Fiber is both diet fad and fixture for good health—why there is no one‑size‑fits‑all way to increase intake

The numbers paint a clear picture: many Americans are not consuming enough dietary fiber. Numerous studies have linked high-fiber diets to lower risks of cardiovascular disease and colorectal cancer, as well as relief from arthritis symptoms. Despite these benefits, a significant fiber gap remains in the typical American diet. The recommended daily intake is 25 grams for women and 38 grams for men. However, only 4% of U.S. adults met this recommendation between 2013 and 2018, averaging only about 16 grams of fiber per day.

Fiber can be consumed through whole foods like raspberries, avocados, oats, whole grains, and legumes, or through supplements like psyllium husk powder. However, not all fibers are the same. For example, psyllium is viscous and can promote feelings of fullness, potentially aiding in weight loss and improving cholesterol levels. Fermented fibers, like inulin, can lower inflammation in the body by providing nutrients for gut bacteria.

Nutrition experts recommend a variety of fiber-rich foods for overall health benefits, as these also provide other nutrients like antioxidants. Probiotics, found in fermented foods, introduce beneficial bacteria to the gut, but are distinct from the fiber itself. A 2021 study found that a high-fiber diet can enhance the gut microbiome's ability to break down fiber, while fermented foods can increase gut microbiome diversity and lower inflammation.

Despite the benefits, increasing fiber intake can be challenging due to cost, accessibility, and potential discomfort from high-fiber supplements. To improve fiber intake, it's advised to do so gradually and maintain hydration. Experimenting with different fiber sources can help find what works best for each individual. However, more research is needed to determine the optimal types, doses, and combinations of fiber for health benefits.