A systematic review of randomized controlled trials related to the effects of garlic supplementation on platelet aggregation.

The increment of platelet aggregation factors has been considered a key phenomenon in atherosclerosis. Studies have shown that garlic (Allium sativum) is associated with a reduction in platelet aggregation and thrombosis. Hence, the present systematic review was conducted to evaluate the effect of garlic on platelet aggregation. All randomized controlled trials (RCTs) with keywords related to garlic and platelet aggregation were thoroughly searched in electronic databases including PubMed, Scopus, ISI Web of Science, and Google Scholar up to January 2021. Moreover, the references of all related articles were screened to discover more relevant studies. The quality of each study was reported based on Cochrane Collaboration's tool. In total, 12 studies met the inclusion criteria from 18,235 identified articles (including 595 participants). Most of the studies assessed platelet aggregation in response to different inducers. Of the 12 clinical trials, six studies depicted the beneficial effect of garlic on reducing platelet aggregation. The summary of the quality assessment indicated that most of the studies had high-quality scores. Regarding the small number of RCTs and heterogeneity between studies, it is impossible to make a proper conclusion about the impacts of garlic on platelet aggregation. Therefore, further precise trials with a standard design are necessary to validate the anti-thrombotic effect of garlic.

Effect of hypocaloric high-protein, low-carbohydrate diet supplemented with fennel on androgenic and anthropometric indices in overweight and obese women with polycystic ovary syndrome: A randomized placebo-controlled trial.

OBJECTIVE: The aim of this study was to evaluate the effect of hypocaloric high-protein, low-carbohydrate weight loss diet supplemented with fennel on anthropometric and androgen indices in overweight and obese women with polycystic ovary syndrome (PCOS). METHODS: A randomized controlled trial with a factorial design was performed on sixty-four overweight/obese women with PCOS. Participants were randomly allocated to four groups (n = 16 per group) as follows: 1) hypocaloric standardize diet + fennel (2 capsule/day) (HSDF), 2) hypocaloric high-protein diet + fennel (2 capsule/day) (HHPF), 3) hypocaloric standardize diet + placebo (HSDP), and 4) hypocaloric high-protein diet + placebo (HHPP). RESULTS: The mean (SD) age of the participants was 28.54 (6.80) years and body mass index was 32.24 (4.65) kg/m2. At the end of intervention, protein intake was 20.43 % in the groups that received a high-protein diet versus 16.37 % in the standard diet groups (P < 0.001). Combination of hypocaloric high-protein diet and fennel capsule did not significantly affect change in outcomes compared with groups not receiving them. There was a significant interaction between hypocaloric high-protein diet and fennel on weight (P = 0.019). CONCLUSION: A hypocaloric high-protein diet along with fennel supplementation could not provide additional improvements in anthropometric and androgen indices among PCOS women. Further studies are required to more precisely elucidate these findings.

The effect of vitamin D supplementation on the androgenic profile in men: A systematic review and meta-analysis of clinical trials.

The aim of this systematic review and meta-analysis was to evaluate the effect of vitamin D supplementation on total testosterone (TT) and sex hormone-binding globulin (SHBG) in men. We searched PubMed, Scopus and Web of Science for randomized, controlled trials of vitamin D supplementation in men ≥18 years old up to September 2018, without language restrictions. Meta-analysis was based on a random effects model. The systematic review was registered as CRD42018094498. We identified 3,402 articles, of which eight studies with 10 effect sizes met the inclusion criteria. Vitamin D daily dose equivalents ranged from 600 to 4,000 per day to 60,000 IU per week; duration was 6 weeks to 36 months. In general, vitamin D supplementation had no significant effect on TT (MD = 0.20, 95% CI: -0.20, 0.60, p = 0.336) and SHBG (MD = 1.56, 95% CI: -0.85, 3.97, p = 0.204). Subgroup analysis conducted with duration of prescription, type (daily or weekly), dosing frequency and baseline vitamin D and TT concentration showed that vitamin D did not significantly affect TT. The present study did not find any evidence to support beneficial effect of vitamin D supplementation on TT and SHBG in men. Thus, further large-scale randomised controlled trials are required to evaluate the effects of vitamin D supplementation on androgen in men.