food and nutrition


Plant Sterol

Question: How effective are plant sterol esters in reducing cholesterol? I've seen nutritional supplements that have plant sterol esters (I think I'm getting the terms right here), like soybean oil, that claim to help reduce cholest. But, you have to take a lot of it (preferrably before a meal) and I'm wondering how much this stuff really helps. (I know that a low-fat and high-fiber diet and excersise are far more important, but I'm wondering if there are other things I can do to help the bad cholesterol down). I'm suspicious of these supplements -- they're expensive and you have to take them a lot. Any advice? R

Answer: The general answer is that plant sterols alone can lower LDL (bad) cholesterol by as much as 15% without affecting HDL (good) cholesterol levels. Whether this is enough to achieve the target LDL levels for each of us depends on a range of factors. And the general wisdom is that plant sterols are more effective when taken in fortified foods as opposed to supplements. Plants produce plant sterols. Animals produce cholesterol. Structurally similar, both bind to sites in our intestines where the cholesterol produced in our livers and consumed in our foods are absorbed into our blood. Yet, our bodies have evolved the ability to distinguish between these types of sterols. On average, we absorb about 55% of cholesterol and less than 1% of the plant sterols. Plant sterols work to lower cholesterol by filling the "absorption gateways," thus blocking the cholesterol from entering the blood stream. Blocked cholesterol is execreted along with most of the plant sterols. In nature, small quantities of plant sterols can be found in a range of foods, particularly vegetable oils (sources of plant sterols). The average plant sterol intake in the U.S. is about 250 milligrams. Vegetarians consume in a range of 400 to 750 milligrams. Plant sterol intake in traditional diets has been estimated to be about 1g (1000mg). Medical studies have concluded that 2-3g (2000-3000mg) effectively lower cholesterol. Fortified foods are typically required to obtain these levels. The effectiveness of plant sterols will vary from person-to-person. Many people absorb cholesterol more effectively than others. For these individuals, the impact of plant sterols may be more significant. Overall, plant sterols are an important component of a nutritional system designed to promote healthier cholesterol and blood lipid levels. Achieving maximum benefits from natural cholesterol management may require other nutrients---including the soluble fibers found in oats, beans, fruit and psyllium, certain types of niacin, Omega-3s, monounsaturated fats in place of saturated fats----all in the context of balanced nutrition, calorie-mindfulness and physcial activity. A recent study, published in Food & Nutrition Research (January 2009), found that while sterols uniformly worked to lower LDL cholesterol, their power is affected by a number of factors. The study assessed 59 randomized clinical trials published from 1992 to 2006. Maximum results were found where patients: Consumed 2.5 grams of sterols or stanol per day. The FDA allows a health claim for products containing as little as .4 grams of plant sterols or .65 grams of plant sterol esters. As such, individuals will often need to take multiple servings of plant sterol products to attain the optimum daily intake. Consumption beyond 2.5 grams did not lead to further reductions ( Foods with Plant Sterols). Took plant sterols over the course of the day. Multiple servings were generally found to be more effective than a single serving. Not surprising, sterols lowered LDL cholesterol by more among individuals with high or very high cholesterol levels, but sterols also proved effective among individuals with optimal to borderline-high LDL cholesterol. The authors also sought to assess the power of sterols across different types of foods. While they generally found that foods with some fat content (greater than 3 grams per serving) and low-fat milks and yogurts may be somewhat better, the evaluation does not appear to control for other elements of diet, lifestyle and medications. More research in the role of plant sterols coupled with a broader approach to therapeutic nutrition for cholesterol management is merited.


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