Just like dietary fat, fiber may influence your circulating estrogen levels. Although most of the research on fiber intake and estrogen levels has focused on breast cancer risk, the findings may be relevant to fibrocystic breast conditions. There have been a few recent studies that show higher-fiber diets reduce estrogen levels in the body. Two studies conducted in premenopausal women suggest that diets high in wheat bran are effective in lowering circulating estrogen. In one study, both a 10- and 20-gram wheat bran supplement significantly lowered estrogen after four weeks.2 The total fiber intake of these women was between 20 and 32 grams.
Scientists think that fiber may work through its ability to bind estrogen in the intestinal tract, making the hormone less available for absorption into the bloodstream. High-fiber diets cause more estrogen to be excreted. Boosting your fiber intake may also change the acidity of your intestinal tract, slowing the activity of the bacterial enzymes that make estrogen ready for absorption.
Wheat bran belongs to a class of fibers referred to as insoluble. That means they are unable to dissolve in water. They pass through the intestinal tract intact and, in the process, they are able to bind compounds including estrogen. Soluble fibers found in oatmeal, oat bran, dried beans, lentils and psyllium-enriched breakfast cereals also have this ability, even though it has not been specifically studied for its effect on estrogen levels.
It’s estimated that Americans eat on average 14 grams of fiber per day—not quite the 20 to 32 grams that may lower estrogen levels. You certainly don’t need to rely on a fiber supplement to get more wheat bran into your daily diet. All it takes is a bowl of high-fiber breakfast cereal each morning.
See the Fiber in Foods table on page 29 of chapter 1 for more high-fiber foods. Use the list to gradually add higher-fiber foods to your diet. Too much fiber too soon can cause bloating, gas and diarrhea, so spread fiber-rich foods out over the course of the day. And don’t forget that fiber needs fluid to work, so drink at least 8 ounces of fluid with each high-fiber meal and snack.
Soy Isoflavones for Fibrocystic Breast Conditions
As is the case with fat and fiber, the research findings on soy intake and estrogen levels provide indirect evidence that soy foods may possibly be beneficial in preventing fibrocystic breast conditions. Many studies have found that a diet rich in soy foods lowers the level of circulating estrogen in women. Soybeans contain natural chemicals called isoflavones, a class of plant compounds that have weak estrogen activity in the body. One of the main isoflavones in soybeans, called genistein, is able to compete with a woman’s own estrogen for binding to estrogen receptors. In so doing, soy isoflavones are able to reduce the amount of estrogen that contacts breast cells.
Most of the studies looking at how soy isoflavones behave in breast cells have been done in the laboratory. And they have been conducted in the hopes of finding a link to preventing breast cancer, not fibrocystic breast conditions. Despite this, the findings do suggest that a regular intake of soy can lower circulating estrogen. And this may help prevent fibrocystic breast symptoms. As you will read throughout this blog, soy foods have potential for helping women in a number of ways. Soy may lower blood cholesterol, slow down bone loss, reduce menopausal hot flashes and reduce your risk of breast cancer if you start eating it at a young age. So you can see there are other good reasons to start incorporating this food into your diet. Here are a few ideas to help you get started:
• Pour a calcium-fortified soy beverage on breakfast cereal or in a smoothie, and use in cooking and baking (soups, casseroles, muffins, pancake batters).
• Cube firm tofu and add it to soups—canned or homemade.
• Grill firm tofu on the barbecue. Brush tofu and vegetable kebabs with hoisin sauce or marinate them in teriyaki sauce.
• Substitute firm tofu for ricotta cheese in recipes.
• Use soft tofu in creamy salad dressing or dip recipes.
• Throw canned soybeans in a salad, soup or chili.
• Replace up to one-half of all-purpose flour in a recipe with soy flour.
• Buy roasted soy nuts in health food stores. They come in plain, barbecue, gar- lic or onion flavors. Enjoy 1/4 cup (60 ml) as a mid-day snack.
• Toss roasted soy nuts in a green salad.
• Replace ground meat with TVP (texturized vegetable protein) in chili, pasta sauce and tacos.