Effects of Walnut Consumption as Part of a Low-Fat, Low-Cholesterol Diet on Serum Cardiovascular Risk Factors

Abstract

Serum components, such as lipoproteins, coagulation factors (factor VII, tissue plasminogen activator (tPA), plasminogen activator inhibitor-1 (PAI-1), fibrinogen), and homocysteine have been associated with cardiovascular disease. Dietary intervention with a low-fat, low-cholesterol diet has favorably influenced cardiovascular disease and certain food, specifically the consumption of nuts, has been associated with reduced cardiovascular risks. The effects of walnuts, as part of a low-fat, low-cholesterol diet, on serum cardiovascular risk factors were determined. Sixty-seven (67) outpatients with borderline high total cholesterol following a low-fat, low-cholesterol diet for six weeks before being randomly assigned to continue the diet or have 64 grams/day of walnuts in conjunction with the diet. After six weeks, the patients' diets were switched. Therefore, all patients consumed 64 grams/day of walnuts for six weeks during part of the trial as part of a low-fat, low cholesterol diet. Serum lipids demonstrated a significant reduction in triacyglycerols and favorable trend with decreases in total cholesterol, low-density lipoprotein (LDL) cholesterol, and a slight increase in high-density lipoprotein (HDL) cholesterol. No statistical effects on homocysteine or the coagulation factors were observed. However, there was a slight favorable trend for tPA and PAI-1. This study demonstrated that walnuts, when consumed as part of a low fat, low-cholesterol diet, have a beneficial effect on serum cardiovascular risk factors. However, these changes may not explain all of the beneficial effects that walnut consumption has on cardiovascular disease.

Dietary intake and coronary heart disease: A variety of nutrients and phytochemicals are important

“…As noted earlier, walnuts are a good source of ␣-linolenic acid, which is converted by the body to docosahexaenoic acid. A recent, randomized, crossover study found that individuals provided 643 g/d of walnuts for 6 weeks showed significant reduction in triacylglycerols and decreases in LDL with a slight increase in HDL cholesterol [19], confirming results demonstrated by an earlier, similar trial [20].…”

Nut consumption, body weight and insulin resistance

“…More striking is the fact that some studies found that when nuts are added to the diet, there is no associated increase in body weight even when total energy intake is substantially greater (Morgan & Clayshulte, 2000;Morgan et al, 2002). For example, adding 48 g of walnuts to the diet for 6 weeks did not increase weight although energy intake increased by 1661 kJ/day (Almario et al, 2001).…”

Long-term walnut supplementation without dietary advice induces favorable serum lipid changes in free-living individuals

“…Walnuts have a high fat content, as do other nuts, but are low in saturated fatty acids. Walnuts have consistently reduced serum cholesterol and improved the lipoprotein profile in several well-controlled short-term clinical trails (Sabaté et al, 1993;Almario et al, 2001;Iwamoto et al, 2002;Morgan et al, 2002;Zibaeenezhad et al, 2005) and recently reviewed by Banel and Hu (2009). The Food and Drug Administration issued a qualified health claim that says, 'Supportive but not conclusive research shows that eating 1.5 ounces per day of walnuts, as part of a low saturated fat and low cholesterol diet may reduce the risk of coronary heart disease' (Food and Drug Administration, 2003).…”