Do walnuts reduce cholesterol and serum lipid levels?

From: Annals of Internal Medicine

Journal rating:
rating: 99%
Study Quality:
rating: 85%

Overall Reliability

Article Quality:
rating: 10%
rating: 0%


  • 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)


Editors Notes

  • 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.