The relationship between vitamin K and T2DM: a systematic review and meta-analysis.

Background: Previous studies have shown the potential role of vitamin K supplementation in the prevention and treatment of many diseases. However, the effect of vitamin K supplementation on blood glucose remains controversial. The purpose of this study was to assess the effects of vitamin K supplementation on glycemia-related indicators, including Fasting Blood Sugar (FBS), Fasting Insulin (FINS) and Homeostasis Model Assessment of Insulin Resistance (HOMA-IR). The potential association between vitamin K and type 2 diabetes mellitus (T2DM) risk was also evaluated. Methods: Up to April 2023, Cochrane, PubMed, Web of Science, Medline and EMBASE databases were searched to assess the effects of vitamin K on blood glucose and the risk of developing T2DM. Results: A meta-analysis of seven studies (813 participants) found vitamin K supplementation significantly reduced FBS (SMD = -0.150 mg dl-1, 95% CI = -0.290, -0.010 mg dl-1) and HOMA-IR (SMD = -0.200, 95% CI = -0.330, -0.060), but not FINS. Five studies with a total of 105 798 participants were included in the meta-analysis of the association between vitamin K and T2DM. The results showed that vitamin K was associated with the reduced risk of developing T2DM (HR = 0.79, 95% CI [0.71-0.88], P < 0.001). Conclusion: The meta-analysis demonstrated that vitamin K supplementation had a significant effect on the regulation of FBS and HOMA-IR in the population. Moreover, vitamin K was associated with the reduced risk of developing T2DM. Considering some limitations found in this study, additional data from large clinical trials are needed.

Does vitamin D have a potential role in precocious puberty? A meta-analysis.

Background: Precocious puberty, one of the common pediatric endocrine system diseases, has been related to reduced adult height, adverse psychological outcomes and long-term health consequences. Previous findings have found that low levels of vitamin D appear to be associated with the characteristics of precocious puberty such as early menarche. However, the effect of vitamin D on precocious puberty remains controversial. Methods: The published literature was searched from PubMed, Web of Science, Cochrane Library, MEDLINE, EMBASE, CNKI, Wan Fang and VIP databases up to October 2022. A randomized effect model was used to perform a meta-analysis to evaluate differences in vitamin D concentration between precocious puberty subjects and normal subjects, the risk of precocious puberty in subjects with low vitamin D levels, and the effect of supplementation of vitamin D on subjects with precocious puberty on medication. Results: Our study found that precocious puberty subjects had lower serum vitamin D levels than the normal population (standardized mean difference (SMD) = -1.16 ng ml-1 and 95% confidence interval (CI) = -1.41 and -0.91 ng ml-1). Meanwhile, the lower level of vitamin D was associated with the risk of precocious puberty (odd ratio (OR) = 2.25 and 95% CI = 1.66 and 3.04). Moreover, compared with gonadotropin-releasing hormone analogue (GnRHa) intervention alone, subjects receiving GnRHa + vitamin D intervention had significantly lower luteinizing hormone (LH), follicle-stimulating hormone (FSH), and estradiol levels and bone age, and higher predicted adult height (PAH). Conclusions: Vitamin D may have a potential role in precocious puberty and more data from large clinical trials are needed to confirm the findings.

Effects of vitamin D supplementation on the regulation of blood lipid levels in prediabetic subjects: A meta-analysis.

This meta-analysis aimed to systematically investigate whether vitamin D supplementation reduces blood lipid-total cholesterol (TC), LDL cholesterol (LDL-C), HDL cholesterol (HDL-C), and triglyceride (TG)-levels in prediabetic individuals. Pubmed, Web of Science, Cochrane Library, Embase, CNKI, and WANFANG databases were searched for studies published before 13 February 2022 (including 13 February 2022). Five articles were included. The results showed that vitamin D intervention led to a significant reduction in TG compared with control or placebo treatment (-0.42 [-0.59, -0.25], P < 0.001). Subgroup analyses showed that this effect was particularly significant among the studies that included obese subjects (-0.46 [-0.65, -0.28], P < 0.001), the studies that also included men (not only women) (-0.56 [-0.78, -0.34], P < 0.001), and the studies with intervention durations longer than 1 year (-0.46 [-0.65, -0.28], P < 0.001). Both relatively low doses of 2,857 IU/day (-0.65 [-0.92, -0.38], P < 0.001) and relatively high doses of 8,571 IU/day (-0.28 [-0.54, -0.02] P = 0.04) of vitamin D supplementation reduced TG levels, and the effect was observed both in Northern Europe (-0.65 [-0.92, -0.38], P < 0.001) and Asian (-0.25 [-0.48, -0.03], P = 0.03) country subgroups. No significant effects on TC, HDL-C, and LDL-C were shown. In conclusion, vitamin D supplementation might beneficially affect TG levels in individuals with prediabetes. Particularly longer durations of treatment, more than 1 year, with doses that correct vitamin deficiency/insufficiency, can have a beneficial effect. This meta-analysis was registered at www.crd.york.ac.uk/prospero (CRD42020160780).

The association between carotenoids and subjects with overweight or obesity: a systematic review and meta-analysis.

