Gut health is a hot topic. There's a lot of research being undertaken on the relationship between gut bacteria and our diets, and growing evidence of a link between mental health and the number and variety of bacteria species that inhabit our gut. So how do we help support our friendly gut bacteria?
Our gut bacteria thrive on the stuff we can't digest - dietary fibre. Dietary fibre is a form of carbohydrate, and is often referred to as "roughage". When we eat foods containing fibre, our digestive system works to extract the nutrients it can, and the remaining material (mostly fibre) travels through to the large intestine (colon) where it is fermented by our gut bacteria. While we don't derive any nutritional benefit from this process directly, the fermentation produces three types of short-chain fatty acids which offer numerous health benefits. One of these fatty acids, butyrate, is known for its anti-inflammatory and anti-cancer properties.
What we eat has a huge effect on the health and variety of bacteria living in our gut. A diet high in fibre - one that includes a variety of fruits, vegetables, wholegrains and legumes - will provide a steady supply of food for the little critters to thrive. By contrast, a diet rich in sugars, refined starches and animal proteins results in a smaller and less diverse bacterial population. In such circumstances, opportunistic pathogens (the kind of bacteria that can make us sick) have less competition, and are more likely to cause us trouble.
It doesn't take much for our gut bacteria to get out of whack. Along with a poor diet, smoking, stress, surgery, and the use of antibiotics can also effect gut bacteria. This altered state (known as dysbiosis) can impact on our health in many ways. It can reduce our immunity, affect our metabolism, decrease the production of certain vitamins, and contribute to inflammation in our body.
When the state of our gut can have an impact on so many aspects of our health, it's no wonder there is increasing interest in eating or avoiding specific foods, "superfoods" and various pills and potions to "heal our gut", as well as some unusual terms bandied about. A "leaky gut" is often proposed as a cause of a multitude of symptoms and complaints, and even some auto-immune diseases. However, "leaky gut" is not a legitimate medical term. What this term is attempting to describe is a degradation of the barrier function of the intestine, and an increase in intestinal permeability. This is mostly seen in individuals suffering from an Inflammatory Bowel Disease or Coeliac Disease, but dysbiosis may also play a part in its development. Interestingly, another benefit of the short-chain fatty acid butyrate (formed when gut bacteria ferments dietary fibre in our colon) is to enhance gut barrier function.
So, what steps can you take to improve your gut health?
Start by eating your 5+ a day. The fibre in fruit and veg is a great source of food for your friendly gut bugs. Wholegrains are also hugely important for gut health, and if you can choose wholegrain options for your breads and cereals as often as possible, it can make a big difference. I have seen clients who have virtually eliminated some very uncomfortable digestive issues (bloating, wind, constipation) through upping their veg and fruit intake, and making some easy swaps to wholegrain foods, to ensure they meet their dietary fibre requirements.
Which wholegrains are the best to eat for gut health?
If you have Coeliac disease, you will need to avoid anything containing gluten (traditional cereal grains such as wheat, oats, barley, rye) and instead consume pseudo-grains, such as quinoa, buckwheat, amaranth, chia seeds, corn, millet and rice. Otherwise, any of the wholegrains will provide just the kind of food your gut bugs will love. There is no need to limit yourself to the pseudo-grains to "heal your gut" - it's unlikely they will confer any additional benefits, and they can be comparatively expensive. Both traditional cereal grains and pseudo-grains provide high levels of phenolic compounds (compounds that benefit both gut bacteria and overall health), although buckwheat consistently has the highest phenolic content of all. In wheat, the majority of the phenolic compounds are found bound to the bran or outer layer of the grain, making consumption of the whole grain the healthier choice. The upshot is, if you don't have Coeliac Disease but like eating the trendy, gluten-free pseudo-grains then go for it, but traditional wholegrain choices are going to be just as good for your gut health.
If you are having gut issues, it always pays to see your General Practitioner to make sure there isn't an underlying medical cause. Once you have had that checked out, have a look at your diet - you might find an extra serve or two of fruit and veg, and some simple swaps to wholegrain options, makes a big difference to your gut health. Look after those little critters in your gut, and they will look after you.
References:
Gong, L., Cao, W., Chi, H., Wang, J., Zhang, H., Liu, J., & Sun, B. (2018). Whole cereal grains and potential health effects: Involvement of the gut microbiota. Food Research International, 103, 84-102. Retrieved from https://www.sciencedirect.com/science/article/pii/S0963996917307081
Inglett, G.E., Chen, D., & Liu, S.X. (2015). Antioxidant activities of selective gluten free ancient grains. Food and Nutrition Sciences, 6, 612-621. Retrieved from https://file.scirp.org/pdf/FNS_2015050513270711.pdf
Leech, J. (2018). What is leaky gut syndrome and is it even real? [Website]. Retrieved October 10, 2018, from https://www.dietvsdisease.org/leaky-gut-syndrome/
Levakova, L., & Lacko-Bartosova, M. (2017). Phenolic acids and antioxidant activity of wheat species: A review. Agriculture, 63(3), 92-101. Retrieved from https://content.sciendo.com/view/journals/agri/63/3/article-p92.xml
Mikulajova, A., Takacsova, M., Rapta, P., Brindzova, L., Zalibera, M., & Nemeth, K. (2007). Total phenolic contents and antioxidant capacities of cereal and pseudo cereal genotypes. Journal of Food and Nutrition Research, 46(4), 150-157. Retrieved from https://www.researchgate.net/profile/Anna_Mikulajova/publication/290264102
Thursby, E., & Juge, N. (2017). Introduction to the human gut microbiota: Review article. Biochemical Journal, 474, 1823-1836. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5433529/pdf/BCJ-2016-0510C.pdf