Vitamin K, as a cofactor in the gamma carboxylation of certain glutamic acid (Gla) residues, has been related to glucose metabolism and insulin sensitivity

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.

Background: In this meta-analysis, findings from recent studies on the preventive properties of anthocyanins (ACN) against cardiovascular disease are summarized. Methods: MEDLINE, PubMed, Embase, Cochrane Library, and Google Scholar were searched and 2512 studies were found in a preliminary search. After screening of titles and abstracts, 47 studies met the inclusion criteria (randomized clinical trial design and sufficient data of outcomes). Studies were excluded based on the following criteria: incomplete data; obscurely reported outcomes, or lack of control groups; and animal studies. Results: The results showed that intervention with ACNs resulted in a significant decrease in body mass index ((MD),− 0.21; 95% CI, − 0.38, − 0.04; P < 0.001) and body fat mass (MD: − 0.3%, 95% CI − 0.42 to − 0.18%, p < 0.001). Pooled data comparing ACN with control showed statistically significant effect on fasting blood sugar and HbA1c. However, the reductions were significantly more in the subjects with type 2 diabetes and in those who used ACN as supplement/extract. The subgroup analysis test showed that there was a significant effect of ACN on triglyceride concentrations, total cholesterol, LDL-C and HDL-C concentrations in all subgroups of participants (with vs. without dyslipidemia at baseline) and intervention type (supplement/extract vs. food). However, we did not observe any significant effect on apo A and apo B concentrations. Conclusions: ACN intake in the forms of natural foods and supplements can induce healthy changes in body fat mass, glycemic and lipidemic status and these effects are more prominent in the subjects with above-normal values. This meta-analysis was registered at http://www.crd.york.ac.uk/Prospero (Registration no. CRD42021286466).

Current household food waste (HFW) reduction plans usually focus on raising consumer awareness, which is essential but insufficient because HFW is predominantly attributed to unconscious behavioral factors that vary across consumer groups. Therefore, identifying such factors is crucial for predicting HFW levels and establishing effective plans. This study explored the role of dietary patterns (DP) and socioeconomic status (SES) as predictors of HBW using linear and non-linear regression models. Questionnaire interviews were performed in 419 households in Shiraz during 2019. A multilayer sampling procedure including stratification, clustering, and systematic sampling was used. Three main DPs, i.e., unhealthy, Mediterranean, and traditional, were identified using a food frequency questionnaire. Results indicated that a one-unit rise in the household’s unhealthy DP score was associated with an average increase in HBW of 0.40%. Similarly, a one-unit increase in the unhealthy DP score and the SES score increased the relative likelihood of bread waste occurrence by 25.6% and 14.5%, respectively. The comparison of findings revealed inconsistencies in HFW data, and therefore the necessity of studying HFW links to factors such as diet and SES. Further investigations that explore HFW associations with household characteristics and behavioral factors will help establish contextual and effective consumer-focused plans.

Findings on the association of dietary intake and tissue biomarkers of linoleic acid (LA) with the risk of prostate cancer are conflicting. Also, no meta-analysis summarized available findings in this regard. Therefore, the current systematic review and dose-response meta-analysis were done to summarize the findings of prospective cohort studies that assessed dietary intake and tissue biomarkers of LA in relation to prostate cancer risk in adults. We conducted a systematic search using online databases, including PubMed, Scopus, and ISI Web of Science, to identify eligible articles published up to January 2023. We included prospective cohort studies that examined the associations of dietary intake and tissue biomarkers of LA with the risk of prostate cancer (total, advanced, and fatal prostate cancer). Summary relative risks (RR) and 95% confidence intervals (CI) were calculated for the highest versus lowest intakes/tissue levels of LA using a fixed-effects model. Also, linear and non-linear dose-response analyses were conducted. In total, 15 prospective cohort studies were included. These studies recruited a total sample size of 511,622 participants with an age range of ≥18 years. During the follow-up periods ranging from 5 to 21 years, 39,993 cases of prostate cancer, 5,929 cases of advanced prostate cancer, and 1,661 cases of fatal prostate cancer were detected. In the meta-analysis, we found that higher tissue levels of LA were associated with a reduced risk of prostate cancer (RR: 0.86, 95% CI: 0.77–0.96) so that in the dose-response analysis, each 5% increase in levels of LA was associated with a 14% lower risk of prostate cancer. Such a significant association was not seen for advanced prostate cancer (RR: 0.86, 95% CI: 0.65–1.13). Also, we found no significant association between dietary intake of LA and risk of total (RR:1.00, 95% CI: 0.97–1.04), advanced (RR: 0.98, 95% CI: 0.90–1.07), and fatal prostate cancer (RR: 0.97, 95% CI: 0.83–1.13). Our findings support the protective association between tissue levels of LA and the risk of prostate cancer in men.