In Ancient Greece, Hippocrates believed that all diseases start in the gut. Thousands of years later and it looks like he had a point. More and more evidence is emerging that points to the pivotal role of the gut in health and disease and at gut bacteria (the microbiome) in particular.

We each have trillions of bacteria living in our gut, taking up residence from the moment we are born (some research suggests they might even start colonising before birth) and changing throughout our life span, influenced by everything from diet to medication, stress and trauma and even lifestyle choices.1 So far, research has shown that these bacteria can have a great effect on maintaining the mucosal barrier in the gut (to stop bad guys getting out into the bloodstream and wreaking havoc)1, extracting nutrients and energy from food (it has even been suggested that obese individuals have bacteria that is especially adept at this)2, and in immunity – 70% of your immune system is actually in your gut!1 Evidence also shows a gut-brain connection, and there is a link between disturbance of gut bacteria and mood, with one study alleging 60% of anxiety and depression patients had bacterial imbalance.3 Much more research is needed but the implications for our health are really exciting.

An aspect of gut bacteria that I see most commonly in clinic is something called ‘dysbiosis.’ This is when beneficial bacteria and less beneficial bacteria become imbalanced.4  Symptoms are incredibly varied, ranging from IBS type symptoms, tummy aches, flatulence, abdominal discomfort, irregular bowel habits, to symptoms that you might not think could be connected to the gut – for example fatigue, aches and pains, anxiety, depression. Dysbiosis is something I often look to address first, before moving on to look at a client’s other imbalances, because if the gut isn’t working optimally it can be very difficult to adequately process and absorb all the nutrients needed to keep the rest of the body functioning optimally.

The great news is that we can use diet to keep our gut bacteria happy, and here are some ideas you can try:

  1. Gut bacteria love veggies, and they love variety! So try to eat a rainbow everyday – orange, red, purple, white, green veggies. Not only will you reap the benefits of a variety of antioxidants, polyphenols and phytonutrients but you’ll also be getting a healthy dose of fibre. Fibre helps your bacteria thrive.5
  2. Fermented foods: natural yoghurt, kefir, kombucha, sauerkraut, miso, kimchi, apple cider vinegar, fermented pickles, tempeh, unpasteurized cheese. These contain bacteria that can help to colonize your gut with the good guys. (Top tip – always buy fermented foods that have to live in your fridge. If it’s a store-cupboard item, it probably doesn’t have enough bacteria. For example, most supermarket pickles will not be fermented – you’d have better luck at a health food shop. You could also try making them yourself.)6
  3. Reducing processed foods and alcohol. These are bad news for the gut, suppressing good bacteria and feeding the bad guys.7
  4. Don’t take antibiotics unless your GP tells you they’re necessary. Antibiotics flush out all bacteria – good and bad. Interestingly, a recent study suggests that the microbiome recovers more quickly than previously thought from a course of antibiotics, but several key beneficial strains of bacteria take slightly longer.8 If you have had to take antibiotics, try to gradually reintroduce bacteria.
  5. Lifestyle – stress, lack of sleep and lack of exercise have all been linked to a reduction in the diversity of gut bacteria. Try to relax, get enough shut-eye and exercise regularly.9

It’s important to take it slow when introducing more fibre or fermented foods into your diet. Adding too much too soon can result in more digestive symptoms – particularly abdominal discomfort and wind. It is also possible to take probiotic supplements, which can be really helpful for certain individuals. I would always suggest trying a ‘food-first’ approach – get as much as you can from your diet before turning to supplements.

References

  1. Thursby, E. and Juge, N. (2017). Introduction to the human gut microbiota. Biochemical Journal, 474(11), pp.1823-1836.
  2. Castaner, O., Goday, A., Park, Y., Lee, S., Magkos, F., Shiow, S. and Schröder, H. (2018). The Gut Microbiome Profile in Obesity: A Systematic Review. International Journal of Endocrinology, 2018, pp.1-9.
  3. Liu, L. and Zhu, G. (2018). Gut–Brain Axis and Mood Disorder. Frontiers in Psychiatry, 9.
  4. Hooks, K. and O’Malley, M. (2017). Dysbiosis and Its Discontents. mBio, 8(5).
  5. Hiel, S., Bindels, L., Pachikian, B., Kalala, G., Broers, V., Zamariola, G., Chang, B., Kambashi, B., Rodriguez, J., Cani, P., Neyrinck, A., Thissen, J., Luminet, O., Bindelle, J. and Delzenne, N. (2019). Effects of a diet based on inulin-rich vegetables on gut health and nutritional behavior in healthy humans. The American Journal of Clinical Nutrition, 109(6), pp.1683-1695.
  6. Rezac, S., Kok, C., Heermann, M. and Hutkins, R. (2018). Fermented Foods as a Dietary Source of Live Organisms. Frontiers in Microbiology, 9.
  7. Zinöcker, M. and Lindseth, I. (2018). The Western Diet–Microbiome-Host Interaction and Its Role in Metabolic Disease. Nutrients, 10(3), p.365.
  8. Palleja, A., Mikkelsen, K., Forslund, S., Kashani, A., Allin, K., Nielsen, T., Hansen, T., Liang, S., Feng, Q., Zhang, C., Pyl, P., Coelho, L., Yang, H., Wang, J., Typas, A., Nielsen, M., Nielsen, H., Bork, P., Wang, J., Vilsbøll, T., Hansen, T., Knop, F., Arumugam, M. and Pedersen, O. (2018). Recovery of gut microbiota of healthy adults following antibiotic exposure. Nature Microbiology, 3(11), pp.1255-1265.
  9. Conlon, M. and Bird, A. (2014). The Impact of Diet and Lifestyle on Gut Microbiota and Human Health. Nutrients, 7(1), pp.17-44.