Can different types of tree nuts and peanuts induce varied effects on specific blood lipid parameters? A systematic review and network meta-analysis.

Tree nuts and peanuts have shown cardioprotective effects through the modulation of blood lipid levels. Despite the abundance of scientific evidence available, it remains uncertain whether the type of nut consumed influences these changes. The objective of this study was to evaluate and rank the effects of six types of nuts on total cholesterol (total-c), low-density lipoprotein (LDL-c), triglyceride (TG) and high-density lipoprotein (HDL-c) levels through a systematic search of randomized controlled trials (RCTs), a frequentist network meta-analysis (NMA), and the estimation of SUCRA values. A total of 76 RCTs were ultimately analyzed. The total c for pistachios, almond, and walnuts; LDL-c for cashews, walnuts, and almond; and TG for hazelnuts and walnuts significantly decreased, while only peanuts exhibited a significant increase in HDL-c levels. According to the rankings, the most effective type of nut for reducing total cholesterol was pistachio, cashew for LDL-c, hazelnut for TG, and peanut for increasing HDL-c levels. It should be noted that every type of nut analyzed exhibited a significant positive impact on some parameters, and specific types demonstrated enhanced advantages for particular blood lipids. These results endorse the use of personalized nutritional strategies to address and prevent dyslipidemia.Registration: PROSPERO database CRD42021270779.

Association of nut consumption with insulin resistance and blood lipid profile in Spanish university students.

AIMS: To examine whether nut consumption was associated with insulin resistance and blood lipid parameters in a sample of young healthy adults. MATERIAL AND METHODS: A cross-sectional study was conducted involving 306 first-year students (aged 18-30 years) from the University of Castilla-La Mancha, Spain. Biochemical variables related to insulin resistance and blood lipid profile (glucose, insulin, HbA1c, total cholesterol (total-c), LDL-c, HDL-c, and triglycerides) were determined from morning fasting blood samples. Nut consumption was estimated using a 137-item Food-Frequency Questionnaire. The associations of walnuts, other nuts and total nut intakes with insulin resistance and lipid profile variables and surrogates were assessed by linear regression analysis. Differences in insulin resistance and lipid profiles between participants meeting or not meeting the nut consumption recommendations were examined by analysis of covariance (ANCOVA). Logistic regressions were used to analyze the likelihood of having higher levels of blood lipids or insulin resistance in participants who met or did not meet the recommended intake of nuts. RESULTS: There was no association found between nut consumption, whether walnuts or other nut varieties, and insulin resistance and lipid profile variables. Additionally, there were no significant differences in insulin resistance or blood lipid profile variables between university students meeting or not meeting nut consumption recommendations. Finally, stratified analyses based on sex were consistent and did not substantially modify our estimates in the fully adjusted models. CONCLUSIONS: In conclusion, our results suggest that walnuts, other types of nuts, and total nut consumption did not adversely influence metabolic or lipid profile variables among healthy young adults. Although nuts are recommended among healthy dietary patterns, our findings showed that nut consumption has a null effect on the cardiometabolic risk parameters explored in young healthy adults.

The associations between adherence to the Mediterranean diet and physical fitness in young, middle-aged, and older adults: A protocol for a systematic review and meta-analysis.

