Question: I know it’s important to get enough fiber to help with constipation, but I’ve also read that it can help prevent disease. How does that work?
Answer: New research is coming out all the time about the health benefits of a high-fiber diet, and, you’re right, they go way beyond helping to keep you “regular.”
Unfortunately, most Americans consume only about 10 to 15 grams of fiber a day. The recommendation for adults under 50 is 25 grams a day for women and 38 grams for men. Those over 50 should get 25 grams a day for women and 30 for men — still much higher than the average.
Studies have long associated high-fiber diets with a reduced risk of heart disease and diabetes, but two recent studies show even more benefits:
A Harvard University study published in Pediatrics indicates that young women who eat the most fiber have a lower risk of breast cancer later in life. The researchers believe fiber helps reduce high estrogen levels in the blood, which are one cause of breast cancer. The reduced risk was significant: For each additional 10 grams of daily fiber intake as a young adult, risk dropped by 13 percent. Fiber from fruits and vegetables seemed to have the greatest effect.
A recent University of Nebraska study indicates a high-fiber diet could reduce the risk of lung disease. Researchers studied data from people 40 to 79 years old and found that for those who had the highest fiber intake (at least 18 grams a day), 68 percent had normal lung function and only 15 percent had airway restrictions. For those with the lowest fiber consumption, only 50 percent had normal lung function and 30 percent had airway restrictions. Researchers believe that fiber’s role in reducing inflammation throughout the body may play a role in helping the lungs. In addition, studies have shown that a high-fiber diet changes the microflora in the gut, which could reduce infections and, researchers speculate, may release lung-protective chemicals in the body.
Eating an ample amount of high-fiber foods should provide plenty of both soluble and insoluble types of fiber, both of which provide benefits.
Soluble fiber dissolves in water and forms a gel, which can help prevent fats and sugars from being absorbed by the body, reducing blood cholesterol and glucose levels. Some studies indicate high soluble fiber intake can reduce the risk of coronary artery disease and stroke by 40 to 50 percent.
Insoluble fiber, which comes from a plant’s cell walls, provides bulk to stools, helping prevent constipation, hemorrhoids and chronic diarrhea, and helps with digestion.
To increase fiber intake, eat five to six servings of fruits and vegetables a day, along with a couple of servings of whole grains or legumes. A serving includes a medium-sized fruit; a half-cup of fruit, most vegetables, beans, whole-grain pasta or brown rice; a cup of raw leafy greens; or a slice of 100 percent whole-wheat bread.
For more on fiber, see the National Institutes of Health web page, www.nlm.nih.gov/medlineplus/dietaryfiber.html.