How Your Microbiome Feeds You

You’ve read a lot about the importance of your gut microbiome, and how you can feed it well to support your health. But did you know that those billions of bacteria also feed you with some very important nutrients? It’s a true symbiosis.

Vitamin production

Vitamins are nutrients that are vital for humans because we need them but can’t make them. Fortunately our friendly gut bugs can make some for us, because they have genes (that we don’t have), that make enzymes for the necessary biochemical reactions. We literally carry a vitamin-producing factory with us, everywhere we go. 

Unlike dietary vitamins, which are adsorbed in the upper part of the small intestine, most of the uptake of microbially produced vitamins occurs in the colon.

Some species of our gut microbiota synthesize most of the water-soluble B vitamins*, including biotin, folate, nicotinic acid (B3), pantothenic acid (B5), pyridoxine (B6), riboflavin (B2), thiamine (B1), and cobalamin (B12). In fact animals, plants and fungi cannot make B12: it is the only vitamin that is exclusively produced by microorganisms. So the vitamin B12 in the animal products we consume has all been produced by the animals’ microbiota. This is why you only find it in animal products, and supplements.

Those B vitamins are essential to some of the gut bacteria as well as to us. Our health and well-being are intricately entwined with the health and well-being of our microbiota in complex ways that research is just beginning to shine some light on.

The B-vitamins the bacteria make in the large intestine may perform many important functions in the body. In addition to nourishing us and our microbiota they may:

• regulate immune cell activity 

• suppress colonization by pathogenic bacteria

• modulate colitis (inflammation of the colon)

Up next: Vitamin K, which plays important roles in cardio-vascular health and bone density. While we consume vitamin K in different forms in our diets, some of our microbiota boost that by producing additional vitamin K2. There will be a SHINE Health post offering more information on vitamin K soon.

Short chain fatty acids may ring a bell for you as they came to prominence recently as the types of fats in coconut oil. The bacteria in our colon feed on carbohydrates and proteins that haven’t been digested as they passed through our small intestine, as well as proteins made by or sloughed off by the gut. This produces short chain fatty acids, the three main ones being:

• Butyric acid - important as an energy source for the cells that line the colon. It also may have some anti-cancer activity, as well as the ability to regulate gene expression and glucose production in the gut.

• Acetic acid - essential for growth of other bacteria, cholesterol metabolism and production of fats, and it affects appetite regulation.

• Propionate - also provides energy to cells that line the colon. It helps us feel satiated, and moves to the liver where it helps with glucose production.

The amino acids and peptides the colon bacteria produce for us help us in many ways, including benefits to mood and blood sugar regulation. The gut microbiota produce hundreds of other bioactive compounds, some of which help the overall microbial balance by supporting symbiotic species and suppressing competitive species. They also help us breakdown polysaccharides and polyphenols**, and we are still just at the beginning of our scientific understanding of their intricate, interactive and important capabilities.

* Brilliant B vitamins

** Polyphenol rich food chart