People who regularly eat nuts, including peanuts, walnuts and tree nuts, may have a lower risk of developing cardiovascular disease or coronary heart disease compared to people who never or almost never eat nuts, according to a study published Nov. 13 in the Journal of the American College of Cardiology. The study is the largest to date looking at frequency of nut consumption in relation to incident cardiovascular disease.

Marta Guasch-Ferre, PhD, et al. looked at over 210,000 people, including women from the Nurses' Health Study and Nurses' Health Study II and men from the Health Professionals Follow-up Study, with up to 32 years of follow up. In all three groups, information about medical history, lifestyle and health conditions were collected via self-administered questionnaires every two years.

The researchers documented 14,136 cardiovascular disease cases, including 8,390 coronary heart disease cases and 5,910 stroke cases. They found a consistent inverse association between total nut consumption and total cardiovascular disease and coronary heart disease. Also, after looking at individual nut consumption, eating walnuts one or more times per week was associated with a 19 percent lower risk of cardiovascular disease and 21 percent lower risk of coronary heart disease. Participants who ate peanuts or tree nuts two or more times per week had a 13 percent and 15 percent lower risk of cardiovascular disease, respectively, and a 15 percent and 23 percent, lower risk of coronary heart disease, respectively, compared to those who never consumed nuts.

Participants who consumed five or more servings of nuts a week had a 14 percent lower risk of cardiovascular disease and a 20 percent lower risk of coronary heart disease than participants who never or almost never consumed nuts. The results were similar when accounting for consumption of tree nuts, peanuts and walnuts individually. Researchers found no evidence of an association between total nut consumption and risk of stroke, but eating peanuts and walnuts was inversely associated with the risk of stroke. Peanut butter and tree nuts were not associated with stroke risk.

Several limitations were noted in the study, including that the sample size was limited to white health professionals. However, the researchers note that the results can be generalized to men and women of different ethnicities because there is no reason to expect the underlying mechanisms to be different. Also, because the nut intake was self-reported, errors are inevitable, and there was not data on how the nuts were prepared, so the influence of preparation methods was not able to be tested.

In an accompanying editorial comment, Emilio Ros, MD, PhD, of the Endocrinology and Nutrition service at the Hospital Clínic in Barcelona and investigator of CIBEROBN, a research network of Instituto de Salud Carlos III, Spain, explains the findings strongly suggests an association between nut consumption and heart disease protection, but that there is more to research.

"Ideally, further investigations should test the effects of long-term consumption of nuts supplemented into the usual diet on hard cardiometabolic events," Ros said. "In the meantime, raw nuts, if possible unpeeled and otherwise unprocessed, may be considered as natural health capsules that can be easily incorporated into any heart-protective diet to further cardiovascular well-being and promote healthy aging."

Keywords: Nuts, Juglans, Follow-Up Studies, Research Personnel, Sample Size, Self Report, Capsules, Spain, Diet, Eating, Risk, Life Style, Heart Diseases, Coronary Disease, Cardiovascular Diseases, Stroke, Epidemiologic Studies

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