Vitamin D Intake Attenuated the Association between Pesticides Exposure and Female Infertility.

BACKGROUND: Only a few epidemiological studies have illuminated the association between pesticide exposure and female infertility. However, evidence of the available data is restricted and also controversial. Vitamin D supplement was considered as having a beneficial effect on fertility. So, the purpose of our study is to assess the effect of dietary vitamin D consumption on the relationship between pesticide exposure in home and female infertility. METHODS: There were a total of 2,968 subjects from the National Health and Nutrition Examination Survey (NHANES), 2011 - 2018. The daily vitamin D intake was divided into two groups high intake (≥ 6 µg/d) and low intake (< 6 µg/d). Multi-variable logistic regression analysis was used to assess the relationship among vitamin D intake, pesticide exposure, and female infertility. RESULTS: We found a significant association between household pesticide exposure and infertility on a basis of a fully-adjusted model (OR 1.61; 95% CI 1.1 - 2.37). Furthermore, the relationship between pesticide exposure and in-fertility differed from low vitamin D intake group (OR 3.96; 95% CI 1.77 - 8.86) and high intake group (OR 1.36, 95% CI: 0.86 - 2.16), and p for interaction is 0.043 stratified by vitamin D intake. CONCLUSIONS: A significant association of female infertility with pesticide exposure in home is modified by dietary vitamin D consumption. This was the first study to demonstrate that dietary vitamin D may alter associations of human female infertility with pesticide exposure in home.

Antioxidant and Cytoprotective Effects of Tibetan Tea and Its Phenolic Components.

Tibetan tea (Kangzhuan) is an essential beverage of the Tibetan people. In this study, a lyophilized aqueous extract of Tibetan tea (LATT) was prepared and analyzed by HPLC. The results suggested that there were at least five phenolic components, including gallic acid, and four catechins (i.e., (+)-catechin, (-)-catechin gallate (CG), (-)-epicatechin gallate (ECG), and (-)-epigallocatechin gallate). Gallic acid, the four catechins, and LATT were then comparatively investigated by four antioxidant assays: ferric reducing antioxidant power, 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide radical (PTIO•) scavenging, 1,1-diphenyl-2-picryl-hydrazl radical scavenging, and 2,2'-azino-bis(3-ethylbenzo-thiazoline-6-sulfonic acid) radical scavenging assays. In these assays, LATT, along with the five phenolic components, increased their antioxidant effects in a concentration-dependent manner; however, the half maximal scavenging concentrations of ECG were always lower than those of CG. Gallic acid and the four catechins were also suggested to chelate Fe2+ based on UV-visible spectral analysis. Ultra-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UPLC-ESI-Q-TOF-MS/MS) analysis suggested that, when mixed with PTIO•, the five phenolic components could yield two types of radical adduct formation (RAF) products (i.e., tea phenolic dimers and tea phenolic-PTIO• adducts). In a flow cytometry assay, (+)-catechin and LATT was observed to have a cytoprotective effect towards oxidative-stressed bone marrow-derived mesenchymal stem cells. Based on this evidence, we concluded that LATT possesses antioxidative or cytoprotective properties. These effects may mainly be attributed to the presence of phenolic components, including gallic acid and the four catechins. These phenolic components may undergo electron transfer, H⁺-transfer, and Fe2+-chelating pathways to exhibit antioxidative or cytoprotective effects. In these effects, two diastereoisomeric CG and ECG showed differences to which a steric effect from the 2-carbon may contribute. Phenolic component decay may cause RAF in the antioxidant process.