Cardiovascular disease (CVD) is an important public health issue. According to the World Health Organization (WHO), it is the leading cause of death worldwide, affecting approximately 17.7 million people in 2015. Importantly, CVDs are susceptible to behavior modifications. In this sense, a healthy diet is one of the lifestyle components that could be promoted to help address this global health concern.
Different dietary patterns, such as the Mediterranean dieta, the DASH diet, despite their high fat content (mainly unsaturated fatty acids), are also rich in minerals, vitamins, fiber, and bioactive compounds. Given this exceptional nutritional profile, frequent nut consumption has been inversely associated with a lower risk of CVD in large prospective cohort studies, which have been summarized in several meta-analyses.
A 2-year study showed that participants who consumed about half a cup of walnuts each day had lower levels of low-density lipoprotein (LDL) cholesterol compared with their levels at the beginning of the study. These individuals also experienced a reduction in total cholesterol.
The group of researchers did an evaluation of multiple studies and found that these studies showed a significant inverse association between total nut consumption and the risk of CVD incidence and mortality, coronary heart disease (CHD) incidence and mortality and atrial fibrillation.
Regarding specific types of nuts, tree nut consumption was associated with lower risk of CVD and CHD incidence, while peanut consumption was associated with a lower incidence and mortality from CVD, stroke and CHD, and walnut consumption with a lower incidence of CVD, stroke and CHD.
One study evaluated by the researchers found that individuals with diabetes had similar results, with individuals consuming ≥5 servings of total nuts per week presented a lower risk of CVD incidence, CHD incidence and CVD mortality than those consuming less than 1 serving per month.
A study from the Lipid Clinic at the Endocrinology and Nutrition Service of the Hospital Clinic of Barcelona in Spain reported that walnuts can lower cholesterol, improve endothelial function, reduce blood pressure and have anti-inflammatory effects. The senior author of the study Dr. Emilio Ros, said to Medical News Today in an interview that this is because walnuts have an optimal composition of nutrients and bioactives, including sizable amounts of alpha-linolenic acid, the vegetable omega-3 fatty acid, the highest polyphenol content of all nuts and phytomelatonin.
Dr. Ros also indicated that regularly eating walnuts will lower your LDL cholesterol and improve the quality of LDL particles, rendering them less atherogenic (less prone to enter the arterial wall and build up atherosclerosis, the basis of cardiovascular diseases), and this will occur without unwanted weight gain in spite of the high fat (healthy vegetable fat, though) content of walnuts. The researchers emphasized the importance of eating just a handful per day of nuts and walnuts and not a larger amount.
Becerra-Tomás N, Paz-Graniel I, W C Kendall C, et al. Nut consumption and incidence of cardiovascular diseases and cardiovascular disease mortality: a meta-analysis of prospective cohort studies. Nutr Rev. 2019;77(10):691-709. doi:10.1093/nutrit/nuz042.