Do phytosterol reduce risk of heart disease? and more!

By Karen Collins, MS, RD, CDN at American Institute for Cancer Research

Q: Do phytosterols reduce risk of heart disease?

A: Phytosterols, also called plant sterols, are compounds with a chemical structure similar to cholesterol that occur naturally in a variety of plant foods. For people with high blood cholesterol, phytosterols may reduce heart disease risk by decreasing absorption of cholesterol, lowering levels in the blood. Studies show that consuming 2 grams of phytosterols daily can lower LDL (“bad”) cholesterol by about 10 percent. Recently, some research has questioned whether overall heart risk is reduced, but overall recommendations for a cholesterol-lowering strategy do include sterols – or the related compounds called stanols, which have raised no questions. For people with healthy blood cholesterol, phytosterols offer no known benefit for heart health. You can easily accumulate about half a gram (300 to 600 milligrams) of phytosterols from nuts, unrefined vegetable oils, legumes (dried beans and peas), vegetables, fruits and whole grains. Most people are only likely to reach the 2 gram target (2,000 mg) by including two servings of special products such as juices, margarine and salad dressing with extra sterols added. 

Q: Does whey protein increase the risk of prostate cancer?

A: Whey protein is a high quality protein derived from milk. It has become a popular protein supplement among body builders, vegetarians, and cancer patients with diminished appetite. Studies aren't yet clear on whether it may offer additional benefits for people with cancer and other diseases, but research does not suggest that its protein is any better than the protein in other foods. I am not aware of any research linking whey with promoting prostate cancer development. Perhaps you have heard that excessive consumption of milk is a concern. A major report by the American Institute for Cancer Research found that diets high in calcium (above 1500 mg per day) probably increase prostate cancer risk. Avoiding excessive amounts of milk and high doses of calcium is suggested, but moderate amounts of dairy and total calcium no more than 1500 milligrams (mg) daily are considered safe. 

Q: Can people lower their risk of Parkinson’s disease through diet?

A: For now, research provides no solid evidence that antioxidants, caffeine, coenzyme Q10 or other vitamins or supplements can prevent or treat this progressive, incurable disease of nerve cell damage. Some studies suggest that the healthful, plant-based diet already demonstrated to lower risk of cancer and heart disease may provide benefits but data is still preliminary. Some studies suggest that free radicals that damage blood vessels and DNA of our cells might also activate biochemical pathways that damage neurons. People have shown some reduction in risk of the disease when their diets more closely follow a Mediterranean pattern (high in vegetables, low in red meat, fat mostly monounsaturated fat from olives and olive oil). This eating pattern also often includes fish providing omega-3 fat that may be important for brain health. Studies don’t support antioxidant supplements to lower Parkinson’s risk; and though omega-3 fats are part of a diet that promotes overall health, evidence does not show protection from Parkinson’s with high-dose omega-3 supplements.  

Q: What do you suggest for people like me who love high-fat cheese?

A: Regular cheese is high in cholesterol-raising saturated fat – three or four ounces of most full-fat types contain a whole day’s worth – as well as a lot of calories. One strategy is to switch to reduced-fat and low fat varieties; if you don’t like one brand, experiment with others. Another approach is to select regular cheese that delivers more flavor in smaller amounts. A couple teaspoons of freshly grated Parmesan or Romano cheese can add a surprising amount of flavor to salads and baked dishes. When slicing cheese from a block, try using a cheese plane, as Europeans do; it slides along the surface of cheese and results in a thinner slice than most of us can cut with a knife. If you eat cheese as a snack, put a small amount on a plate and eat it slowly as you savor the taste. Then follow it with a pear, apple or other cheese-compatible fruit. Most of us need to boost fruit consumption and by the time you finish, you will probably be full enough that you will not be tempted to go back for more cheese.

Q: Are diglycerides healthy or unhealthy? And what are they?

A: Experts say that diglycerides (also called diacylglycerides or DAGs) are safe and pose no known nutritional risks or benefits as food additives. They are simply a fat molecule missing one of its fatty acid building blocks. Small amounts are used as emulsifiers, thickeners or binders to keep oil from separating out in foods such as peanut butter and salad dressings. Short-term studies suggest that a special oil in which most of the fat is diglycerides instead of the normal triglycerides may cause our body to burn more fat and calories because of the way it processes diglycerides. These fats are sent directly to the liver to be burned instead of circulating through the body. Studies available so far suggest that substituting one to three tablespoons of such an oil for the oil or margarine you use now might produce small amounts of weight loss per year, or prevent the small yearly gains many adults experience. However, we don’t have long-term studies that establish their usefulness for weight control. For now, evidence doesn’t support these oils as any more effective for weight control than a plant-based diet that limits foods concentrated in calories (including oils) along with regular moderate activity.

Q: As a breast cancer survivor, is a food with soy fiber safe for me?

A: Breast cancer survivors are often concerned about soy because of its isoflavone compounds, which are plant forms of estrogen. These plant forms are much weaker than human estrogen. Natural, whole soy foods (such as soy nuts, edamame and tofu) used in moderation may not pose the risk once feared for breast cancer survivors, though some suggest the precaution of limiting these foods to a few servings a week if their cancer was estrogen-positive. Soy fiber does contain isoflavones but the amount in a serving of cereal or bread that contains soy fiber is small. Most experts agree that it is probably safe and possibly beneficial for breast cancer survivors to include up to three servings of soy foods per day. If you are eating soy foods, you may want to check labels to make sure you are limiting added soy and soy fiber in other foods. You could also contact food companies and ask how much soy fiber each serving contains. Doctors often advise people taking anti-estrogen medication to avoid all soy foods during treatment to make sure that even these weak estrogens could not work against anti-estrogen medications. In those circumstances, it may be prudent to avoid or closely limit the number of foods with soy fiber as well. Survivors should discuss this with their physicians.

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The American Institute for Cancer Research (AICR) is the cancer charity that fosters research on the relationship of nutrition, physical activity and weight management to cancer risk, interprets the scientific literature and educates the public about the results. It has contributed more than $87 million for innovative research conducted at universities, hospitals and research centers across the country. AICR has published two landmark reports that interpret the accumulated research in the field and is committed to a process of continuous review. AICR also provides a wide range of educational programs to help millions of Americans learn to make dietary changes for lower cancer risk. Its award-winning New American Plate program is presented in brochures, seminars and on its Web site, www.aicr.org. AICR is a member of the World Cancer Research Fund International.

Publication Date: September 7, 14, 2009 Contact: Alice Bender, (202) 328-7744