December 04, 2017
Abstract
BACKGROUND
The associations between specific types of nuts, specifically peanuts and walnuts, and cardiovascular disease remain unclear.
OBJECTIVES
The authors sought to analyze the associations between the intake of total and specific types of nuts and cardiovascular disease, coronary heart disease, and stroke risk.
METHODS
The authors included 76,364 women from the Nurses’ Health Study (1980 to 2012), 92,946 women from the Nurses’ Health Study II (1991 to 2013), and 41,526 men from the Health Professionals Follow-Up Study (1986 to 2012) who were free of cancer, heart disease, and stroke at baseline. Nut consumption was assessed using food frequency questionnaires at baseline and was updated every 4 years.
RESULTS
During 5,063,439 person-years of follow-up, the authors documented 14,136 incident cardiovascular disease cases, including 8,390 coronary heart disease cases and 5,910 stroke cases. Total nut consumption was inversely associated with total cardiovascular disease and coronary heart disease after adjustment for cardiovascular risk factors. The pooled multivariable hazard ratios for cardiovascular disease and coronary heart disease among participants who consumed 1 serving of nuts (28 g) 5 or more times per week, compared with the reference category (never or almost never), were 0.86 (95% confidence interval: 0.79 to 0.93; p for trend = 0.0002) and 0.80 (95% confidence interval: 0.72 to 0.89; p for trend <0.001), respectively. Consumption of peanuts and tree nuts (2 or more times/week) and walnuts (1 or more times/week) was associated with a 13% to 19% lower risk of total cardiovascular disease and 15% to 23% lower risk of coronary heart disease.
CONCLUSIONS
In 3 large prospective cohort studies, higher consumption of total and specific types of nuts was inversely associated with total cardiovascular disease and coronary heart disease.
Written by David Rakel MD, FAAFP
Nuts Matter
Before the scientific method was born, people had to guess which plants benefit health. One tool that was used was the “Doctrine of Signatures.” This proposed that, if a plant looked like an organ, it must be good for that organ. Unfortunately, science has not shown this to be valid. But the coincidence of these “look-alikes” may help us remember some of our science.
The evidence for the benefits of nuts continues to grow. The PREDIMED study showed that 4 oz of nuts (about a handful) daily was associated with a 20% reduction in all-cause mortality and a 28% reduction in the incidence of major cardiovascular events.1,2
This study looked at three large cohorts (Nurses’ Health Study, Nurses’ Health Study II, and the Health Professionals Follow-Up Study) from 1986 to 2012 and found similar results. Participants in those studies who ate 1 oz of nuts five or more times a week compared with those who did not eat nuts had a 20% lower risk of cardiovascular disease and a 14% lower risk of cerebrovascular disease.
What does this study add?
These investigators have singled out walnuts and peanut butter. There was no benefit from eating peanut butter but there was from eating peanuts. Consuming walnuts one or more times a week was associated with a 21% lower risk of cardiovascular disease and a 17% lower risk of stroke. Walnuts differ from other nuts in that they have more tocopherols (vitamin E).
The authors of this paper remind us that, despite nuts being rich in calories, there is no evidence supporting weight gain with moderate consumption. To the contrary, eating nuts is associated with weight loss possibly due to the fact that they make people feel full, reducing the intake of unhealthy snacks.
Despite the fact that the “Doctrine of Signatures” has no scientific validity, it does help us remember the science. Walnuts look like a brain and are good for the brain. Most nuts kind of look like a heart, and they are good for the heart.
References