Beans, lentils, and split peas are rich in fiber, resistant starch, and plant protein, and they are a low-glycemic carbohydrate source. The health benefits of these legumes sometimes get overlooked, but adding beans to your diet promotes weight loss, cardiovascular health, and insulin sensitivity.
The Microbiome in Action
The human microbiome is a complex collection of bacteria, viruses, fungi, and other microorganisms that inhabit body surfaces, including the skin and digestive tract. The majority of the microbiome lives in the gut, where there are more than 1000 different species of bacteria.The trillions of organisms in the gut microbiome are busy: They produce vitamins, such as K2 and B12, help develop immunity, enhance the benefits of some phytochemicals, and protect against pathogens. The bacteria of the microbiome convert dietary fiber and resistant starch from plant foods into short-chain fatty acids (SCFA) that protect intestinal cells and regulate metabolism. The gut microbiome can even be considered an organ of the human body; without it, the body would not function properly.
The intestinal mucosal immune system is a large and important part of the whole human immune system, and the microbiome is closely connected with intestinal immunity. The microbiome modulates the activity of immune cells, counteracts inflammation, and maintains the integrity of the intestinal barrier. This means we count on a healthy gut for a powerful immune response.
What Makes Beans Special?
Beans, lentils, split peas, and other legumes are rich in fiber and resistant starch, carbohydrates that can’t be broken down by human digestive enzymes.The bacteria that reside in the large intestine depend on “microbiota-accessible carbohydrates,” also known as prebiotics, to survive; prebiotics are food for gut bacteria. Without enough prebiotics in our diet, gut bacteria begin to consume an alternative energy source: the first line of our immune defense on the surface of the intestinal lining. This intestinal lining is made up of molecules called mucins.
All plant foods contain some prebiotics, but beans are special because they are very high in resistant starch, making them especially rich in prebiotics. Not all indigestible plant carbohydrates act as prebiotics, but resistant starch from beans provides large amounts of prebiotics. Prebiotics nourish the microbiome and allow for the production of SCFAs.
So the fiber and resistant starches from beans are waiting in our digestive tract and full of microbiota-accessible carbohydrates. To sum it up, we eat beans because they nourish our microbiome and promote the production of short-chain fatty acids. SCFAs help kick our immune system into gear.
Short-Chain Fatty Acids
Diet plays a large role in determining what kinds of microbiota live in the colon. Prebiotic fiber and resistant starch can only be broken down and fermented by enzymes from microbiota living in the colon. SCFAs are released as a result of this fermentation.Growing research on SCFAs explores their wide-ranging effects on health, including stimulating immune cell activity and maintaining normal blood levels of glucose and cholesterol.
The production of SCFAs is an essential part of the microbiome’s effects on immune function. SCFAs both have anti-inflammatory effects and promote integrity of the intestinal epithelial barrier. This barrier helps to prevent pathogenic bacteria in the gastrointestinal tract from causing an infection.
When we eat fiber- and resistant starch-rich foods, we support the growth and development of a healthy microbiome.
