MedWire News: Results from a systematic review and meta-analysis show that consumption of a walnut-rich diet leads to significant improvements in total and low-density lipoprotein (LDL) cholesterol.
In this study the researchers found no significant affects on high-density lipoprotein (HDL) cholesterol, but there was a trend for decreased triglycerides with increased walnut consumption.
“Large prospective studies have consistently observed a reduction in cardiovascular disease risk and mortality associated with increased nut consumption,” say Dierdre Banel and Frank Hu from Harvard University in Cambridge, Massachusetts, USA in the American Journal of Clinical Nutrition.
Unlike many nuts which are high in monounsaturated fatty acids, walnuts have a high polyunsaturated fatty acid content and are thought to be particularly beneficial for cardiovascular health, as reported by Medwire News.
Banel and Hu carried out a meta-analysis of 13 studies including a total of 365 participants. Participants consumed diets with a high walnut content contributing 10–24% of total calories for a period of 4–24 weeks.
When compared with control diets, the researchers found that consumption of walnut supplemented diets led to significant reductions in total (10.30 mg/dl; 0.27 mmol/l) and LDL (9.20 mg/dl; 0.24 mmol/l) cholesterol.
No significant differences were observed for HDL cholesterol between the two diet groups. There was a mean 3.9 mg/dl (0.04 mmol/l) reduction in triglycerides observed for the walnut-supplemented versus the control diet group, but this was not statistically significant.
Of note, contrary to previous reports, no adverse effects on body weight linked to walnut consumption were recorded.
Banel and Hu conclude: “Although larger and longer-term trials are needed to address the effects of walnuts on cardiovascular risk and body weight, the evidence summarized in this review indicates that walnuts can be incorporated into one’s diet for the improvement of cardiovascular disease risk factors, namely lipid profiles.”
MedWire (www.medwire-news.md) is an independent clinical news service provided by Current Medicine Group, a part of Springer Science+Business Media. © Current Medicine Group Ltd; 2009
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