ABSTRACT
CONTEXT: Although some research suggests that vitamin B12 (hereafter, B12) supplements can lower homocysteine (Hcy) levels and treat hyperhomocysteinemia, these results are still ambiguous when B12 is taken as an isolated supplement. OBJECTIVE: This study sought to determine how existing randomized controlled trials (RCTs) could be used to examine the effects of B12 supplementation on Hcy. DATA SOURCES: To find pertinent RCTs up to June 2022, databases, including PubMed/Medline, Web of Science, Scopus, Cochrane Library, and Embase, were searched. DATA EXTRACTION: All selected RCTs investigated the impact of B12 supplements on Hcy. A meta-analysis of the eligible studies was performed using the random-effects model. DATA ANALYSIS: This review included a total of 21 RCTs (N = 1625 participants). Hcy levels were significantly lower after B12 supplementation compared with the control group (pooled weighted mean difference, -4.15 µmol/L; 95% confidence interval, -4.86, -3.45; P < 0.001), and this reduction was even greater with intervention durations ≥12 weeks and doses >500 µg/d. Furthermore, the effect of B12 supplementation in the form of hydroxocobalamin on the reduction of Hcy level was greater compared with other forms. CONCLUSION: In conclusion, this meta-analysis shows that B12 supplementation has a positive impact on lowering blood Hcy levels, particularly when administered for a longer period and at a larger dose. SYSTEMATIC REVIEW REGISTRATION: PROSPERO registration no. CRD42022364066.
ABSTRACT
Background: Evidence suggests the role of changing traditional lifestyle patterns, such as Paleolithic, to the modern lifestyle in the incidence and epidemic of chronic diseases. The purpose of this study was to investigate the associations between the Paleolithic diet (PD) and the Paleolithic-like lifestyle and the risk of non-alcoholic fatty liver disease (NAFLD) among an adult population. Materials and Methods: This case-control study was carried out among 206 patients with NAFLD and 306 healthy subjects aged >18 years. PD score was evaluated using a validated 168-item quantitative food frequency questionnaire. In addition, to calculate the Paleolithic-like lifestyle score, the components of physical activity, body mass index (BMI), and smoking status of the participants were combined with the score of the PD. Results: The mean PD and Paleolithic-like lifestyle scores were 38.11 ± 5.63 and 48.92 ± 6.45, respectively. After adjustment for potential confounders, higher scores of adherence to the PD diet conferred a protection for the presence of NAFLD [odds ratio (OR): 0.53; 95% confidence interval (CI): 0.28-0.98; P for trend = 0.021]. Furthermore, PD and healthy lifestyle habits were negatively associated with NAFLD (OR = 0.42, 95% CI 0.23-0.78; P for trend = 0.007). Conclusion: Our data suggest that the PD alone and in combination with lifestyle factors was associated with decreased risk of NAFLD in a significant manner in the overall population. However, prospective studies are needed to further investigate this association.
