect on your whole body, as long as it doesn’t grow wildly and get out of control, says Mariza.
The bacterium seems to lessen the body’s production of ghrelin, aka the hunger hormone. If you wake up hungry in the morning, it’s because ghrelin is telling you that you need to eat, according to Dr Martin Blaser, author of Missing Microbes: How the Overuse of Antibiotics is Fueling Our Modern Plagues. When you eat breakfast, your ghrelin levels are lowered. But if have no H. pylori in your system, this doesn’t happen – so you eat more.
WHAT YOU CAN DO
Where does this information leave you? Some of your gut microbes may be determined by your genes, but lifestyle and diet also play significant roles. For instance, if your diet consists mainly of meat and dairy, Bilophila wadsworthia
(a bacterium linked to colitis, or inflammation of the colon) will flourish. If you eat mainly plantbased foods, it will diminish.
Mariza says the number of bacteria in your digestive system and how well they’re balanced are determined by many factors. Passing through the birth canal has a good effect on your digestive system, so it’s a plus if you were delivered naturally, and if you were breast-fed. If, on the other hand, you regularly take antibiotics or continually disinfect your hands, it can have a negative effect on your gut flora. Their numbers, strains and whether they help you out or trip you up are also influenced by the lack or presence of certain nutrients, such as vitamin A, as well as things you do or don’t do.
‘We go out of our way to save the rhinos and the whales,’ says Dr Francois Retief, a gastroenterologist from Mossel Bay. ‘But we are completely oblivious to the ecosystem inside our bodies and how our lifestyle affects it. You need to listen to your body: eat when you are hungry, sleep when you are tired and drink water when you are thirsty.’
REBUILD YOUR MICROBIOME
If probiotics (like fermented foods) are the ‘seeds’, prebiotics (like fibre) are the ‘fertilisers’ in your microbiotic ‘garden’.
Fermented foods are good sources of probiotics, and eating them is the best way to replenish the good bacteria in your gut. Which is why it is an integral part of nearly every culture’s traditional cuisine. In Japan and China, fermented soya products such as miso, soya sauce and tempeh are part of the daily diet. The Germans love their sauerkraut, the Russians eat borscht and the Koreans have kimchi with nearly every meal. Locally, we have amasi, a form of fermented milk, and suurpap, which is made with millet, maize meal or sorghum.
Probiotic yoghurt is a good source of good bacteria; however, if you tend to stick to the same brand, you might only be ingesting one strain. Your gut, however, is host to many different strains.
The same goes for probiotic supplements. You might be getting a variety of strains in one pill, but it is still not nearly enough. For the best results, vary brands to get the biggest possible variety and combine this with fermented foods.
‘We are completely oblivious to the ecosystem inside our bodies and how our lifestyle affects it. You need to listen to your body.’
• Eat more fibre of all kinds: the soluble kind (oats, beans) and the less soluble kind (wholegrains, wild and brown rice, vegetable peels like sweet potato skin) and insoluble fibre (onions, bananas, root vegetables). Other good sources are leeks, asparagus, garlic and artichokes. Research has shown that these foods feed your microbes and ensure a greater variety.
• Tannins in red wine and tea inhibit the growth of a bad bacterium called Clostridium.
• The polyphenol quercetin, found in onions, has been shown to inhibit the growth of E. coli.
• Avoid junk food. Your sweet tooth can wreak havoc on your gut flora; it needs complex carbohydrates such as vegetables, fruits, legumes and wholegrains to flourish. If you eat too many sweets and processed foods, your microbes remain hungry. Also stay away from preservatives.
• Eat the right fat, says Mariza: - choose cold-pressed plant oils - eat a variety of fats – more avocado, nuts and seeds, and less coconut and butter
- eat grass-fed or Karoo lamb - eat more oily fish, high in omega-3s, such as sardines and anchovies
- eat a handful of raw nuts
- avoid foods high in trans-fatty
acids, such as margarine
• Vary your menu: The more varied your diet, the more diverse your microbial ecosystem will be. Studies have shown that slim people have a densely populated and diverse gut-flora community.
• Get moving: The microbes in your gut that help to stabilise blood sugar levels multiply when you exercise. Research has shown that people who exercise regularly have higher levels of Akkermansiaceae, a bacterium that has been linked to lower obesity figures.
• The take-home message here? Eat more fruit, veg and fibre. Avoid processed food. Sleep. Exercise. And don’t take antibiotics the moment you feel the sniffles coming on! There’s a lot we don’t know, but it’s safe to say a healthy gut is associated with a healthy diet. And weight loss may just be the cherry on top. The Microbiome Diet: The Scientifically Proven Way to Restore Your Gut Health and Achieve Permanent Weight Loss by Raphael Kellman (Da Capo Press, 2015) is out now.