A review and analysis published recently in the American Journal of Clinical Nutrition suggested that eating walnuts could improve blood lipid levels (cholesterol and triglycerides) without causing weight gain or increasing blood pressure.
The authors looked at twenty-six controlled trials evaluating the effects of walnut consumption on blood lipids and other cardiovascular risk factors. Together, the studies involved over 1,000 people. Those who ate more walnuts had a 3.3 percent greater reduction in total blood cholesterol, a 3.7 percent greater reduction in LDL cholesterol, and a 5.5 percent greater reduction in triglyceride concentrations compared with those you did not eat walnuts. For people who originally followed an American- or Western-style diet, improvement in blood lipid levels following the addition of walnuts was even greater. Weight and blood pressure in the walnut-enriched-diet groups were not significantly different from those of the controls.
Frequent nut consumption is associated with lower risk of cardiovascular disease in numerous studies. Nuts are a good source of health-promoting nutrients, and walnuts are especially rich in alpha-linolenic acid, which is a precursor to the heart-healthy omega-3 fatty acids found in fish oils. It is important to remember that just adding nuts to an otherwise poor diet is unlikely to result in the desired effect. But choosing walnuts and other nuts in place of foods high in refined carbohydrate can improve diet quality, and perhaps health.