Does High Fiber Intake Interfere With Absorption Of Vitamins And Minerals?

The federal Dietary Guidelines for Americans recommend choosing more foods that contain dietary fiber, including fruits, vegetables and whole grains. High fiber intake protects against constipation, diverticular disease, cardiovascular disease and type 2 diabetes. However, research has been mixed on whether fiber could have an adverse effect on the body's ability to absorb nutrients.

Cereal Fiber

According to a report published in 1999 in the "Journal of Nutrition," cereal fiber has been shown to decrease the absorption and retention of calcium, magnesium and zinc during the same meal. It is believed, however, that phytates -- inositol, or vitamin B8 -- decreased absorption instead of fiber. The size of the fiber particles and amount of minerals also had an impact on absorption.

Pectin and Guar Gum

The addition of pectin and gums in food generally does not decrease mineral absorption, except for magnesium, according to the Linus Pauling Foundation. However, a study of women published in 1999 in the "Journal of Nutrition" found that water-soluble dietary fiber, such as pectin and gums, decreased absorption of beta-carotene, lycopene and lutein According to the previous section's journal report, pectin has been shown to increase iron absorption.

Inulin and Oligofructose

Nondigestible oligosaccarides, such as inulin and oligofructose, have been found to increase absorption of some minerals. In a review of animal studies published in the "Journal of Nutrition" in 2007, it was noted that several minerals and trace elements, including calcium, magnesium, phosphorus, copper, zinc and iron were absorbed more readily in the presence of these dietary fibers. The study noted that inulin could help improve the supply of calcium in the body and improve bone health.

Considerations

While some types of fiber might decrease absorption of some vitamins and minerals, the Linus Pauling Institute reports fiber has not been shown to adversely affect nutrient status in healthy people consuming recommended levels of fiber, between 21 and 38 g per day. Due to the benefits provided by fiber, it is important to get adequate fiber unless otherwise directed by your health care provider.