In part 4 of my food for the gut posts, I’ve written about prebiotic foods. Most people have heard of probiotic foods but less commonly known are prebiotic foods – the foods that feed those good gut bacteria to help build & maintain a healthy microbiome.
You may have seen the latest commercial for Kellogg’s breakfast cereal. I have to say this add really ticked me off as they’ve taken a truth – our good gut bacteria feed on fiber – and manipulated it in a really inaccurate manner. Yes our good gut bacteria feed on (some) fiber – but not refined, sugary fiber. In fact research shows that sugar and refined carbohydrates feed the unwanted bacteria in our gut.
So that out of the way – sugary breakfast cereals aren’t going to improve your gut health – what sort of fiber does our gut love?
Not all fiber is prebiotic. The most recent definition of a prebiotic is, “A selectively fermented ingredient that results in specific changes in the composition and/or activity of the gastrointestinal microbiota, thus conferring benefit(s) upon host health” (Davari, D, et al. 2019). That’s a bit wordy but basically prebiotic fibers pass undigested through the gastrointestinal tract until they reach the colon (large intestine) where they are fermented by the gut bacteria. This process produces essential nutrients including short chain fatty acids which nourish your digestive system and as per the definition, confers health benefits. Improving gut health, improves overall health.
Other than their benefit to the microbiome (and probably due at least in part to their positive effect on the microbiome), prebiotics can improve mineral absorption, blood glucose & insulin profiles, support the immune system, healthy hormones & bones; possibly protect against colon cancer and intestinal infections & modulate inflammation.
Some of the best prebiotic foods include asparagus, Jerusalem artichoke, dandelion greens, leeks, onion, garlic, apples, bananas (the less ripe the better), cabbage, chicory root, konjac root, whole grains such as oats, wheat & barley & seaweed. This list is far from exhaustive, with more extensive lists found online (some of course more reliable than others).
I’ve found this one to be quite good: https://www.fwdfuel.com/wp-content/uploads/2019/05/Best-Prebiotic-Food-List-PDF.pdf. Note that generally the less foods are cooked, the greater the prebiotic value.
The beauty of course is that fermenting these fibers (such as cabbage in sauerkraut or kimchi), makes them both probiotic & prebiotic in nature.
So for a healthy gut microbiome it is important to not only include probiotic foods in your diet but also prebiotic foods.
References:
Davani-Davari, D., Negahdaripour, M., Kari
mzadeh, I., Seifan, M., Mohkam, M., Masoumi, S. J., Berenjian, A., & Ghasemi, Y. (2019). Prebiotics: Definition, Types, Sources, Mechanisms, and Clinical Applications. Foods (Basel, Switzerland), 8(3), 92. https://doi.org/10.3390/foods8030092