Your gut microbiota (GM) is like your fingerprint: its composition is totally unique to you. That’s because it comprises over 100 trillion bacteria, viruses and fungi. Identical twins only share around 34% of their GM, demonstrating that genetics only play a small part in your gut microbial make up. Diet, lifestyle, stress, medication and other factors also contribute. In fact, the people you live with, and even your pets, can influence your GM. One study showed that a 10 second kiss results in an average transfer of 80 million bacteria!
The good news is most of the above factors are adjustable. We can change our microbiome, and our health, for the better (not that I’m suggesting we should change our partners of course). Best of all, research shows changes in our gut can take place within days of dietary modulation. In this article, I focus on prebiotics and probiotics, explaining how their synergistic relationship can influence our overall health.
Prebiotics are non-digestible carbohydrates (e.g. dietary fibres) that are not broken down or absorbed in the small intestine and arrive in the large intestine undigested. But that’s not all. In order to earn the “prebiotic” title, these fibres must be proven in clinical trials to confer a health benefit to their host.
Probiotics are live “good” bacteria that survive the digestive process, in order to reach and populate our gut microbiome. Again, for a microbe to be classified as a “probiotic”, it must prove real benefits in trials. Things get really interesting when we look at the favourite food of probiotics. Guess what? It’s prebiotics, as without them probiotics cannot thrive. Good bacteria love to feast on prebiotic fibres.
- Gut integrity: “Good” bacteria thrive on prebiotics and preferentially populate our gut at the expense of “bad” bacteria. Survival of the fittest you might say. Good bacteria produce Short Chain Fatty Acids (SCFA) as a result, which fuel the protective cells linings our gut, helping to keep the gut lining healthy and intact.
- Gut immunity: Around 70% of our body’s immune tissue is packed in our gut: an impressive, and essential, first line of defence against invading pathogens. Good bacteria help “train” our immune cells to recognise friend from foe, thereby optimising our intestinal immunity.
- Gut function: Good bacteria produce a wide range of bioactive molecules, believed to influence gut motility, appetite regulation, inflammation, and fat re-absorption, pointing to a critical role in inflammatory conditions and obesity.
- Systemic health benefits: Short Chain Fatty acids (SCFA), produced as a by-product of prebiotic fermentation by good bacteria, are thought to be responsible for a multitude of whole-body benefits. Among others, balancing our blood sugar, insulin, and blood lipid levels, hence reducing our risk of diabetes, heart disease, metabolic syndrome.
- Mental health benefits: Good bacteria produce key neurotransmitters (such as Serotonin and GABA), which regulate our mood, sleep, fear and anxiety. It’s estimated 90% of our serotonin, a.k.a. “happy” hormone, is produced in the gut. The constant two-way communication pathway between our gut and our brain, known as the gut-brain axis, is the focus of exciting new research into mental health, and the GM is right at the heart of this cutting-edge thinking.
Ours to Optimise
Unlike our fingerprint, we can change our microbiome, and simple dietary changes are a good place to start.
You can gradually increase your prebiotic intake with:
- Fruits, such as apples, apricots, dates, nectarines, grapefruits, watermelon, pomegranate, dried fruit
- Vegetables, such as artichokes, asparagus, beetroot, chicory root, fennel, garlic, leeks, okra, onions
- Grains and nuts, such as almonds, barley, cashews, hazelnuts, pistachios, rye, spelt
- Legumes, such as black beans, butterbeans, chickpeas, lentils, kidney beans, soybeans
Natural probiotics can be round in fermented foods, such as live yoghurts, crème fraiche, unpasteurised fermented cheeses, kefir, kimchi, miso, tempeh and pickles (e.g. gherkins). Probiotic supplements can be useful in some circumstances, but it’s important to choose the right strains for your specific needs, as different bacterial strains offer different health benefits.
If you’re looking to improve your overall health, start with your gut. Focus on optimising your GM with gradual improvements to your diet, exercise, sleep, and stress management, and don’t give up. Over time, your GM will return the favour 10 times over.
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- Shaping the oral microbiota through intimate kissing | Microbiome | Full Text (biomedcentral.com)
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- State of the Art Review: The role of the gut microbiome in systemic inflammatory disease (nih.gov)
- The intestinal neuro-immune axis: crosstalk between neurons, immune cells, and microbes | Mucosal Immunology (nature.com)
- Probiotics may help boost mood and cognitive function – Harvard Health
- How to get more probiotics – Harvard Health