The eating habits of over 86,000 nurses, aged 34-59, were followed for ten years. “Women who frequently ate about an ounce of nuts, including peanuts, lowered their risk of heart disease by about a third, compared to women who rarely ate nuts” said Dr. Frank Hu, principal investigator of the study. It is estimated that peanuts and peanut butter comprised more than half of the nuts eaten.
In an editorial in the same issue of the BMJ, Dr. Hugh Tunstall-Pedoe at the Cardiology and Epidemiology Unit, University of Dundee, observes “that the effect (of eating nuts, including peanuts) appears large and significant, as great or greater that that in statin trials.” The statin family of drugs helps to reduce blood cholesterol levels.
The importance of eating nuts remained strikingly strong even when adjustments in the data were made for other variables such as age, smoking, eating fresh fruits and vegetables, exercise, and intake of vitamin supplements.
This data in the Nurses Study is supported by the Physicians Health Study that was reported last week in Dallas, Texas at the American Heart Association Conference. In the Physicians Health Study, a prospective 12 year study involving over 22,000 male physicians, data showed that as nut consumption increased the risk of total cardiac death and sudden death decreased.
The Harvard Nurses Study underscores the fact that some higher fat foods are good for you and should become a part of the daily diet. Many people are overly focused on counting fat grams. As a result, they are missing out on the healthy benefits of good monounsaturated fats, like those found in peanut products and olive oil.
In a recent study at Pennsylvania State University subjects who made small changes in their diet reduced their cholesterol levels by more than 10-14 percent within a month. This was achieved by using peanut butter on a bagel instead of butter or cream cheese and substituting peanuts (about 15) for other snack foods. Subjects who used olive oil as a prominent source of fat in their diet had similar results.
The Harvard study also found that “women who frequently consumed nuts were leaner than women who rarely consumed nuts.” A recent study at Purdue University showed that higher fat foods like peanuts and peanut butter were more satisfying than a high carbohydrate snack, like rice cakes. The peanut-eaters felt full sooner, self adjusted their caloric intakes, and did not add extra calories to their daily diets.
Peanuts and peanut butter contain numerous constituents that may contribute to these protective benefits. In addition to heart-healthy monounsaturated fat, peanuts contain plant protein, vitamin E, fiber, folic acid, magnesium, copper, potassium, and many other hard to get nutrients. Peanuts contain more arginine than any other nut. This plant protein is a precursor to nitric oxide, a chemical which expands blood vessels and inhibits the build-up of cells that can clog blood vessels.
Peanuts also contain resveratrol, a plant chemical also found in red wine, which studies have shown to have a protective effect against cancer and heart disease. Research done at the University of Illinois shows resveratrol to be one of the most potent phytochemicals. The folate (folic acid) found in peanuts is thought to reduce homocysteine levels in the blood, another risk factor for coronary heart disease. Peanuts contain the antioxidant vitamin E, which has been associated with a lower risk of heart disease. And, since they are a plant food, peanuts naturally contain no cholesterol.
The Peanut Institute is a non-profit organization that supports nutrition research and develops educational programs to encourage healthful lifestyles.