Yep, the studies are underway. It’s a possible bridge in the knowledge gap between disease and diet. I’m pretty sure this will be the hot topic for nutritionists in the near future and even fuel for new fad diets.
Quoted from Part 1: The Human Gut Microbiome in Health and Disease by Matthew J. Bull, BSc, PhD and Nigel T. Plummer, PhD (Integr Med (Encinitas). 2014 Dec; 13(6): 17–22.):
“The bacterial cells harbored within the human gastrointestinal tract (GIT) outnumber the host’s cells by a factor of 10 and the genes encoded by the bacteria resident within the GIT outnumber their host’s genes by more than 100 times. These human digestive-tract associated microbes are referred to as the gut microbiome. The human gut microbiome and its role in both health and disease has been the subject of extensive research, establishing its involvement in human metabolism, nutrition, physiology, and immune function. Imbalance of the normal gut microbiota have been linked with gastrointestinal conditions such as inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS), and wider systemic manifestations of disease such as obesity, type 2 diabetes, and atopy.”
There is a necessary balance of microbes to maintain a rich microbiome. Not only the type of microbes but also the quantity of microbes found in the gut are important. The newest investigations are exploring how the bacterial balance in our digestive tract affect our well-being. Findings reveal that a healthy gut is important in stabilizing weight, controlling cholesterol, decreasing inflammation, strengthening the immune system, and a slew of other benefits. “The ‘Western diet’, rich in animal protein, fats and artificial additives, and lacking in fibre, beneficial microbes, plant phytochemicals, vitamins and minerals, is thought to drive these conditions by encouraging gut dysbiosis. Evidence from recent dietary intervention studies suggest adopting a plant-based, minimally processed high-fibre diet may rapidly reverse the effects of meat-based diets on the gut microbiome.” (Tess Pallister and Tim Spector. Food: a new form of personalised (gut microbiome) medicine for chronic diseases? – Journal of the Royal Society of Medicine; 2016, Vol. 109(9) 331–336). So, what should we be eating more of to support our gut microbiome? Probiotics, prebiotics, and phytonutrients. What should we reduce? Animal fat/protein and processed foods.
Probiotics are found in fermented foods like miso, kefir, kombucha, apple cider vinegar, yogurt, and sauerkraut or kimchi (not pickled, there is a difference). Most of these can be used as condiments in cooking or consumed alone. Preboitics are produced in the body from soluble and insoluble fiber. Both types of fiber are available in whole grains, legumes (beans), nuts, seeds, fruits, and vegetables. The prefix phyto is Greek for plant, thus, phytonutrients are nutrients found in plants. There are over a thousand known phytonutrients to-date and there are many yet to be revealed. The benefits are still being discovered but some common phytonutrient groups are polyphenols, carotenoids, flavonoids, and curcuminoids. Many of these nutrients/chemicals benefit the microbiome as well as the entire body. Prebiotics, probiotics, and phytonutrients are all derived from plants.
Animal products are the core of a Western diet. It is common knowledge that the typical ‘Western’ diet increases chances of obesity, diabetes, cardiovascular disease, and cancer. It is an animal based diet, low in fiber, and high in processed foods. While meat may be a great source of protein, B vitamins, and minerals it should not be the focus of the diet. Animal fat and protein require the release of more bile acids for digestion. The Western diet is low in fiber which is needed to bind with the bile acid. When the acid is not bound to fiber and removed it increases cholesterol levels. Animal products don’t have to be eliminated, just reduced to make room for more plant foods. Processed foods can wreak havoc on a body. Most processed foods contain food additives and preservatives to extend shelf life, improve stability, add color, and enhance flavors. Emulsifiers are used to blend water and fat but increase inflammation in the lining of the intestinal tract which affects nutrient absorption. Many other food additives have been found to be harmful in ways that may not affect the gut microbiome specifically but are certainly worth avoiding.
Not all of this is exactly cut-and-dried. Every ‘body’ is different – different genetic tendencies, different food preferences, different chemical balances, different lifestyles, etc. Scientific studies reveal that a healthy microbiome for one person may have different attributes than those of another and they may change over a lifetime. Still, the overall picture stays the same. Eating a plant-based diet will supply a human body the most important macro and micro nutrients needed to maintain wellness. We don’t have to become vegan or vegetarian to gain benefits and we don’t have to be lulled into the newest diet trend. Just learn to love the foods that love you back and your whole body (including your microbiome) will thank you for it.