MedWire News: Long-term dietary supplementation with walnuts significantly reduces total cholesterol and triglycerides in individuals with normal to moderately high total cholesterol, show study results.
The researchers also found that low-density lipoprotein (LDL) cholesterol was reduced in these individuals over a 6-month period, but the reduction was only of borderline significance.
Walnut consumption has been shown to significantly reduce serum lipids in short-term studies, as reported by MedWire News. However, there is less information on the effect and sustainability of more long-term consumption, say researchers.
In this study, Setareh Torabian (California State University, Northridge, USA) and colleagues evaluated the effects of a walnut-supplemented versus a habitual diet on serum lipids in 87 individuals aged 54 years on average with normal to moderately high total cholesterol levels.
At baseline half the participants were assigned a walnut-supplemented diet (12% of total daily energy intake; 28–64 g/day) and half continued to eat their habitual diet (controls) for a period of 6 months. At the 6-month point the participants switched to the alternative diet for another 6 months.
Measurements were taken from the participants at clinic visits carried out at 2-monthly intervals. The team found that after adjusting for confounders total cholesterol and triglycerides were significantly reduced at study completion by 0.18 and 0.16 mmol/l (6.96 and 14.17 mg/dl), respectively, in the walnut-supplemented group compared with controls.
LDL cholesterol was also reduced by 0.16 mmol/l (6.19 mg/dl) in this group, but this was only of borderline significance.
The beneficial effects of walnut consumption seen in this study were most significant in the participants with the highest levels of total cholesterol at baseline, says the team.
Of note, no significant change was observed in high-density lipoprotein (HDL) cholesterol levels or in the LDL-to-HDL cholesterol ratio.
“The lipid-lowering effects of walnuts that we found in our study were consistent with previous reports, and with a recent meta-analysis, showing that a walnut diet decreases total cholesterol levels,” observe Torabian et al.
They conclude: “The take-home message is that walnuts work to lower your cholesterol in the long term.”
The results of this study are published in the European Journal of Clinical Nutrition.
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