Fiber Supplement May Hurt, Not Help Study finds potential cancer risk By Edward Edelson HealthScout Reporter THURSDAY, Oct. 12 (HealthScout) -- A European study raises a warning about fiber supplements: They don't protect against colon cancer and may do some harm. A 10-nation study finds that supplements containing an unusual source of fiber increased the recurrence of adenomas, growths in the colon that can become cancerous, reports the European Cancer Prevention Organization Study Group in the Oct. 14 issue of The Lancet. "In our opinion, this study indicates that supplementation is not needed, and that a person should continue to eat a diet rich in vegetables to obtain fiber," says Dr. Claire Bonithon-Kopp, a surgical gastroenterologist at Odense University Hospital in Denmark and a member of the study group. "The overall recommendations for a healthy diet by the American Cancer Society and other health organizations aren't being changed because of these findings," says Dr. Michael Thun, vice president for epidemiology of the society. "We still recommend a diet rich in plant foods, limited fat consumption, maintenance of optimal body weight and if you drink, drinking in moderation." This is the fourth study to find no benefits for dietary fiber supplements in preventing colon cancer, Thun says. The other studies involved wheat-bran fiber. The European group says it used ispaghula husk because it was effective in preventing colon cancer in animal tests and is widely used as a laxative. In the study, 665 patients with a history of colon adenomas were given the fiber supplement, a calcium supplement or a placebo. They underwent colonoscopy after three years to detect any new adenomas. Calcium supplements were associated with "a modest but not significant reduction in the risk of adenoma recurrence," the researchers say -- a 16 percent recurrence rate compared to 20 percent for those receiving the placebo. But the recurrence rate was 29 percent in the fiber supplement group. May be specific fiber "It is not possible to say with our results that fiber supplements promote adenoma growth," Bonithon-Kopp says. "It is possible that only this specific fiber has that effect." An editorial accompanying the article, written by Dr. Bernard Levin of the University of Texas's M.D. Anderson Cancer Center, says evidence is mounting against fiber's beneficial effect. "Despite some limitations of this study, it seems likely from this report and other recent trials that supplementation with dietary fiber is not of benefit in preventing recurrence of colorectal adenoma," he writes. A large-scale American study using wheat-bran fiber, the Polyp Prevention Trial, reported negative results -- but no adverse effects -- in April. It also involved patients who had developed adenomas and found that a high-fiber diet, with or without supplements, did not reduce the rate of recurrence. The recurrence rate for the high-fiber group was very slightly higher, 39.7 percent compared with 39.5 percent for the group that did not increase fiber intake, a difference that had no statistical significance. All the results don't change the existing eating rules because "our dietary recommendations concern fruits and vegetables, not supplements," Thun says. "The data showing lower risk for conditions such as heart disease all come from foods, not supplements. Those data show a broad range of benefits from a proper diet." The American Cancer Society's advice on colorectal cancer emphasizes early detection, with regular fecal occult blood tests, sigmoidoscopies and colonoscopies for persons 50 and older and at earlier ages for those with a family history of colon cancer. The European study has a significance that goes beyond its immediate findings, Thun says. "This is the appropriate way for nutritional science to proceed, with carefully controlled trials. Health claims about supplements and nutrition need to be tested rigorously. Just because something is natural doesn't mean that it is beneficial," he says. What To Do Anyone over age 50 or at high risk for colon cancer should have examinations once a year, and everyone should eat a diet high in fiber, fruits and vegetables to reduce the risk of heart disease, stroke and some forms of cancer. The U.S. Department of Agriculture recommends eating 20 to 35 grams of fiber a day. Half a cup of bran flakes has 5.5 grams; a pear has 4.5 grams. The American Dietetic Association also has tips on eating right. Lancet, 10/02 Remember we are NOT Doctors and have NO medical training. This site is like an Encylopedia - there are many pages, many links on many topics. Support our work with any size DONATION - see left side of any page - for how to donate. You can help raise awareness of CAM.