Years ago, they said fiber protected against colon cancer. Then it didn't. Now it does again. What's the story?
It's easy to get confused. Blame it on the old scientific method: Someone comes up with a hypothesis, tests it and publishes the results. Other scientists read the results and conduct studies that either support or refute them. Over time, a collective body of scientific studies is built and a consensus among scientists emerges about what's fact and what's fiction.
The fiber story began over 30 years ago, mostly from exam-inations of dietary patterns of people in different countries. In general, people in countries with high fiber intake tend to have lower levels of colon cancer. Nutritionists began advising us to eat more fiber.
Then scientists began testing that hypothesis, and re-testing, and re-testing, using a number of different methods. And, in October 2000, the Food and Drug Administration denied the request of a fiber supplement manufacturer to put on its label, "Consumption of fiber may reduce the risk of colorectal cancer." The reason? According to the FDA, "Based on its scientific review, FDA concludes that the evidence is strong that there is not a relationship between dietary fiber and colorectal cancer." That decision made headlines, and caused many consumers to scratch their heads in confusion.
Now, a new study suggests that foods high in fiber actually might be helpful in reducing colon cancer. The difference? The new study, reported at the American Institute for Cancer Research's International Conference on Food, Nutrition and Cancer, looks at the effect of the whole high-fiber food, not just the fiber from the food. And, it tested levels of phytochemicals -- antioxidants in plant-based foods -- in a new way. Until now, researchers never measured forms of these substances that were bound into the food's cell walls. However, those substances are absorbed into the bloodstream as soon as intestinal bacteria do their job during digestion. As a result, the Cornell University researchers revealed much higher levels of the cancer-fighters in high-fiber foods than ever before.
Does this mean the scientific jury can rest on a higher-fiber, lower-colon-cancer-risk judgment? Hardly. But it does add to the evidence that high-fiber foods can be a healthful addition to your daily diet.
by Martha Filipic
http://extension.osu.edu/~news/story-print.php?id=2943
High-Fiber-Health
Wednesday, November 16, 2005
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