Higher dietary total antioxidant capacity (TAC) reduces the risk of cardio-metabolic risk factors among adults: An updated systematic review and meta-analysis

Dietary total antioxidant capacity and risk of stroke: a systematic review and dose-response meta-analysis of observational studies

Background

Previous studies have reported the association between dietary total antioxidant capacity (TAC) and risk of stroke, but these findings have been inconsistent. We therefore performed this systematic review and dose–response meta-analysis of observational studies to evaluate the association between dietary TAC and risk of stroke.

Methods

A systematic literature search was carried out through PubMed, ISI Web of Science, EBSCO, Scopus and China National Knowledge Infrastructure (CNKI) databases, to find the relevant articles published up to 31 May, 2024. Random-effects or fixed-effects models were used to pool the relative risks (RRs) and their 95% confidence intervals (CIs) where appropriate. Heterogeneity across studies were determined using the Cochran’s Q test and I-square (I2) statistics.

Results

Eight observational studies (six cohort and two case–control studies) were included in the final analysis. The pooled results showed that higher intake of dietary TAC was associated with a lower risk of stroke (RR = 0.88; 95%CI: 0.81–0.95, p = 0.002). Additionally, dose–response analysis of cohort studies demonstrated a linear association between dietary TAC intake and risk of stroke (RR = 0.994; 95%CI: 0.990–0.999, Pnon-linearity = 0.329, Pdose–response = 0.014). Subgroup analyses showed the inverse association between dietary TAC intake and risk of stroke in the studies with mean age < 50 (RR = 0.82, 95%CI: 0.67–0.99, p = 0.044), and there was no evidence of heterogeneity (p = 0.360; I2 = 0.0%).

Conclusion

Our findings indicated that higher intake of dietary TAC was inversely associated with the risk of stroke. Future studies in particular of longitudinal design are needed to confirm this inverse relationship.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42024547706.

Association between dietary antioxidant indices and hypertension among Chinese adults

The effect of dietary antioxidants on blood pressure (BP) regulation and hypertension risk remains largely unknown. This study aimed to comprehensively assess the impacts of dietary antioxidants on systolic BP (SBP), diastolic BP (DBP), mean arterial pressure (MAP), and pulse pressure (PP), and hypertension risk among Chinese adults. The cross-sectional study assessed data from 12,046 Chinese adults, evaluating dietary antioxidant quality scores (DAQS) and total antioxidant capacity (DTAC) via a validated food frequency questionnaire. MAP was derived using the formula DBP + (0.412 ×PP), with PP calculated as SBP - DBP. The relationship between DAQS, DTAC, and hypertension prevalence was analyzed using multivariable logistic regression. Among participants not taking antihypertensive medications, those in the highest groups of DTAC and DAQS had significantly lower SBP, DBP, MAP, and PP compared to those in the lowest groups (all p-trends <0.001). Relative to the lowest quintile (Q1) of DTAC (adjusted odds ratios (OR) for hypertension decreased in Q2 (OR 0.90, 95%CI 0.79-1.03), Q3 (OR 0.65, 95% CI 0.56-0.76), Q4 (OR 0.51, 95% CI 0.43-0.60), and Q5 (OR 0.38, 95% CI 0.31-0.46) (p trend <0.001). For DQAS, hypertension OR of category 5 was 0.38 (95% CI 0.32-0.46) compared to that of category 1. Increased vitamin A, Zinc, and selenium intake correlated with reduced hypertension risk. A significant non-linear DTAC and linear DAQS relationships were observed and hypertension risk. Antioxidant-rich diets markedly lowered SBP, DBP, MAP, PP, and hypertension risk.

Modulation of gut microbiota and markers of metabolic syndrome in mice on cholesterol and fat enriched diet by butterfly pea flower kombucha

Clitoria ternatea, with an alternative name, Butterfly pea, is increasingly being explored for medical purposes and the development of a wide range of processed products. This study aimed to incorporate Butterfly pea into an innovative probiotic drink through a symbiotic culture of bacteria and yeast (SCOBY) fermentation and to evaluate the biological activity. The benefits of the drink, referred to as butterfly pea flower kombucha (KBPF) was determined in vitro and in metabolically disorder mice that receive a diet rich in cholesterol and fat (CFED). Forty white male were categorized into four groups, i.e., A = Control/Normal Diet; B = CFED alone; C = CFED + KBPF 65 mg/kg BW (Body Weight); D = CFED + KBPF 130 mg/kg BW, and then sacrificed after 6 weeks of intervention. Seventy-nine secondary metabolite compounds were successfully identified in KBPF using LC-HRMS. In vitro studies showed the potential activity of KBPF in inhibiting not only ABTS, but also lipid (lipase) and carbohydrate (α-amylase, α-glucosidase) hydrolyzing enzymes to levels similar to acarbose control at 50–250 μg/mL. In the in vivo study, the administration of KBPF (130 mg/kg BW) significantly alleviated metabolic disorders caused by high-fat diet. Specifically, lipid profile (HDL, LDL, TC, TG), blood glucose, markers of oxidative stress (SOD liver), metabolic enzymes (lipase, amylase), and markers of inflammation (PGC-1α, TNF-α, and IL-10) were in most cases restored to normal values. Additionally, the gut microbiota community analysis showed that KBPF has a positive effect (p = 0.01) on both the Bacteroidetes phylum and the Firmicutes phylum. The new KBPF drink is a promising therapeutic functional food for preventing metabolic diseases.

•

Clitoria ternatea or Butterfly pea flower processed or innovated into a functional probiotic drink, namely KBPF.

•

A total of 79 Secondary metabolite compounds of KBPF were successfully identified.

•

In vitro studies showed the potential activity of KBPF in inhibiting ABTS, lipase, α-glucosidase, and α-amylase.

•

Administering a dose of 130 mg/kg BW KBPF was significantly promising in the alleviation of biomarker metabolic disorders with immunomodulatory effects.

•

By modulating the diversity of the gut microbiome, KBPF can be a promising nutraceutical in preventing metabolic syndrome with inflammatory diseases.