A large epidemiologic study by researchers at Harvard published in the New England Journal of Medicine this month has confirmed previously published findings about the health benefits of eating nuts in combating chronic health diseases and in reducing deaths from all causes, especially when consumed several times a week.

In the Nurses Study and the Health Professionals Follow Up Study, investigators took frequent self-reported histories of nut consumption from over 76,000 women and 42,000 men and followed them up for an equivalent of over 3 million life years. A striking dose response was demonstrated when comparing persons who ate nuts with those who did not after controlling for potential confounding factors. The benefits in death reduction ranged from a low of 7% for those who consumed nuts less than once a week to 20% for those who consumed nuts 7 or more times per week. Nuts were also shown to be beneficial for reducing the risk of death against cancer, heart disease, and respiratory disease. Results were similar for peanuts and tree nuts.

According to Ying Bao and colleagues, “We cannot rule out the possibility of confounding by unknown factors…a potential confounding effect would have to be quite large to meaningfully alter the observed associations in this study…it seems unlikely that such strong unmeasured confounding could explain the associations.” They identified the prospective design, large sample, and 30 years of follow-up with a high follow-up rate and repeated assessments of diet and lifestyle variables as strengths of the study.

In a an entertaining video feature called Quick Take on the NEJM website, the NEJM editor seeks to explain the findings of the study and their significance for the average person. Readers of the Epidemiology Monitor can imagine some of the ridicule these findings might engender on late night TV shows and elsewhere because of epidemiology’s reputation for controversial and sometimes contradictory findings on the risks or benefits of a wide variety of diet and other lifestyle factors. The video is a well-executed example of how scientific findings in epidemiology can be disseminated to both a lay and a professional audience and seeks to address some of the questions listeners may have. For example, this is how the video concludes:

“If you include nuts in your regimen of sloth and gluttony, will you live longer than if you left nuts out? These kind of data can’t answer that question, but I would be nuts if I were to think that eating nuts alone would add years to my life.”

Watch the video at:
http://tinyurl.com/jvtad2s  ■

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