walnut consumption and cardiovascular risk

Last edited 10/2021 and last reviewed 01/2022

Walnut consumption and cardiovascular risk

There is evidence that (1,2):

• more frequent consumption of nuts has been associated with lower CVD (cardiovascular disease)
• findings of small randomized controlled trials suggested cholesterol-lowering effects of nuts

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

Study results (3):

• 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)

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 study authors concluded that:

• "..On the basis of associations ascertained in cohort studies, the observed shift of the lipoprotein subclass phenotype suggests a reduction of lipoprotein-related CVD risk by long-term consumption of walnuts, which provides novel mechanistic insight for their potential cardiovascular benefit beyond effects on the standard lipid panel...."

Reference:

• Becerra-Tomas N et al. 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
• Sabate 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
• Rajaram S et al. Effects of Walnut Consumption for 2 Years on Lipoprotein Subclasses Among Healthy Elders – Findings from the WAHA Randomized Controlled trial Circulation 2021;144:00-00. DOI:10.1161/CIRCULATIONAHA.121.054051