These bacteria are actually crucial for optimal health in humans. They play various roles related to weight management, blood sugar control, immunity, brain function and mental health (
They are so important that they are often referred to as the “forgotten organ” (
Because humans can’t digest fiber, it ends up reaching the large intestine mostly unchanged.
This is where fermentable fiber comes into play. These are fibers that the friendly gut bacteria are able to digest (ferment) and use as fuel (
This increases the number and balance of friendly gut bacteria, which also produce short-chain fatty acids with powerful health benefits (
Most fermentable fibers are soluble, but there are also some insoluble fibers that can function in this way.
Fermentable fibers include pectins, beta-glucans, guar gum, inulin and oligofructose.
The best whole-food sources of fermentable fibers are beans and legumes. A 1-cup serving often provides up to half of the recommended daily intake of fiber.
All that being said, one of the by-products of fiber fermentation is gas. This is why foods high in fermentable fiber can cause flatulence and stomach discomfort, especially if people are not used to eating a lot of fiber.
Fermentable fiber is digested and used as fuel by the friendly bacteria in the gut. This can lead to various beneficial effects on health.