Cholesterol lowering effects of nuts compared with a Canola oil enriched cereal of similar fat composition.
ABSTRACT 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.
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ABSTRACT: Ingestion of alpha linolenic acid (ALA), with the richest source among dry fruits such as walnuts, is associated with cardiovascular prevention. The aim of this study was to selectively evaluate the effects of moderate walnut consumption on the levels of ALA and its metabolic derivatives in human blood. After a 2-week run-in period, 10 volunteers consumed 4 walnuts per day (in addition to their habitual diet) for 3 weeks. Fatty acid profiles, with special attention to levels of ALA and long chain polyunsaturated fatty acids (LC-PUFA), were assessed in blood drops collected from fingertips. The data indicate that the administration of a few walnuts a day for 3 weeks significantly increases blood levels, not only of ALA (from 0.23+/-0.07 SD to 0.47+/-0.13 SD), but also of its longer chain derivative eicosapentaenoic acids (EPA) (from 0.23+/-0.37 to 0.82+/-0.41) with levels remaining elevated over basal values after washout. The findings of this pilot study indicate that plant ALA in appropriate food items favourably affects the n-3 LC-PUFA status.Nutrition, metabolism, and cardiovascular diseases: NMCD 08/2007; 17(6):457-61. DOI:10.1016/j.numecd.2006.02.004 · 3.88 Impact Factor
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ABSTRACT: Although several studies have assessed the effects of nut consumption (tree nuts, peanuts, and soy nuts) on blood pressure (BP), the results are conflicting. The aim was to conduct a systematic review and meta-analysis of published randomized controlled trials (RCTs) to estimate the effect of nut consumption on BP. The databases MEDLINE, SCOPUS, ISI Web of Science, and Google Scholar were searched for RCTs carried out between 1958 and October 2013 that reported the effect of consuming single or mixed nuts (including walnuts, almonds, pistachios, cashews, hazelnuts, macadamia nuts, pecans, peanuts, and soy nuts) on systolic BP (SBP) or diastolic BP (DBP) as primary or secondary outcomes in adult populations aged ≥18 y. Relevant articles were identified by screening the abstracts and titles and the full text. Studies that evaluated the effects for <2 wk or in which the control group ingested different healthy oils were excluded. Mean ± SD changes in SBP and DBP in each treatment group were recorded for meta-analysis. Twenty-one RCTs met the inclusion criteria. Our findings suggest that nut consumption leads to a significant reduction in SBP in participants without type 2 diabetes [mean difference (MD): -1.29; 95% CI: -2.35, -0.22; P = 0.02] but not in the total population. Subgroup analyses of different nut types suggest that pistachios, but not other nuts, significantly reduce SBP (MD: -1.82; 95% CI: -2.97, -0.67; P = 0.002). Our study suggests that pistachios (MD: -0.80; 95% CI: -1.43, -0.17; P = 0.01) and mixed nuts (MD: -1.19; 95% CI: -2.35, -0.03; P = 0.04) have a significant reducing effect on DBP. We found no significant changes in DBP after the consumption of other nuts. Total nut consumption lowered SBP in participants without type 2 diabetes. Pistachios seemed to have the strongest effect on reducing SBP and DBP. Mixed nuts also reduced DBP. © 2015 American Society for Nutrition.American Journal of Clinical Nutrition 03/2015; 101(5). DOI:10.3945/ajcn.114.091595 · 6.92 Impact Factor