Dietary Supplement Use among Iranian Households during COVID-19 Epidemic Lockdown: Less Access in Those Who May Need More National Food and Nutrition Surveillance.

Background: The coronavirus disease 2019 (COVID-19) pandemic elicited the general population to use various dietary supplements (DSs) and nutraceuticals as a protective means against the disease. The present study aimed to evaluate changes and certain determinants of DS intake during the COVID-19 lockdown among Iranian households. Methods: This nationwide cross-sectional study was conducted from April 4 to April 25, 2020, during which Iran was in lockdown. To collect data, a web-based electronic self-administered questionnaire was created. The data were compared among provinces based on their food security situations. Results: A total of 21,290 households were included in the analyses. Approximately 27% of the households were using DSs after the epidemic. The most common DSs used were vitamin D (42%) and vitamin C (20%), followed by multi-vitamin (16%), zinc (9%), omega-3 (6%), vitamin A (4%), and probiotics (3%). Logistic regression analysis revealed that DS intake was directly associated with the household income but inversely with household size and the food security status of the provinces. DS intake was positively associated with the presence of high-risk persons in the households, the education of the households' head, and the presence of a person with a history of COVID-19 within the household. Conclusions: During epidemic lockdown, DS use was remarkably increased among the Iranian households. Apart from the debatable usefulness of DSs against COVID-19, the inverse association of DS use with a household's income and provincial food security well indicates inequity in accessibility to DS. Actions to improve the nutritional status of the under-privileged populations including targeted supplementation are strongly recommended.

Effect of vitamin E intake on glycemic control and insulin resistance in diabetic patients: an updated systematic review and meta-analysis of randomized controlled trials.

Since a 2014 meta-analysis, several randomized controlled trials (RCTs) evaluating the effect of vitamin E intake on glycemic indices and insulin resistance in adults with diabetes have reached inconsistent conclusions. Therefore, we updated the previous meta-analysis to summarize the current evidence in this regard. Online databases including PubMed, Scopus, ISI Web of Science, and Google Scholar were searched to identify relevant studies published up to September 30, 2021, using relevant keywords. Random-effects models were used to obtain overall mean difference (MD) comparing vitamin E intake with a control group. In total, 38 RCTs with a total sample size of 2171 diabetic patients (1110 in vitamin E groups and 1061 in control groups) were included. Combining the results from 28 RCTs on fasting blood glucose, 32 RCTs on HbA1c, 13 RCTs on fasting insulin, and 9 studies on homeostatic model assessment for insulin resistance (HOMA-IR) showed a summary MD of -3.35 mg/dL (95% CI: -8.10 to 1.40, P = 0.16), -0.21% (95% CI: -0.33 to -0.09, P = 0.001), -1.05 µIU/mL (95% CI: -1.53 to -0.58, P < 0.001), and -0.44 (95% CI: -0.82 to -0.05, P = 0.02), respectively. This indicates a significant lowering effect of vitamin E on HbA1c, fasting insulin and HOMA-IR, while no significant effect on fasting blood glucose in diabetic patients. However, in subgroup analyses, we found that vitamin E intake significantly reduced fasting blood glucose in studies with an intervention duration of < 10 weeks. In conclusion, vitamin E intake has a beneficial role in improving HbA1c and insulin resistance in a population with diabetes. Moreover, short-term interventions with vitamin E have resulted in lower fasting blood glucose in these patients. This meta-analysis was registered in PROSPERO with code CRD42022343118.

Phylloquinone supplementation improves glycemic status independent of the effects of adiponectin levels in premonopause women with prediabetes: a double-blind randomized controlled clinical trial.

BACKGROUND: Vitamin K, as a cofactor in the gamma carboxylation of certain glutamic acid (Gla) residues, has been related to glucose metabolism and insulin sensitivity. Osteocalcin, also known as bone γ-carboxyglutamic acid, increases ß-cell proliferation as well as insulin and adiponectin secretion, which improve glucose tolerance and insulin sensitivity. Thus, the purpose of the present study was to examine the possible role of adiponectin as a mediator of glucose homeostasis following phylloquinone supplementation in premonopause women with prediabetes. METHODS: Eighty two women were randomized to consume vitamin k1 supplement (n = 39) or placebo (n = 43) for four weeks. Participants in vitamin K1 treatment group received one pearl softgel capsule containing 1000 micrograms phylloquinone while the placebo group received one placebo capsules daily for four weeks. The Blood samples were collected at baseline and after a four-week intervention to quantify osteocalcin, adiponectin, leptin and relevant variables. RESULTS: Phylloquinone supplementation significantly increased serum adiponectin concentration (1.24 ± 1.90 compared with -0.27 ± 1.08 µg/ml), and did not alter total osteocalcin (0.50 ± 4.11 compared with 0.13 ± 1.85 ng/ml) and leptin (-0.29 ± 8.23 compared with -1.15 ± 5.25 ng/ml) compared with placebo. Adjustments for total osteocalcin and adiponectin using analysis of covariance (ANCOVA) did not affect the association of glycemic status with related variables. CONCLUSIONS: In conclusion our study demonstrated that phylloquinone supplementation improved glycemic status in premonopausal prediabetic women independent of adiponectin. TRIAL REGISTRATION: This trial was registered in Iranian Registry of Clinical Trials with ID number of IRCT2013120915724N1.