A study published in the Journal of the American College of Cardiology indicates that people who regularly eat nuts—including peanuts, walnuts and tree nuts (eg. Brazil nuts)—have a lower risk of developing cardiovascular disease or coronary heart disease compared with those who never or almost never eat nuts. The study is the largest to date looking at frequency of nut consumption in relation to incident cardiovascular disease.
Marta Guasch-Ferre (Harvard T.H. Chan School of Public Health, USA) and colleagues reviewed more than data for 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.
While many past studies have focused on nut consumption as a whole, this study also looked at the association between specific types of nuts—peanut butter, peanuts, walnuts and tree nuts—with major cardiovascular events. Peanuts were included even though they are actually a legume because they have a similar fatty acid and nutrient profile as other nuts.
The primary endpoint was major cardiovascular disease, defined as a combined endpoint of myocardial infarction, stroke or fatal cardiovascular disease. Secondary endpoints were total coronary heart disease, defined as fatal or non-fatal myocardial infarction, and total stroke, which included all fatal and non-fatal strokes. Researchers documented 14,136 cardiovascular disease cases, including 8,390 coronary heart disease cases and 5,910 stroke cases.
The study found a consistent inverse association between total nut consumption and total cardiovascular disease and coronary heart disease. Also, after looking at individual nut consumption, the investigators found that eating walnuts one or more times per week were associated with a 19% lower risk of cardiovascular disease and 21% lower risk of coronary heart disease. Participants who ate peanuts or tree nuts two or more times per week had a 13% and 15% lower risk of cardiovascular disease, respectively, and a 15% and 23%, 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% lower risk of cardiovascular disease and a 20% 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. Guasch-Ferre et al 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.
Guasch-Ferre says: “Our findings support recommendations of increasing the intake of a variety of nuts, as part of healthy dietary patterns, to reduce the risk of chronic disease in the general populations.”