INTRODUCTION: A healthy diet and high health-related physical fitness levels may be part of an overall healthy lifestyle. The relationship between adherence to the Mediterranean diet and physical fitness levels has been analyzed in several studies. However, no studies have synthesized evidence on this relationship throughout adulthood. Moreover, in addition to the overall Mediterranean dietary pattern, the associations of individual components of the Mediterranean diet with physical fitness indicators are also unclear. METHODS: This protocol for a systematic review and meta-analysis was conducted according to the Preferred Reporting Items for Systematic Review and Meta-Analysis for Protocols statement and the Cochrane Collaboration Handbook. Systematic literature searches will be performed in the MEDLINE (PubMed), Scopus, Web of Science, SPORTDiscus and Cochrane CENTRAL databases to identify studies published up to 31 January 2022. The inclusion criteria will comprise observational studies and randomized controlled trials reporting the associations between adherence to the Mediterranean diet and physical fitness levels on general healthy or unhealthy adults (≥18 years). When at least five studies addressing the same outcome are available, meta-analysis will be carried out to estimate the standardized mean difference of physical fitness according to the adherence to Mediterranean diet. Subgroup analyses will be performed according to the characteristics of the population, the individual dietary components of the Mediterranean diet and physical fitness parameters as long as there are sufficient studies. ETHICS AND DISSEMINATION: This systematic review and meta-analysis protocol is designed for updating evidence on the associations between adherence to overall Mediterranean diet (and specific Mediterranean foods) and physical fitness levels in young, middle-aged, and older adults. Findings from this review may have implications for public health. The results will be disseminated through peer-reviewed publication, conference presentation, and infographics. No ethical approval will be required since only published data will be used. PROSPERO REGISTRATION NUMBER: CRD42022308259.

The Comparative Effects of Different Types of Oral Vitamin Supplements on Arterial Stiffness: A Network Meta-Analysis.

Arterial stiffness, a significant prognostic factor of cardiovascular disease, may be affected by dietary factors. Research on the effects of oral vitamin supplements on arterial stiffness and/or endothelial function has produced controversial results. Therefore, the aim of this network meta-analysis was to comparatively assess the effect of different types of oral vitamin supplements on arterial stiffness in the adult population. We searched the PubMed, Embase, Cochrane Library, and Web of Science databases for randomized controlled trials from their inception to 30 September 2021. A network meta-analysis using a frequentist perspective was conducted to assess the effects of different types of oral vitamin supplements on arterial stiffness, as determined by pulse wave velocity. In total, 22 studies were included, with a total of 1318 participants in the intervention group and 1115 participants in the placebo group. The included studies were listed in an ad hoc table describing direct and indirect comparisons of the different types of vitamins. Our findings showed that, in both pairwise comparison and frequentist network meta-analysis, the different types of oral vitamin supplements did not show statistically significant effects on arterial stiffness. However, when oral vitamin supplementation was longer than 12 weeks, vitamin D3 showed a significant reduction in arterial stiffness, compared with the placebo (ES: -0.15; 95% CI: -0.30, -0.00; -60.0% m/s) and vitamin D2 (ES: -0.25; 95% CI: -0.48, -0.02, -52.0% m/s). In summary, our study confirms that oral vitamin D3 supplementation for more than 12 weeks could be an effective approach to reduce arterial stiffness and could be considered a useful approach to improve vascular health in patients at high risk of cardiovascular disease.

The Role of Physical Fitness in the Relationship between Nut Consumption and Body Composition in Young Adults.

The main objective of this study was to estimate the association between nut consumption and body composition-related measures and to examine whether this relationship is mediated by cardiorespiratory fitness (CRF) and the muscle strength index (MSI) in young adults. A cross-sectional study involving college students (n = 354) aged 18-30 years from a Spanish public university was conducted. Body composition and fitness components were assessed using standard methods. Nut consumption was evaluated using a Food-Frequency Questionnaire. ANCOVA models were used to assess the mean differences in physical fitness and body composition by nut consumption categories. Hayes's PROCESS macro was applied for mediation and interaction analyses adjusted for the main confounders. Young adults with high nut consumption (≥5 portions of 30 g/week) showed significantly higher values of physical fitness components and fat-free mass and lower values of adiposity-related measures than their peers in the lowest categories of nut consumption (˂1 portion/week) (p < 0.05). No significant interaction between CRF and nut consumption on body composition was found. In the mediation analysis, CRF and MSI acted as full mediators of the relationship of nut consumption with fat-free mass and waist circumference/height index. Otherwise, CRF and MSI partially mediated the relationship between nut consumption and body mass index and percent of fat mass. Finally, nut consumption, per se, does not appear to have a significant impact on body composition indicators because these associations have been shown to be partially (for BMI and %BF) or entirely (for ratio WC/height and fat-free mass) explained by CRF and MSI.