Fiber Does A Lot More than Prevent Constipation

It seems like every day scientists discover more ways in which eating whole, unprocessed food prevents disease. For example, researchers at the University of Illinois recently found that when they fed the fiber pectin (found in whole fruit, especially apples, citrus and plums) to mice, it greatly increased the mice’s ability to respond to an immune challenge. In other studies, getting adequate dietary fiber has been shown to lower cholesterol as well as the risk of heart disease, diabetes, diverticulosis and obesity, and to protect against cancer through a variety of mechanisms, including providing food for beneficial bacteria in the gut. In one study, women who increased their fiber intake to 30-35 grams a day and maintained it for a year reported 60% less constipation and 30% less heartburn.

Yet the modern diet minimizes whole foods that provide fiber – fruits, vegetables, nuts, seeds, grains, beans and legumes. As a result, although the U.S. Institute of Medicine recommends 28-35 grams of fiber daily, it’s been estimated that the average American gets only 5-15 grams a day. Our healthy ancestors probably got more like 40-60 grams a day.

No wonder laxative sales have never been better! And disease risk for heart disease, obesity and cancer never been higher!

Remember that sugar, animal proteins and fat of any kind provide no fiber at all; nor do soft drinks, which, as reported recently in Environmental Nutrition, are now the single largest contributor of calories in the US. Cooking, refining and juicing all reduce fiber (although pureeing in a VitaMix has a negligible effect on fiber).

However, getting enough fiber is quite easy if you eat a plant-based diet including 10-12 servings of fruits and vegetables daily, mostly raw, whole grains, nuts, seeds, and especially beans and legumes. Beans and legumes are especially high in fiber: a cup of cooked split peas, lentils, or black beans will each provide more than 15 grams!

Warning: Transitioning from a low to a high-fiber diet can entail uncomfortable gas, bloating and even constipation, unless you increase fiber gradually (some experts say about 5 grams per week) and make sure to drink lots of water.

Sherry CL. "Sickness behavior induced by endotoxin can be mitigated by the dietary soluble fiber, pectin, through up-regulation of IL-4 andTh2 polarization." Brain, Behavior and Immunity. May 2010;24:631-640.

Study reported in the Tufts University Diet and Nutrition Letter. "Eating more fiber doesn’t have to be uncomfortable." July 2002;20(5):7

Environmental Nutrition. Research News: "Drink water, coffee, and tea instead of sugary beverages." April 2012;35(4):3.