ABSTRACT
Background: Deficiency in vitamin D has been shown to increase the risk of injury. Purpose: To synthesize current placebo-controlled randomized trials investigating the effect of vitamin D supplementation in elite athletes on (1) aerobic capacity; (2) anaerobic measures, such as strength, speed, and anaerobic power; (3) serum biomarkers of inflammation; and (4) bone health. Study Design: Systematic review; Level of evidence, 1. Methods: A literature search was conducted on November 30, 2022, according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Included were randomized, placebo-controlled studies of longer than 2 weeks on subjects with active participation in organized sport. Excluded were nonrandomized controlled trial study designs, vitamin D administration routes other than oral, studies that did not use vitamin D supplementation as the sole intervention, and studies with nonathletic or military populations. Results: Out of 2331 initial studies, 14 studies (482 athletes) were included. Of the 3 studies that assessed aerobic capacity, 2 demonstrated significantly greater improvements in maximal oxygen uptake and physical working capacity-170 (P < .05) in supplemented versus nonsupplemented athletes. Measurements of anaerobic power and strength were consistently increased in supplemented groups compared with nonsupplemented groups in 5 out of the 7 studies that assessed this. Of the 6 studies that assessed sprint speed, 4 found no significant difference between supplemented and nonsupplemented groups. Aside from 1 study that found significantly lower interleukin-6 levels in supplemented athletes, measures of other inflammatory cytokines were not affected consistently by supplementation. The 4 studies that assessed markers of bone health were conflicting regarding benefits of supplementation. One study found demonstrated improvements in bone mineral density in response to supplementation (P = .02) compared with control whereas another found no significant difference between supplemented and nonsupplemented groups. However, in 3 other studies, serum biomarkers of bone turnover such as bone-specific alkaline phosphatase, parathyroid hormone, and N-terminal telopeptide appeared to be higher in subjects with lower serum vitamin D levels (P < .05). Conclusion: Results of this systematic review indicated that the greatest benefit of vitamin D supplementation in elite athletes may be improving aerobic endurance, anaerobic power, and strength. More research is needed to determine the effect of vitamin D supplementation on bone health and injury risk in this population.
ABSTRACT
Diabetes is an increasingly problematic health concern in the United States. Moringa oleifera (M. oleifera) has been suggested as medication in the prevention or treatment of diabetes, but there is no convincing evidence of a causal relation between moringa and decreased blood sugar levels in humans. The purpose of this scoping review is to examine the effects of Moringa oleifera on blood glucose levels in rats and humans. A search of Scopus, Ovid Medline, Ovid Embase, IPA, and Web of Science and manual searching of bibliographies were performed for peer-reviewed English articles published between May 1, 2008 and May 1, 2018. This review included thirty studies. Out of seven human studies, five found that M. oleifera significantly reduced blood glucose levels in diabetic patients. Out of twenty-three animal studies, twenty-one found that administration of M. oleifera led to a statistically significant decrease in animal blood glucose levels. In human studies, moringa was mostly administered in a powdered leaf form, while in animal studies it was frequently administered to as an aqueous or ethanol-based extract. The review found statistical evidence that moringa decreased blood glucose; the evidence is not strong enough to recommend it as the default treatment for people with diabetes.