Probiotics and the gut microbiome
Living in your gastrointestinal tract are more than a trillion micro-organisms, including bacteria, archaea, viruses and yeasts. Collectively they are known as your gut microbiota, gut flora or gut microflora.
Many of these micro-organisms are essential for your immune system, mental health and overall well-being. This is on top of their obvious positive impact on your digestive health, which is why they’re often described as ‘good’ or ‘friendly’ bacteria.
Some of the ways having the right balance of gut microbiota is thought to boost your health include:
Improved Digestion – studies indicate that several probiotic strains are highly effective in relieving digestion issues such as IBS.
Healthy weight – studies suggest having an imbalance of ‘good’ and ‘bad’ microbes may lead to weight gain.
Strong immunity – scientists understand that your gut microbiota forms a crucial part of your immune system.
Heart health – researchers have found significant links between gut microbiota health and levels of blood fats.
Diabetes risk – research shows gut microbiota may help control blood sugar and even reduce the risk of diabetes.
Allergies – experts think gut microbiota play an important role in the development of allergic diseases, especially in early years.
Skin – studies suggest a healthy gut microbiota may be one of the keys to having good skin and can even be effective when applied topically.
In a nutshell, probiotics are micro-organisms that are good for you, hence introducing more positive strains is good for your health. But if you really want to boost their levels, you need to ‘feed’ them with prebiotics.
How prebiotics support probiotics in the gut
Prebiotics are substances found in certain foods. They’re non-digestible fibres, complex sugars and other substances that we can’t digest ourselves. Instead, the probiotic bacteria in your gut ferment and break them down. By providing both structure and fuel to help the good guys thrive, prebiotics boost procreation of positive bacterial strains in your gut. And anything that’s good for the balance our gut microbiota, is good for our general health.
Prebiotics were first identified in 1995 by Glenn Gibson – a professor at the University of Reading. Gibson co-wrote a scientific paper introducing the concept with Professor Marcel Roberfroid of the Université Catholique de Louvain in Belgium.
What types of prebiotics should I eat?
Prebiotics are found in supplements and a range of foods. You’ve probably already eaten some today. There are several different groups of prebiotics, each of which has different types and food sources.
There are several types of prebiotics, including:
Fructooligosaccharides (FOS): Naturally occurring carbohydrates found in foods such as bananas, onions, garlic, and asparagus. FOS are not digested in the small intestine and serve as food for beneficial bacteria in the colon.
Inulin: A type of soluble fibre found in foods such as chicory root, Jerusalem artichokes, and dandelion greens. Inulin acts as a prebiotic by promoting the growth of beneficial bacteria in the gut.
Galactooligosaccharides (GOS): Similar to FOS, GOS are carbohydrates that are not digested in the small intestine and reach the colon intact. They can be found in foods like legumes, lentils, and certain grains.
Resistant Starch: Certain types of starch, such as that found in unripe bananas, cooked and cooled potatoes, and whole grains, resist digestion in the small intestine and serve as a substrate for fermentation by gut bacteria.
It’s ideal to try to eat all of them in your regular diet.
How to eat more prebiotics
Of course it’s more useful to know how to eat more prebiotics than to know all their names! Here are the best food sources for each type of prebiotic:
Fructooligosaccharides (FOS): Bananas, onions, garlic, leeks, asparagus, artichokes, and wheat.
Inulin: Chicory root, Jerusalem artichokes, dandelion greens, garlic, onions, leeks, bananas, and asparagus.
Galactooligosaccharides (GOS): Legumes (such as beans, lentils, and chickpeas), certain grains (such as barley and oats), and some vegetables (such as broccoli and cabbage).
Resistant Starch: Unripe bananas, cooked and cooled potatoes, legumes (such as lentils, chickpeas, and beans), whole grains (such as oats and barley), and certain seeds (such as flaxseeds and chia seeds).
Can I take prebiotic food supplements?
With such a variety of probiotic food supplements to choose from, you may well be wondering if any one of them stands-out as better at feeding your gut microbiota than another.
Mushrooms are becoming increasingly popular as health foods and supplements. It is thought many of their benefits come from high levels of undigestible polysaccharides: which are basically a compounds made up of various prebiotic fibres.
Unfortunately, not really. Whilst there are some good all-rounders such as inulin and many probiotic strains react positively to a variety of prebiotics. At the end of the day; different bacteria ferment different prebiotic compounds better than others. This is all to do with their genes and the size and structure of the prebiotic molecules.
Since there’s no single prebiotic for all your intestinal bacteria needs, as is often the case, the main takeaway in terms of nutritional advice is that it’s a good idea to get a wide variety of foods in your diet. Or if you can’t achieve this, make sure you choose well-formulated supplements to fill in the gaps.
Synbiotic Foods – prebiotics and probiotics combined
A food or supplement that is a mixture of prebiotics and probiotics is referred to as ‘synbiotic’ to describe the inherent relationship that beneficially affects the host by improving the survival & activity of beneficial microorganisms in the gut.
One neat way to get both nutrients is to introduce synbiotic food combinations into your diet (Food pairings that provide a dose of probiotics and prebiotics in every bite). Here are a few to get you started:
Live yoghurt and banana smoothie: Live yoghurt for probiotics, bananas for prebiotics (Choose slightly under-ripe bananas for even more prebiotic power!).
Hummus on sourdough toast: Sourdough bread for probiotics, hummus for prebiotics.
Cheese on flaxseed crackers: Cottage cheese for probiotics, flaxseeds for prebiotics.
Miso soup: Miso – fermented soya beans – for probiotics, spring onions and tofu for prebiotics.
Greek salad: Feta cheese for probiotics, raw onions and olives for prebiotics.
How much prebiotics and probiotics should I eat?
One of the best things about prebiotics and probiotics is that, unlike many other nutrients, you can’t really take too many or too much. After all, your gut is already teeming with trillions of different microbial life forms, so introducing a few billion more of the good ones isn’t likely to have any long-lasting adverse effects.
For this reason, even high-strength probiotic food supplements are perfectly safe for children and adolescents to take. Furthermore, there is plenty of research to suggest that a healthy gut biome is, if anything, even more important in early life and could have an influence on the development of all sorts of health conditions such as allergies, digestive issues, disease and even mental health.
However, when you start a new probiotic/prebiotic regimen – either by changing your diet or taking supplements (or both) – it’s worth bearing in mind that you may experience some short-term side effects as your gut adjusts to it’s new balance, such as bloating, wind and other digestive upsets.
This re-balancing effect is why high fibre foods have a reputation for causing gas, and may also explain why you get tummy troubles at the start of your holiday when you’re eating foods your digestive system isn’t used to.
If this is your experience, do not be concerned – this should stop after a few hours, or days at the most. In some ways it’s actually a good sign because it implies that a significant re-balancing is occurring.
However, if symptoms persist for longer than a few days then you may, understandably, want to stop eating the particular food or supplement causing the issue for a short time. You can then re-introduce it at a lower dose or quantity to build-up slowly and give your gut more time to adjust.
