Fatty acid composition of nuts – implications for cardiovascular health

Abstract

It is well established that, due to their high content of saturated fatty acids (SFA), the intake of meat and meat products is strongly associated with elevated blood cholesterol concentrations and an increased risk of hypertension, diabetes and cardiovascular diseases. Conversely, the intake of foods rich in unsaturated fatty acids, such as those contained in most vegetable fats and oils and oily fish, is associated with improved lipid profiles, a lower potency of intermediate biomarkers of atherosclerosis and lesser incidence of cardiovascular diseases. There are persuasive evidences that dietary substitution of monounsaturated fatty acids (MUFA) or n-6 polyunsaturated fatty acids (PUFA) for SFA lowers blood cholesterol and may have beneficial effects on inflammation, thrombosis, and vascular reactivity. MUFA may have an advantage over PUFA because enrichment of lipoprotein lipids with MUFA increases their resistance to oxidation. Marine n-3 PUFA have a number of anti-atherosclerotic effects, including anti-arrhythmic properties and, at relatively high doses, reduce serum triglycerides. These effects appear to be shared in part by vegetable n-3 PUFA. Nuts are natural foods rich in unsaturated fatty acids; most nuts contain substantial amounts of MUFA, while walnuts are especially rich in both n-6 and n-3 PUFA. Healthy fats in nuts contribute to the beneficial effects of frequent nut intake observed in epidemiological studies (prevention of coronary heart disease, diabetes, and sudden death) and in short-term feeding trials (cholesterol lowering, LDL resistance to oxidation, and improved endothelial function).

Frequency of nut consumption and mortality risk in the PREDIMED nutrition intervention trial

“…Results are expressed as hazard ratios (HRs) with 95% confidence intervals (CIs). Given the different nutritional composition of walnuts and other nuts [1], we performed separate analyses for the frequency of total nut consumption, walnut consumption, and consumption of nuts excluding walnuts. After the unadjusted model, another model was adjusted for age (continuous), sex and intervention group.…”

“…Nuts are an important component of the so-called Mediterranean diet (MedDiet) and a good source of unsaturated fatty acids, fiber, minerals (potassium, calcium and magnesium), vitamins (folate and tocopherols) and other bioactive compounds, such as phytosterols and polyphenols [1]–[4]. …”

Health Benefits of Nut Consumption

“…Thus, nuts are one of the natural plant foods richest in fat after vegetable oils. However, the fatty acid composition of nuts is beneficial because the saturated fatty acid (SFA) content is low (4-16%) and nearly half of the total fat content is made up of unsaturated fat, monounsaturated fatty acids MUFA (oleic acid) in most nuts, similar proportions of MUFA and polyunsaturated fatty acids (PUFA), mostly linoleic acid, in Brazil nuts, a predominance of PUFA over MUFA in pine nuts, and mostly PUFA, both linoleic acid and α-linolenic acid (ALA), the plant omega-3 fatty acid, in walnuts [6]. With regard to walnuts, it must be underlined that they are a whole food with the highest content in ALA of all edible plants [28].…”

“…The consumer definition also includes peanuts ( Arachis hypogea ), which botanically are groundnuts or legumes but are widely identified as part of the nuts food group. In addition, peanuts have a similar nutrient profile to tree nuts [5,6]. Although chestnuts ( Castanea sativa ) are tree nuts as well, they are different from all other common nuts because of being starchier and having a different nutrient profile.…”

“…The mechanism for these salutary effects probably lies in the synergistic interaction of the many bioactive constituents of nuts, which may all favorably influence human physiology. Thus, nuts contain high amounts of vegetable protein [5] and fat, mostly unsaturated fatty acids [6]. They are also dense in a variety of other nutrients and provide dietary fiber [23], vitamins (e.g., folic acid, niacin, tocopherols, and vitamin B6), minerals (e.g., calcium, magnesium, potassium) and many other bioactive constituents such as phytosterols [24] and phenolic compounds [25].…”