“I read that fiber interferes with the absorption of vitamins and minerals. Is that true?”
Assuming that you’re not taking some sort of “cleansing” product designed specifically to “bind” to certain nutrients, the answer is, “No.” Think about it for a moment and this will make sense. If fiber really interfered with nutrient absorption, wouldn’t people who ate a lot of whole grain breads be deficient in those nutrients? And how could you absorb the nutrients from vegetables?
What Science Says
A 1989 study authored by the Committee on Diet and Health, National Research Council devoted an entire section to dietary fiber and found that, at least as far as we know now, regular dietary fiber does not seem to impede nutrition or interfere with the way your body absorbs or uses vitamins and minerals.
There seems to be some association between diets high in unleavened whole-wheat bread and vitamin-D-associated rickets but this phenomenon isn’t present in all populations. There is absolutely no evidence that regular dietary fiber interferes with mineral absorption. (You can read the complete report free online at the National Academies Press web site.)
Still Worried About Fiber Interfering With Your Vitamins & Minerals?
If you take dietary fiber supplements and this issue worries you, just take your supplements away from meals. You’ll still get the potential health benefits of a little extra fiber and you’ll minimize your risk of impeding your body’s use of other nutrients.
Committe on Diet and Health, National Research Council. (1998). Diet and Health: Implications for Reducing Chronic Disease Risk.