Effect of food on gut microbiome
In fact, you have more bacteria that live in your gut than cells in your body. Microbiome refers to the group of up to microbes, or 1,000 bacterial species, that live in your body. This bacteria helps with digestion, destroys harmful bacteria and helps control your immune system.
The human microbiome consists of trillions of microorganisms — also called microbiota or microbes — spanning thousands of different species. These include not only bacteria but fungi, parasites and viruses. In a healthy person these "bugs" coexist peacefully, with the largest numbers found in the small and large intestines, though they are present throughout the body.
Microbiota do measurable work for the body. They stimulate the immune system, break down potentially toxic food compounds, and synthesise certain vitamins and amino acids, including the B vitamins and vitamin K. The key enzymes needed to form vitamin B12 are found only in bacteria, not in plants and animals. Microbiota also help break down sugars, starches and fibres using their own digestive enzymes.
Probiotics are foods that naturally contain microbiota, or that contain live active bacteria. Examples include lactic acid bacteria (LAB), yogurt, cheese and pickles. For a food and beverage manufacturer, these are product categories whose value proposition depends on keeping cultures live and viable through processing, packing and distribution.
Diet plays a large role in determining which kinds of microbiota live in the colon. A high-fibre diet in particular affects the type and amount of microbiota in the intestines. Fermentation releases short chain fatty acids (SCFA), which lower the pH of the colon; that lower pH in turn determines which microbiota can survive in the acidic environment, and limits the growth of some harmful bacteria such as Clostridium difficile.