Effects of NAD+ precursors on blood pressure, C-reactive protein concentration and carotid intima-media thickness: A meta-analysis of randomized controlled trials.

BACKGROUND: There are contradictory effects regarding the effect of NAD+ precursor on blood pressure and inflammation. In order to obtain a better viewpoint from them, this study aimed to comprehensively investigate the effects of NAD+ precursor supplementation on blood pressure, C-reactive protein (CRP) and carotid intima-media thickness (CIMT). METHODS: PubMed/MEDLINE, Web of Science, SCOPUS and Embase databases were searched using standard keywords to identify all controlled trials investigating the effects of NAD+ precursor on blood pressure, CRP and CIMT. Pooled weighted mean difference (WMD) and 95% confidence intervals (95% CI) were achieved by random-effects model analysis for the best estimation of outcomes. RESULTS: Twenty-nine articles (with 8664 participants) were included in this article. Results from meta-analyses of RCTs from random-effects models indicated a significant reduction in systolic (SBP) (weighted mean difference (WMD): -2.54 mmHg, p < .001) and diastolic blood pressure (DBP) (WMD: -2.15 mmHg, p < .001), as well as in CRP (WMD: -.93 mg/L, 95% CI -1.47 to -.40, p < .001) concentrations and CIMT (WMD: -.01 mm, 95% CI -.02 to -.00, p = .005) with the NAD+ precursors supplementation compared with the control group. In addition, a greater effect of supplementation with NAD+ precursors in reducing blood pressure (BP) were observed with the highest dose (≥2 g) and duration of the intervention (>12 weeks), as well as with NA supplementation when compared to NE. CONCLUSIONS: Overall, these findings suggest that NAD+ precursor supplementation might have a beneficial effect on cardiovascular risk factors such as BP, CRP concentration and CIMT.