Nut Consumption and Risk of Cardiovascular Disease

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.

Keywords: cardiovascular disease; coronary heart disease; nuts; peanuts; stroke; tree nuts.

Figure 1. Hazard Ratios for Cardiovascular Disease in Subgroups

Multivariable hazard ratios for pooled analysis of the three cohorts (Nurses’ Health Study I and II and Health Professionals Follow-up Study) for total cardiovascular disease among study participants who consumed nuts two or more times per week versus those who never consumed nuts were adjusted for updated covariates: age (continuous); Caucasian (yes/no); body-mass index (<23, 23–24.9, 25–29.9, 30–34.9, ≥35 kg/m2); physical activity (metabolic-equivalents/week, quintiles); smoking status (never, past, current 1–14 cigarettes/d, current 15–24 cigarettes/d, current ≥25 cigarettes/d); physical examination for screening purposes (yes/no); current multivitamin use(yes/no); and current aspirin use(yes/no); family history of diabetes mellitus (yes/no), myocardial infarction (yes/no), or cancer(yes/no); history of diabetes mellitus (yes/no), hypertension (yes/no), or hypercholesterolemia (yes/no); intake of total energy, alcohol, red or processed meat, fruits, and vegetables (quintiles); and, in women, menopausal status and hormone use (premenopausal, postmenopausal never users, postmenopausal past users, postmenopausal current users). In NHS II, the multivariable model was further adjusted for oral contraceptive (never, past and current users). Results were pooled with the use of the fixed-effects model. Horizontal lines represent 95% confidence intervals.

Central Illustration. Cardiovascular Disease, Coronary Heart Disease and Stroke Based on Frequency of Nut Consumption and Type of Nut: Hazard Ratios

Abbreviations: NHS, Nurses’ Health Study; NHS II, Nurses’ Health Study II; HPFS, Health Professionals Follow-up Study. Multivariable hazard ratios for total cardiovascular disease among study participants who consumed nuts two or more times per week (one or more times per week for walnuts) versus those who never or almost never consumed nuts, were adjusted for updated covariates: age (continuous); Caucasian (yes/no); body-mass index (<23, 23–24.9, 25–29.9, 30–34.9, ≥35 kg/m2); physical activity (metabolic-equivalents/week, quintiles); smoking status (never, past, current 1–14 cigarettes/d, current 15–24 cigarettes/d, current ≥25 cigarettes/d); physical examination for screening purposes (yes/no); current multivitamin use(yes/no); and current aspirin use(yes/no); family history of diabetes mellitus (yes/no), myocardial infarction (yes/no), or cancer(yes/no); history of diabetes mellitus (yes/no), hypertension (yes/no), or hypercholesterolemia (yes/no); intake of total energy, alcohol, red or processed meat, fruits, and vegetables (quintiles); and, in women, menopausal status and hormone use (premenopausal, postmenopausal never users, postmenopausal past users, postmenopausal current users). In NHS II, the multivariable model was further adjusted for oral contraceptive use (never, past and current users). Peanut butter models were additionally adjusted for glycemic load, soda, and white bread intake (quintiles). Results were pooled with the use of the fixed-effects model. Horizontal lines represent 95% confidence intervals.