Associations of Dietary Zinc-Vitamin B6 Ratio with All-Cause Mortality and Cardiovascular Disease Mortality Based on National Health and Nutrition Examination Survey 1999-2016

Previous studies have suggested a possible association among dietary zinc and vitamin B6 intake and CVD mortality and all-cause mortality. However, evidence on the association of dietary zinc and vitamin B6 intake and their interactions with CVD mortality and all-cause mortality remains unclear. This prospective study utilized data from the US National Health and Nutrition Examination Survey (NHANES) from 1999 to 2016. After a median follow-up of 10.4 years, 4757 deaths were recorded among 36,081 participants. Higher dietary zinc intake levels (≥9.87 mg/day) were associated with lower CVD mortality (hazard ratio (HR) = 0.85, 95% confidence interval (CI): 0.83−0.87). Vitamin B6 intake levels (≥1.73 mg/day) were associated with lower CVD mortality (HR = 0.91, 95% CI: 0.86−0.96) and all-cause mortality (HR = 0.91, 95% CI: 0.90−0.93). Higher dietary zinc intake and higher vitamin B6 intake were associated with a lower risk of CVD mortality, with an interaction between dietary zinc intake levels and vitamin B intake levels (LZLV group (HR, CI): 1.21,1.12−1.29; LZHV group (HR, CI): 1.42, 1.34−1.50; LZHV group (HR, CI): 1.28, 1.14−1.45; HZHV group (HR, CI): ref). There was also a J-type association (p for nonlinear < 0.001) between the dietary zinc−vitamin B6 ratio and CVD mortality, with a high dietary zinc−vitamin B6 ratio increasing the risk of CVD mortality (HR = 1.27, 95% CI: 1.19−1.35), whereas a moderate dietary zinc−vitamin B6 ratio appeared to be beneficial for CVD mortality. These results suggest that increasing the appropriate proportion of dietary zinc and vitamin B6 intake is associated with a lower risk of CVD mortality. Furthermore, precise and representative studies are needed to verify our findings.

Associations of dietary vitamin B1, vitamin B2, vitamin B6, and vitamin B12 with the risk of depression: a systematic review and meta-analysis

CONTEXT

The results from epidemiologic studies on the intake of dietary vitamin B1, B2, B6, and B12 and association with risk of developing depression have been inconsistent.

OBJECTIVE

The purpose of this systematic review and meta-analysis was to summarize the existing evidence and synthesize the results.

DATA SOURCES

The databases of Web of Science and PubMed were searched for relevant articles published in English until September 2020.

STUDY SELECTION

Observational studies that evaluated the associations between depression and dietary vitamin B1, B2, B6, and B12 were included in this study.

DATA EXTRACTION

The job of data extraction was undertaken by 2 authors, and the pooled relative risks (RRs) and 95% confidence intervals (CIs) were calculated using a fixed-effects model.

RESULTS

Thirteen articles related to 18 studies were eligible for inclusion in this systematic review and meta-analysis. The pooled RR (95% CI) of depression for the highest vs the lowest category of dietary vitamin B1, B2, B6, and B12 was 0.69 (0.55-0.87), 0.77 (0.67-0.89), 0.81 (0.71-0.93), and 0.86 (0.75-0.99), respectively. The pooled RR (95% CI) of depression for the highest vs the lowest category of dietary vitamin B2 was 0.80 (0.64-0.99) in females and 0.83 (0.67-1.02) in males, for dietary vitamin B6 was 0.71 (0.59-0.86) in females and 0.92 (0.76-1.12) in males, and for dietary vitamin B12 was 0.79 (0.65-0.97) in females and 0.94 (0.77-1.15) in males.

CONCLUSION

This study suggested that the intake of dietary vitamin B1, B2, B6, and B12 may be inversely associated with the risk of depression; the inverse associations observed between depression and intake of dietary vitamin B2, B6, and B12 were significant in females, but not in males. Further studies are needed to confirm these results.