The Effect of Walnuts on Serum Lipids Consumed as Part of the National Cholesterol Educational Panel Step I DIET

• Published in: Journal of the American Dietetic Association 1999-09, Vol.99 (9), p.A109-A109
• Main Authors: Horton, K.L., Morgan, J.M., Uhrin, L.E., Boyle, M.R., Altomare, P., Laskowsky, C., Walker, K.E., Stanton, M.M., Newman, L.M., Capuzzi, D.M.
• Format: Article
• Language: English
• ISSN: 0002-8223; 1878-3570
• DOI: 10.1016/S0002-8223(99)00786-5

Using appropriate dietary modification, many studies have shown a beneficial impact of serum cholesterol lowering on the risk of coronary heart disease (CHD). In addition, an association between certain types of food, specifically the consumption of nuts, has been associated with reduced cardiovascular risks. Two small studies carried out in volunteers in a controlled environment provided suggestive evidence for a cholesterol lowering effect attributable to walnut ingestion. The purpose of this study was to determine whether the consumption of walnuts by hypercholesterolemic, free living men and women had a favorable effect on their serum lipid levels [total cholesterol (TC), HDL cholesterol (HDL-C), LDL cholesterol (LDL-C), triglycerides (TG)] when consumed as part of a NCEP Step I diet. A total of 67 subjects with total cholesterol levels >200 mg/dl enrolled in an open-label, randomized, crossover design trial. Subjects received diet instruction by a registered dietitian on the NCEP Step I diet and maintained 3-day diet records between visits. Subjects completed a 6-week dietary lead-in period during which lipid response to this diet was established. Subjects were then randomly assigned to one of two treatment groups for a 6 week period: continuation of Step I diet (reference diet group) or to a diet group wherein subjects consumed 2.25 ounces/day of walnuts as part of the NCEP Step I diet (the Walnut diet). After 6 weeks, all patients were switched to the alternate diet for an additional 6-week period. Results of the study showed that TC, LDL-C, and TG levels remained stable when subjects were randomized to the reference diet. However, while consuming the Walnut diet, subjects demonstrated a reduction in TC by 3%, LDL-C by 4% and TG by 12%. These changes in lipid levels demonstrated a beneficial trend of the Walnut diet (p= 0.10, NS) and no adverse changes in serum lipoprotein regulation. The results suggest that consumption of walnuts favorably affect serum lipid levels, and can be used as a flavorflil snack while adhering to the NCEP Step I diet.