Study finds eating walnuts daily can help manage cholesterol in older adults

A new study published in the journal Circulation found an association between regular daily walnut consumption and sustained lower levels of cholesterol among 708 healthy older adults who included walnuts as part of their diet for four years.

Walnuts are a rich source of omega-3 ALA (alpha-linolenic acid), which research has shown to have a beneficial role in the prevention and reduction of heart disease[1] and which can contribute to the maintenance of normal blood cholesterol levels[2].

Three decades of research has shown walnuts can support cardiovascular health. While small, short-term randomized controlled trials (RCTs) have demonstrated that diets supplemented with nuts have a consistent cholesterol-lowering effect, there have been no trials of nut-enriched diets for lipid changes focused on elderly individuals and very little information focused on the effects of nuts on lipoproteins like low-density cholesterol (LDL); often called the “bad” cholesterol[3]. For the first time, the researchers went beyond LDL cholesterol and looked at all types of lipoproteins. One ½ cup serving of walnuts a day made a positive effect on lipoproteins.

In addition, there is a misconception that nuts might lead to weight gain because of the calorie content – in this study the subjects ate ½ cup of walnuts every day and did not gain weight. The findings reinforce the notion that regular walnut consumption may be a useful part of a heart-healthy eating pattern. Study co-author Emilio Ros, M.D., Ph.D., director of the Lipid Clinic at the Endocrinology and Nutrition Service of the Hospital Clínic of Barcelona in Spain commented; “Eating a handful of walnuts every day is a simple way to promote cardiovascular health. Many people are worried about unwanted weight gain when they include nuts in their diet”, “Our study found that the healthy fats in walnuts did not cause participants to gain weight”.

This study is part of The Walnuts and Healthy Aging (WAHA) study, a two-center (Barcelona, Spain and California, USA), 2-year, parallel-group RCT testing the effects of walnut-supplemented diets in healthy elders[4]. WAHA is the largest and longest nut trial to date, overcoming the limitations of prior smaller and shorter nut studies. WAHA is supported by a grant from the California Walnut Commission.

[1] https://efsa.onlinelibrary.wiley.com/doi/abs/10.2903/j.efsa.2009.1252

[2] EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA); Scientific Opinion on the substantiation of health claims related to walnuts and maintenance of normal blood LDL‐cholesterol concentrations (ID 1156, 1158) and improvement of endothelium‐dependent vasodilation (ID 1155, 1157) pursuant to Article 13(1) of Regulation (EC) No 1924/2006. EFSA Journal 2011; 9( 4):2074. [19 pp.]. doi:10.2903/j.efsa.2011.2074.

[3] Sabaté J, Oda K, Ros E. Nut consumption and blood lipid levels: a pooled analysis of 25 intervention trials. Arch Intern Med. 2010;170:821-827. doi:10.1001/archinternmed.2010.79.

[4] Sala-Vila A, Valls-Pedret C, Rajaram S, Coll-Padrós N, Cofán M, Serra-Mir M, Pérez-Heras AM, Roth I, Freitas-Simoes TM, Doménech M, Calvo C, López-Illamola A, Bitok E, Buxton NK, Huey L, Arechiga A, Oda K, Lee GJ, Corella D, Vaqué-Alcázar L, Sala-Llonch R, Bartrés-Faz D, Sabaté J, Ros E. Effect of a 2-year diet intervention with walnuts on cognitive decline. The Walnuts And Healthy Aging (WAHA) study: a randomized controlled trial. Am J Clin Nutr.2020;111:590-600. doi: 10.1093/ajcn/nqz328