Fiber: the golden thread of digestion

The rapid advancements in science have brought about new findings on the topic of food and the importance of a diverse diet. One of the nutrients that came into the spotlight is dietary fiber. What is dietary fiber and why is it important?

What is fiber?

The widely accepted definition of dietary fiber states that fibers are oligomeric or polymeric carbohydrates that can not be digested in the small intestine. Instead, they pass through to the large intestine where they are partially or fully digested.

While passing through the digestive system, fiber binds water which allows it to control the consistency of the contents found in the gastrointestinal tract. Additionally, fiber fermentation promotes a healthy gut microbiome and increases gut motility. In this way, fiber helps in keeping digestion healthy and consistent.

Where can fiber be found?

Fiber can broadly be described as either soluble or insoluble. Soluble fiber dissolves in water and forms a viscous gel. It also ferments in the small intestine. Soluble fibers include pectin, inulin and hemicellulose. On the other hand, insoluble fibers do not form gels and don’t ferment as easily. Examples include lignin and cellulose.

The main source of soluble fibers are fruit and vegetables, while grains contain more insoluble fibers. However, most foods with a high fiber content contain a variable amount of soluble and insoluble fibers. Foods with a high fiber content include oats, beans, lentils, chickpeas, chia seeds and most fruit and vegetables.

Fiber and health

An increased fiber intake has been linked to a lower risk of colorectal cancer, small intestine cancer and oral cancer. This anti-carcinogenic effect is achieved through several mechanisms.

When fermented, fiber turns into short-chain fatty acids, which have anti-carcinogenic properties. In addition, fiber controls faecal consistency which lowers the contact time of potential carcinogens and mucous cells. They also encourage the binding of carcinogens to bile salts.

Furthemore, a diet rich in fiber has been linked to a lower risk of cardiovascular disease. Fiber also has a beneficial effect on the prevention and treatment of type 2 diabetes and obesity.

The importance of fiber

The recommended daily dose of fiber is between 25-40 g, depending on the sex and weight of an individual. The average person only consumes about one third of this amount per day. Given the beneficial effect of fiber on the organism in its entirety, it would be ideal to follow a diet full of foods rich in fiber.