Cholesterol lowering effects of nuts compared with a Canola oil enriched cereal of similar fat composition

Small quantities of nuts protect against subsequent cardiovascular risk. There is speculation that the cholesterol lowering effect associated with nut consumption arises primarily from the fatty acid composition of nuts but may be caused by some other component. To evaluate this possibility we compared the effect of various nuts, against a Canola oil based cereal with a comparable fatty acid profile, on lipids, lipoproteins and fatty acids to determine whether the fatty acid profile of nuts explains their cholesterol lowering effects.

Twenty-eight men and women with mean (s.d.) levels of total and low density lipoprotein cholesterol of 6.0 (1.1) mmol/L, and 4.1 (1.0) mmol/L, respectively and a mean body mass index (BMI) of 26.9 (3.2) kg/m2 took part in a randomised cross over trial. For two periods of six weeks, separated by a four-week washout, participants were asked to consume a low saturated fat diet, which included either 30 g/d nuts (nut diet) or one serving of a cereal containing Canola oil (cereal diet). There were no significant differences in the lipids, lipoproteins, plasma fatty acids or other variables between the two diets at the end of the study. Total cholesterol (TC) and low density lipoprotein cholesterol (LDL-C) were lower on both experimental diets than at baseline, 0.51 mmol/L and 0.40 mmol/L (p<0.001, p<0.01), respectively on the nut diet and 0.42 mmol/L and 0.37 mmol/L (p<0.001, p<0.01), respectively on the cereal diet.

A 30 g serving of nuts, or a serving of a Canola oil enriched cereal with a similar fatty acid composition reduced total and LDL cholesterol to a similar extent when consumed as part of a lipid lowering diet. Results suggest that foods with a similar fatty acid composition to nuts can produce comparable decreases in lipoprotein mediated cardiovascular risk.