Results from an analysis of 64 studies with a total of more than 3 million participants supported prior findings that dietary fiber intake is associated with better health. People who reported higher consumption of dietary fiber were significantly less likely to die from cardiovascular disease, cancer, or other causes during the study period.
Fiber is found naturally in plant foods, including whole grains, fruits, vegetables, legumes, nuts, and seeds. It can be categorized as soluble or insoluble. Soluble fiber forms a gel with water; insoluble fiber does not. In this study, insoluble fiber was more significantly associated with lower risk of death than soluble fiber. Foods that contain fiber almost always have a mixture of the two types, although wheat bran, whole grains, fruits (with the skin, when edible, and many vegetables (including turnips, green peas, okra, sweet potatoes, and kale) are particularly high in insoluble fiber.
Processing can reduce or eliminate naturally present fiber, such as fruit juice vs whole fruit, and white flour vs whole grain flour. Naturally high in fiber, whole and minimally processed plant foods also contain other beneficial nutrients (vitamins, minerals, and phytochemicals) that contribute to good health.