Long-term consumption of walnuts lowers LDL-c in healthy elderly
Levels of LDL-c, total cholesterol and IDL-c were lowered in participants on a walnut-supplemented diet compared to those on a walnut-free diet, in the WAHA study which enrolled healthy older individuals.
Effects of Walnut Consumption for 2 Years on Lipoprotein Subclasses Among Healthy Elders – Findings from the WAHA Randomized Controlled trialLiterature - Rajaram S, Cofán M, Sala-Vila A, et al., - Circulation 2021;144:00–00. DOI:10.1161/CIRCULATIONAHA.121.054051
Introduction and methods
More frequent consumption of nuts has been associated with lower CVD and findings of small randomized controlled trials suggested cholesterol-lowering effects of nuts [1,2]. However, these studies were limited; there was no focus on elderly individuals, no recruitment from diverse geographical areas, had no duration >2 years, and no information on effects on lipoprotein subclasses.
Therefore, the WAHA study (Walnuts and Healthy Aging) [3] was conducted; a 2-center (Spain and California, USA), 2-year, parallel-group randomized controlled trial in which the effects of walnut-supplemented diet were examined in healthy elderly individuals. Changes in lipoproteins were prespecified secondary outcomes. Cognitive healthy elders (63-79 years) without major comorbidities were included. Participants (n=628) were randomized to a walnut-free or walnut-supplemented diet (approximately 15% of energy, 30-60 g/d). Compliance with the diet was good with a stable body weight in both groups.
Main results
- Compared to the walnut-free group, participants in the walnut group had decreased (mg/dL) total cholesterol (mean -8.5 [95%CI: -11.2 to -5.4]), LDL-c (mean -4.3 [95%CI: -6.6 to -1.6]) and intermediate-density lipoprotein cholesterol (mean -1.3 [95%CI: -1.5 to -1.0]), corresponding to 4.4%, 3.6% and 16.8% reductions., respectively.
- Levels of triglycerides and high-density lipoprotein cholesterol were unchanged.
- Total LDL particles and small LDL particle number were decreased in the walnut group by 4.3% and 6.1%, respectively.
- LDL-c reduction by walnut diet was more pronounced in men than in women (7.9% in men vs. 2.6% in women, P-interaction=0.007).
Conclusion
In the WAHA study, incorporation of walnuts to a diet in elderly individuals resulted in modest reductions of LDL-c, total cholesterol and IDL-c compared to a walnut-free diet.
The authors write: ‘Our data reinforce the notion that regular walnut consumption may be a useful part of a multicomponent dietary intervention or dietary pattern to lower atherogenic lipids and improve CVD risk’.
References
1. Becerra-Tomás N, Paz-Graniel I, Kendall CWC, Kahleova H, Rahelić D, Sievenpiper JL, Salas-Salvadó J. Nut consumption and incidence of cardiovascular diseases and cardiovascular disease mortality: a meta-analysis of prospective cohort studies. Nutr Rev. 2019;77:691–709. doi: 10.1093/nutrit/nuz042
2. 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
3. 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, et al. 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