Do walnuts reduce cholesterol and serum lipid levels?
From: Annals of Internal Medicine
- Zambón, D., Sabaté, J., Muñoz, S., Campero, B., Casals, E., Merlos, M., Laguna, J.C., Ros, E., 2000. Substituting walnuts for monounsaturated fat improves the serum lipid profile of hypercholesterolemic men and women. A randomized crossover trial. Ann. Intern. Med. 132, 538–546.
- 55 men and women with polygenic hypercholesterolemia
- A cholesterol-lowering Mediterranean diet and a diet of similar energy and fat content in which walnuts replaced approximately 35% of the energy obtained from monounsaturated fat.
- Patients followed each diet for 6 weeks.
- Compared with the Mediterranean diet, the walnut diet produced an average reduction of 4.1% in total cholesterol level, 5.9% in LDL cholesterol level, and 6.2% in lipoprotein level.
- The average reduction in the changes in serum lipid levels were 0.28 mmol/L, 10.8 mg/dL for total cholesterol level, 11.2 mg/dL for LDL cholesterol level, and 0.021 g/L for lipoprotein level.
- Lipid changes were similar in men and women except for lipoprotein levels, which decreased only in men.
- The authors concluded that regular intake of walnuts has a cholesterol-lowering effect.
- Yes (with confidence)
- Walnuts are particularly rich in polyunsaturated fatty acids, and evidence suggests that frequent walnut consumption protects against coronary heart disease
- The study was small, of short-duration, and the participants were on a mediterranean diet which may itself have accounted for the results.