Insights & Discussion
Walnut consumption coupled with concurrent training improves lipid profile, steroid hormone levels, and systematic inflammation in elderly men.
The study created two matched groups of fit elderly men and placed one on a diet inclusive of walnuts (15g/day for six weeks) alongside their concurrent (resistance and endurance) training. The other group did the concurrent training without the walnut-supplemented diet. The study then took fasting blood samples from the participants 48 hours before and after the intervention for biochemical assessments.
The group consuming walnuts saw a significant improvement in their lipid profiles with increased high-density lipoprotein levels and decreased total cholesterol, low-density lipoprotein and triglyceride levels. The walnut-eating participants also saw an increase in testosterone levels after the training, which was significantly higher than the group not consuming walnuts. Additionally, the walnut-consuming group experienced lowered cortisol levels and decreased C-reactive protein compared to the group not consuming walnuts. It is plausible the results could be attributed to the presence of polyunsaturated fatty acids in walnuts.
Discover Related Insights
Tiger nut and walnut supplementation in diets can improve testosterone levels and help control vasoconstriction, potentially benefiting hypertensive individuals.
2021 Nutrients Cyperus esculentus L. and Tetracarpidium conophorum Müll. Arg. Supplemented Diet Improved Testosterone Levels, Modulated Ectonucleotidases and Adenosine Deaminase Activities in Platelets from L-NAME-Stressed Rats Olabiyi AA, Morsch VM, Oboh G, Schetinger MRC
Experimental Study High Blood Pressure Testosterone Tiger Nut
Rats were used in the experiment, placed into seven distinct groups with various diet and medicinal intake combinations including basal diet controls, supplemented processed and raw tiger nut (TN) and walnut (WN) diets, and more. Before hypertension was induced with L-NAME, the rats were given their regular diet for two weeks. After this period, they began receiving L-NAME for ten subsequent days. The scientists then measured the impacts on the rats' platelet androgen levels, ectonucleotidases, and adenosine deaminase (ADA).
The L-NAME treatment resulted in a considerable decline in testosterone levels in the rats. However, the groups that were fed diets supplemented with TN and WN exhibited improved testosterone levels compared to the control group, yet their luteinizing hormone levels remained unchanged.
The L-NAME-treated group also saw an increase in ATP hydrolysis and ADA activity, alongside a reduction in ADP and AMP hydrolysis. These effects were substantially reversed in the groups that were fed supplemented TN and WN diets. This suggests that TN and WN could enhance testosterone levels and modulate the purinergic system in platelets, which might be a potential mechanism through which they contribute to the control of vasoconstriction.
Strawberry interventions significantly reduced CRP levels and may improve total cholesterol and LDL-cholesterol in individuals with high baseline levels.
2020 British Journal of Nutrition Effects of strawberry intervention on cardiovascular risk factors: a meta-analysis of randomised controlled trials Gao Q, Qin LQ, Arafa A, Eshak ES, Dong JY
Meta-Analysis Cholesterol CRP LDL
We included eleven RCT in this meta-analysis (six for blood pressure, seven for lipid profile, seven for fasting blood glucose and six for C-reactive protein (CRP)). Overall, the strawberry interventions significantly reduced CRP levels by 0·63 (95 % CI −1·04, −0·22) mg/l but did not affect blood pressure, lipid profile or fasting blood glucose in the main analyses. Our analysis stratified by baseline endpoint levels showed the strawberry interventions significantly reduced TC among people with baseline levels >5 mmol/l (−0·52 (95 % CI −0·88, −0·15) mmol/l) and reduced LDL-cholesterol among people with baseline levels >3 mmol/l (−0·31 (95 % CI −0·60, −0·02) mmol/l). There was little evidence of heterogeneity in the analysis and no evidence of publication bias.
Incorporating daily doses of walnuts into the diet of elderly individuals significantly reduces the concentrations of several inflammatory biomarkers.
2020 Journal of the American College of Cardiology Effects of 2-Year Walnut-Supplemented Diet on Inflammatory Biomarkers Cofán M, Rajaram S, Sala-Vila A, Valls-Pedret C, Serra-Mir M, Roth I, et al.
Randomised Controlled Trial Anti-Inflammatory Cholesterol Walnut
This study followed the WALHA study protocol and involved 708 elderly participants from two centers, one in Barcelona, Spain, and another in Loma Linda, California. They were randomly assigned into two groups: one group incorporated walnuts, at least 15% of energy (30 to 60g per day), into their diets, while the other group abstained from walnuts. The participants visited dietitians every two months for advice to maintain their allocated diets and physical activity level. The walnut group received 8-week allotments of raw-piece walnuts in sachets for daily consumption. The researchers conducted assessments of inflammatory biomarkers at the start and end of this 2-year study.
Differences in the changes of inflammatory markers between diets were analyzed using multivariate-adjusted analysis of covariance. Of the 634 participants who completed the study, 66% were women and 32% were on statins. The average age was 69 years. There were no changes in body weight throughout the trial. Incorporation of walnuts into the diet resulted in significantly reduced concentrations of six out of ten examined biomarkers. Changes in inflammatory molecules were not related to changes in the main food groups.