Dr. D Aune, a nutritional epidemiologist from the Imperial College in London was the lead author in the paper published in Annals of Oncology http://annonc.oxfordjournals.org/content/early/2012/01/10/annonc.mdr589.full.pdf. They reviewed 16 prospective studies of dietary fiber intake and breast cancer risk.
They found that there was a 5% decrease in the numbers of breast cancers for each 10gm of fiber women eat each day.
So what is fiber and which is best. There is not just one dietary fiber. Many of us were taught that fiber was the outer layer of grains and skin of fruits and root vegetables, which just passed on through; but now we understand that there are two kinds of dietary fiber: soluble and insoluble.
Soluble fibers are mostly carbohydrates that dissolve in water to make a gel in the stomach to slow digestion and make us feel full. Examples of soluble fibers include oatmeal, fruits, nuts, and legumes (beans and peas). These kinds of fiber slow digestion and produce favorable effects on glucose, insulin and cholesterol.
Insoluble fibers are plant cell walls that don't dissolve in water and are considered gut-healthy because they have a laxative effect by adding bulk and passing through relatively intact. Examples are whole wheat, wheat bran, whole grains, seeds, some dark leafy vegetables and the skin of fruits and root vegetables.
The review examined papers including fruit fiber, vegetable fiber, cereal fiber and soluble versus insoluble fibers. Dietary soluble fiber showed the greatest inverse relationship with breast cancer.
Dietary fiber may lead to fewer breast cancers by several mechanisms. The fiber decreases absorption of estrogens by reducing the activity of an enzyme necessary for the process. Fiber binds estrogen and increases excretion. Fiber reduces insulin over secretion by delaying gastric emptying and increasing small bowel transit time. High fiber diets may also reduce obesity, but in studies controlled for weight, the breast cancer reduction was still present (independent of weight).
Dietary fiber may lead to fewer breast cancers by several mechanisms. The fiber decreases absorption of estrogens by reducing the activity of an enzyme necessary for the process. Fiber binds estrogen and increases excretion. Fiber reduces insulin over secretion by delaying gastric emptying and increasing small bowel transit time. High fiber diets may also reduce obesity, but in studies controlled for weight, the breast cancer reduction was still present (independent of weight).
Recommended amounts of daily fiber intake vary from 20 to 35 grams per day.
Now we can figure out how much fiber we eat by looking at the Nutrition Facts label on most foods. Dietary fiber is found just under total carbohydrates. Or check out www.nal.usda.gov/fnic/foodcomp/search/. For example: one medium apple has 4 grams of fiber, one medium banana has 3 grams, one cup beans has 10-15 grams and one tablespoon of wheat bran has 12 grams.
So let's eat our way to fewer breast cancers with more dietary fiber.
Now we can figure out how much fiber we eat by looking at the Nutrition Facts label on most foods. Dietary fiber is found just under total carbohydrates. Or check out www.nal.usda.gov/fnic/foodcomp/search/. For example: one medium apple has 4 grams of fiber, one medium banana has 3 grams, one cup beans has 10-15 grams and one tablespoon of wheat bran has 12 grams.
So let's eat our way to fewer breast cancers with more dietary fiber.
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