3/11/15

TAKE-HOME MESSAGE

• Researchers evaluated Americans of African and European descent and Chinese individuals to determine the association of nut consumption with mortality. Increased nut consumption was significantly associated with reduced total mortality and specifically cardiovascular disease mortality among all ethnic groups.
• Researchers suggest that nuts may be a cost-effective option to reduce cardiovascular risk.

Primary Care
Written by David Rakel MD, FAAFP
Nuts and peanuts reduce mortality in everyone!

There has been high-quality research showing the health benefits of nuts.1,2 However, previous studies mainly looked at people of European descent of high socioeconomic standing. The authors of this study wanted to see if these mortality benefits would hold true in those of more diverse ethnicity with lower socioeconomic status.

Studies in three large populations from the southeastern United States and Shanghai, China, found similar benefits. Nut/peanut consumption was associated with a reduced risk for total and cardiovascular mortality. All-cause reduction was similar to the findings in the PREDIMED and NHS/NPFS studies showing that, compared with the lowest nut intake group, those eating the most had approximately a 20% reduction in mortality.

This study included specific assessment about peanuts, which are legumes, not true nuts. However, both share similar health benefits, and peanuts are more affordable—a 16-oz container of unsalted peanuts can be purchased for just $2.98. Remember to recommend a “handful, not a canful” since nuts and peanuts are high in calories.

References

• Bao Y, Han J, Hu FB, et al. Association of nut consumption with total and cause-specific mortality. N Engl J Med. 2013;369(21):2001-2011. http://www.nejm.org/doi/full/10.1056/NEJMoa1307352
• Estruch R, Ros E, Salas-Salvado J, et al. Primary prevention of cardiovascular disease with a Mediterranean diet. N Engl J Med. 2013;369(7):676-677. http://www.nejm.org/doi/full/10.1056/NEJMoa1200303

Abstract

IMPORTANCE

High intake of nuts has been linked to a reduced risk of mortality. Previous studies, however, were primarily conducted among people of European descent, particularly those of high socioeconomic status.

OBJECTIVE

To examine the association of nut consumption with total and cause-specific mortality in Americans of African and European descent who were predominantly of low socioeconomic status (SES) and in Chinese individuals in Shanghai, China.

DESIGN, SETTING, AND PARTICIPANTS

Three large cohorts were evaluated in the study. One included 71 764 US residents of African and European descent, primarily of low SES, who were participants in the Southern Community Cohort Study (SCCS) in the southeastern United States (March 2002 to September 2009), and the other 2 cohorts included 134 265 participants in the Shanghai Women’s Health Study (SWHS) (December 1996 to May 2000) and the Shanghai Men’s Health Study (SMHS) (January 2002 to September 2006) in Shanghai, China. Self-reported nut consumption in the SCCS (approximately 50% were peanuts) and peanut-only consumption in the SMHS/SWHS were assessed using validated food frequency questionnaires.

MAIN OUTCOMES AND MEASURES

Deaths were ascertained through linkage with the National Death Index and Social Security Administration mortality files in the SCCS and annual linkage with the Shanghai Vital Statistics Registry and by biennial home visits in the SWHS/SMHS. Cox proportional hazards regression models were used to calculate hazard ratios (HRs) and 95% CIs.

RESULTS

With a median follow-up of 5.4 years in the SCCS, 6.5 years in the SMHS, and 12.2 years in the SWHS, 14 440 deaths were identified. More than half of the women in the SCCS were ever smokers compared with only 2.8% in the SWHS. The ever-smoking rate for men was 77.1% in the SCCS and 69.6% in the SMHS. Nut intake was inversely associated with risk of total mortality in all 3 cohorts (all P < .001 for trend), with adjusted HRs associated with the highest vs lowest quintiles of intake being 0.79 (95% CI, 0.73-0.86) and 0.83 (95% CI, 0.77-0.88), respectively, for the US and Shanghai cohorts. This inverse association was predominantly driven by cardiovascular disease mortality (P < .05 for trend in the US cohort; P < .001 for trend in the Shanghai cohorts). When specific types of cardiovascular disease were examined, a significant inverse association was consistently seen for ischemic heart disease in all ethnic groups (HR, 0.62; 95% CI, 0.45-0.85 in blacks; HR, 0.60; 95% CI, 0.39-0.92 in whites; and HR, 0.70; 95% CI, 0.54-0.89 in Asians for the highest vs lowest quintile of nut intake). The associations for ischemic stroke (HR, 0.77; 95% CI, 0.60-1.00 for the highest vs lowest quintile of nut intake) and hemorrhagic stroke (HR, 0.77; 95% CI, 0.60-0.99 for the highest vs lowest quintile of nut intake) were significant only in Asians. The nut-mortality association was similar for men and women and for blacks, whites, and Asians and was not modified by the presence of metabolic conditions at study enrollment.

CONCLUSIONS AND RELEVANCE

Nut consumption was associated with decreased overall and cardiovascular disease mortality across different ethnic groups and among individuals from low SES groups. Consumption of nuts, particularly peanuts given their general affordability, may be considered a cost-effective measure to improve cardiovascular health.

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Journal Referencehttps://dl.dropboxusercontent.com/u/1546229/Logos%20and%20Images/JAMA_Internal_Medicine.png