An increase in nut consumption is associated with lower risk of chronic disease and mortality.
Heart disease and cancer caused 25.5 million deaths worldwide in 2013, making them two of the most common causes of death. Studies show that eating more nuts may reduce risk of cardiovascular disease and cancer. Nuts are high in fiber, healthy fats, vitamin E, and antioxidants, all of which may improve cardiovascular health. Nuts also contain other bioactive compounds that may slow cell proliferation, thereby reducing cancer risk. However, the relationship between nuts and the risk of other causes of death is not as well known.
A study published in BMC Medicine by Aune et al. reviewed twenty studies of nut intake and incidence of mortality from heart disease, stroke, diabetes, and respiratory, neurodegenerative, kidney or infectious disease. Out of 48,380 records identified by PubMed and EMBASE databases (from as early as 1947 through July 2016), these twenty studies were prospective studies of nut intake and mortality that included relative risk (RR) estimates and 95% confidence intervals (CI). Investigators compiled all the data from the 20 studies and calculated summary RRs and 95% CIs of cardiovascular disease, total cancer, and all-cause and cause-specific mortality. They also calculated dose-response curves to assess whether the quantity of nuts eaten affected mortality risks. Because the data came from many different studies, the authors attempted to account for between-study variation and small study effects by calculating heterogeneity and bias statistics (Q and I2).
Overall, dose-response analyses included 12,331 coronary heart disease cases, 9,272 stroke cases, 18,655 cardiovascular disease cases, 18,490 cancer cases, and 85,870 deaths out of almost 820,000 participants. The study found that eating one serving of nuts per day (1 serving = 28 grams) was associated with a 24% reduction in relative risk for heart disease. Relative risk of stroke and total cancer were reduced by 11% and 18%, respectively. Risks for both cardiovascular disease and all-cause mortality were each reduced by 19%. A one serving per day increase in nut consumption also reduced relative risk of mortality from respiratory disease, diabetes, and infectious disease, with 52%, 39%, and 75% risk reductions, respectively. The authors estimated that approximately 4.4 million premature deaths may be associated with eating less than 20 grams of nuts per day.
In summary, nuts are great sources of unsaturated fats, protein, fiber, vitamin E, potassium, magnesium, and phytochemicals. These data support the idea that eating at least 20 grams of nuts per day may reduce the risk of many common causes of mortality.
Written By: Cindi A. Hoover, Ph.D.