Eating peanuts more than three times a week reduces overall mortality

Written by Dr. Andrew Craig, APC Health Consultant

Peanuts together with some tree nuts (almonds, hazelnuts, walnuts, pistachios and pine nuts) have been singled out in terms of reduced overall mortality associated with frequent weekly consumption. PREDIMED (‘PREvención con DIeta MEDiterránea’) is a large, robust and long-running nutrition trial based in Spain. For this study, the investigators randomised and evaluated 7,216 men and women aged 55 to 80 years (mean age 67) who were already participating in PREDIMED into 1 of 3 interventions: Mediterranean diets supplemented with 1) nuts, or 2) olive oil, or 3) a control low fat diet).¹

During a median follow-up of 4.8 years using food questionnaires, they looked at primary prevention of cardiovascular disease (CVD) ,cancer and overall mortality in each group. What they found was that nut consumption was associated with a significantly reduced risk of all-cause mortality and with risks of dying from CVD and cancer. Compared to non-consumers, participants consuming nuts more than three times per week (a serving was 28 g or 1 oz), which was about 32 per cent of the cohort had a 39 per cent lower mortality risk.

The Mediterranean diet + nuts group who consumed nuts more than three servings/week had the lowest total mortality risk. They also found that frequent nut eaters had healthier lifestyles: “Subjects who ate nuts more frequently had lower BMI and waist circumference, were less likely to smoke, and were more physically active compared to those who rarely or never consumed nuts.” This was epidemiology not a clinical intervention, so it cannot demonstrate cause and effect. But it found a strong association of frequent nut consumption amongst those people following a Mediterranean diet and reduced risks of cardiovascular disease and cancer. For those who were nut consumers already and who were in the intervention that supplemented the Mediterranean diet with more nuts, the news was even better: “more nuts at baseline and allocated to intervention with a MedDiet supplemented with nuts showed a significantly reduced total mortality risk of 63 per cent.”

Nuts are, of course, part of the Mediterranean diet, so this intervention supplemented that healthy eating pattern with additional nuts. This increased consumption of unsaturated fats, fibre, minerals such as magnesium, potassium, vitamins such as folate and tocopherols (vit E) and other bioactive compounds like phytosterols and polyphenols.

Taking the three arms of the study and thinking about the longer term effect, I think the big new message from this PREDIMED study is “it’s the nuts that make the difference in the longer term, not the olive oil”. The consumer message to take from this is that Mediterranean-type diets plus nuts work in the long term to reduce overall mortality, particularly from heart disease and to some extent from cancer. The exact reasons are yet to be untangled, but the overall message is clear. The authors of the commentary are strongly in favour of more consumer promotion to get over the message of healthy substitutions of nuts for other foods to make these simple changes.

It must be stressed that this study is not about adding nuts to poor diets and making no other changes. Nuts are not a magic bullet. Writing in the same journal, editorialists Rohrmann and Faeh at Zurich University, commenting on the PREDIMED research, concluded that we know that nuts are beneficial and it is now a question of how people can put this knowledge into everyday practice.² For this we need “to focus on the question of how to better promote nut consumption in the population and sustainably integrate it into the daily diet. Currently, several dietary guidelines recommend replacing one of five servings of fruits and vegetables a day by a serving of nuts. This appears to be a simple and practical recommendation to start with.”

There is a great deal that the peanut industry can do to promote the benefits of healthful eating which includes frequent consumption of peanuts; the best part is you don’t have to live in Spain to do it.

Source: American Peanut Council

¹ Guasch-Ferré M e al. “Frequency of nut consumption and mortality risk in the PREDIMED nutrition intervention trial”. BMC Medicine, 2013;11:164 DOI:10.1186/1741-7015-11-164

² Rohrmann S and Faeh D. “Should we go nuts about nuts?” BMC Medicine, 2013;11:165 DOI: 10.1186/1741-7015-11-165