Peanuts: Natures Defence Against Heart Disease

Peanuts are rich in monounsaturated fats, the type of fat that is emphasized in the heart-healthy Mediterranean diet. Studies of diets with a special emphasis on peanuts have shown that this little legume is a big ally for a healthy heart. In one such randomized, double-blind, cross-over study involving 22 subjects, a high monounsaturated diet that emphasized peanuts and peanut butter decreased cardiovascular disease risk by an estimated 21% compared to the average diet.

In addition to their monounsaturated fat content, peanuts feature an array of other nutrients that, in numerous studies, have been shown to promote heart health. Peanuts are good sources of vitamin E, niacin, folate, protein and manganese. In addition, peanuts provide resveratrol, the phenolic antioxidant also found in red grapes and red wine that is thought to be responsible for the French paradox: the fact that in France, people consume a diet that is not low in fat, but have a lower risk of cardiovascular disease.

Not only do peanuts contain oleic acid, the healthful fat found in olive oil, but new research shows these tasty legumes are also as rich in antioxidants as many fruits. While unable to boast an antioxidant content that can compare with the fruits highest in antioxidants, such as pomegranate, roasted peanuts do rival the antioxidant content of blackberries and strawberries, and are far richer in antioxidants than apples, carrots or beets.

Research published in the British Journal of Nutrition (Blomhoff R, Carlsen MH), which identified several nuts among plant foods with the highest total antioxidant content, suggests nut's high antioxidant content may be key to their cardio-protective benefits. Nuts' high antioxidant content helps explain results seen in the Iowa Women's Health Study in which risk of death from cardiovascular and coronary heart diseases showed strong and consistent reductions with increasing nut/peanut butter consumption.

Even more impressive were the results of a review study of the evidence linking nuts and lower risk of coronary heart disease, also published in the British Journal of Nutrition. (Kelly JH, Sabate J.) In this study, researchers looked at four large prospective epidemiological studies—the Adventist Health Study, Iowa Women's Study, Nurses' Health Study and the Physician's Health Study. When evidence from all four studies was combined, subjects consuming nuts at least 4 times a week showed a 37% reduced risk of coronary heart disease compared to those who never or seldom ate nuts.

Resveratrol is a flavonoid first studied in red grapes and red wine, but now also found to be present in peanuts. In animal studies on resveratrol itself (the purified nutrient given in intravenous form, not the food form), this phytonutrient has been determined to improve blood flow in the brain by as much as 30%, thus greatly reducing the risk of stroke, according to the results of a laboratory animal study published in the Journal of Agricultural and Food Chemistry.

The jury is still out on peanuts however, since they contain far less resveratrol than the amounts used in the above study, and also less than the amount provided by red wine. An ounce of red wine can provide as much as 1,000 micrograms of resveratrol, and it almost always provides over 75 micrograms. The same ounce of peanut butter can only provide about 50 micrograms of resveratrol. Still, routine consumption of peanuts or peanut butter might turn out to be significant in terms of the resveratrol provided by this food.

A number of studies have shown that nutrients found in peanuts, including folic acid, phytosterols, phytic acid (inositol hexaphosphate) and resveratrol, may have anti-cancer effects. A rich source all these nutrients—including the phytosterol beta-sisterol, which has demonstrated anti-cancer actions—peanuts have long been considered a likely candidate as a colon cancer-preventive food.

Colorectal cancer is the second most fatal malignancy in developed countries and the third most frequent cancer worldwide. In Taiwan, not only has incidence of colon cancer increased, but the likelihood of dying from the disease rose 74% from 1993 to 2002. Taiwanese researchers decided to examine peanuts' anti-colon cancer potential and conducted a 10-year study involving 12,026 men and 11,917 women to see if eating peanuts might affect risk of colon cancer. Risk of colon cancer was found to be highly correlated with both peanuts, which greatly lessened risk, and pickled foods, which greatly increased risk, particularly in women.

Twenty years of dietary data collected on over 80,000 women from the Nurses' Health Study shows that women who eat at least 1 ounce of nuts, peanuts or peanut butter each week have a 25% lower risk of developing gallstones. Since 1 ounce is only 28.6 nuts or about 2 tablespoons of nut butter, preventing gallbladder disease may be as easy as packing one peanut butter and jelly sandwich (be sure to use whole wheat bread for its fiber, vitamins and minerals) for lunch each week, having a handful of peanuts as an afternoon pick me up, or tossing some peanuts on your oatmeal or salad.

Categories: Food And Nutrition