BACKGROUND: Excess body weight, including overweight and obesity, is one of the major factors influencing human health, and plays an important role in the global burden of disease. Carotenoids serve as precursors of vitamin A-related retinoids, and are considered to have potential effects on many diseases. However, the influence of carotenoids on people with excess body weight is unclear. METHODS: This meta-analysis was conducted to assess the effects of carotenoids on overweight or obese subjects utilizing the available evidence. We searched PubMed, Medline, Cochrane Library, Web of Science and EMBASE databases up to September 2020. Random effects models were used to calculate the standard mean differences (SMDs) and odds ratios (ORs) with their 95% confidence intervals (95% CIs). RESULTS: A total of seven randomized controlled trials and eight observational studies met the inclusion criteria and contained 28 944 subjects and data on multiple carotenoid subgroups, including lycopene, astaxanthin, cryptoxanthin, α-carotene, and ß-carotene. In all included Randomized Controlled Trial (RCT), the intervention duration was 20 days at the shortest and 16 weeks at the longest, and the range of intervention doses was 1.2-60 mg d-1. Our study found that the insufficiency of serum carotenoids was a risk factor for overweight and obesity (OR = 1.73, 95% CI [1.57, 1.91], p < 0.001). Moreover, carotenoid supplementation was significantly associated with body weight reductions (SMD = -2.34 kg, 95% CI [-3.80, -0.87] kg, p < 0.001), body mass index decrease (BMI, SMD = -0.95 kg cm-2, 95% CI [-1.88, -0.01] kg cm-2, p < 0.001) and waist circumference losses (WC, SMD = -1.84 cm, 95% CI [-3.14, -0.54]cm, p < 0.001). CONCLUSION: In summary, the carotenoids show promising effects in overweight or obese subjects. Additional data from large clinical trials are needed.

A meta-analysis: Does vitamin D play a promising role in sleep disorders?

BACKGROUND: Sleep disorders, one of the most common problems in the general population, have been related to a series of harmful health consequences. Vitamin D appears to be associated with sleep disorders. However, the difference in vitamin D levels between sleep disorder subjects and people without a sleep disorder is unclear. Simultaneously, the influence of vitamin D replenishment on sleep disorders remains controversial. METHODS: PubMed, MEDLINE, Web of Science, and Cochrane Library were searched for literatures published until October 2019. Using a random effects model, a meta-analysis was conducted to calculate the standard mean difference to evaluate the difference in vitamin D concentrations between sleep disorder subjects and normal people and the efficacy of vitamin D supplementation on sleep disorders. RESULTS: Our study found that the serum vitamin D levels in the sleep disorder subjects were lower than that in the normal people (SMD = -0.75 ng/ml, 95% CI = -0.93, -0.57 ng/ml). Moreover, the Pittsburgh Sleep Quality Index (PSQI)in the subjects with vitamin D supplementation was lower than that in the controls (SMD = -0.45, 95% CI = -0.76, -0.13). CONCLUSIONS: Vitamin D could play a promising role in sleep disorders. More data are required to confirm the efficacy of vitamin D supplementation for improving sleep disorders.

The association between vitamin D levels and precocious puberty: a meta-analysis.

The objective of this short communication was the relationship between vitamin D and precocious puberty (PP). In this study, a comprehensive search of multiple databases was performed to identify studies focused on the association between vitamin D deficiency and PP. Studies that compared serum vitamin D levels between patients with PP and controls were selected for the systematic meta-analysis. The main outcome was the mean difference in serum vitamin D levels between PP and controls. Vitamin D-deficient subjects were more likely to develop PP. Our findings suggest that PP may be linked to vitamin D deficiency. Thus, providing supplements of vitamin D to PP patients may improve their nutritional status and prevent diseases. But, the amount of vitamin D required is uncertain, so it is important to be careful when taking vitamin D supplements.

Association Between Copper, Zinc, Iron, and Selenium Intakes and TC/HDL-C Ratio in US Adults.

The trace minerals zinc, copper, iron, and selenium are essential micronutrients, and because of their antioxidant activity, they are hypothesized to improve cardiovascular health. However, their associations with different risk levels for cardiovascular diseases are less clear. Data from the National Health and Nutrition Examination Survey 2007-2014 were used. In this study, the ratio of total cholesterol to high-density lipoprotein cholesterol (TC/HDL-C) was used as a risk marker for cardiovascular disease, and a ratio ≥ 5 was considered to indicate high risk. A total of 7597 adults (3673 men and 3924 women) were included, and 15.9% of the participants had a high risk of cardiovascular disease. Using quantile regression analysis, we found the negative correlation between zinc, copper, iron, and selenium intakes and TC/HDL-C. The effects of copper and zinc were enhanced with increasing quantiles of risk levels. In addition, the difference in the associations of the trace minerals was sex-dependent. The correlation between iron and cardiovascular risk in males was stronger than those in females, while that of copper was weaker than that in females. Moreover, a significant nonlinear relationship between selenium and the TC/HDL-C ratio was only found in females, and this relationship was U-shaped. Our findings suggest that among healthy adults in the US, zinc, copper, iron, and selenium intakes are inversely associated with cardiovascular disease risk, and the effect is enhanced with increasing quantiles of risk levels, with magnitudes differing by sex. Therefore, trace minerals may have the ability to prevent cardiovascular disease.

Associations between Omega-3 Fatty Acid Supplementation and Anti-Inflammatory Effects in Patients with Digestive System Cancer: A Meta-Analysis.

Purpose: Patients with digestive system cancer frequently over-express inflammatory cytokines after surgical operations or chemotherapy. Omega-3 fatty acids are key nutrients with numerous beneficial anti-inflammatory effects in cancer patients. The anti-inflammatory effect of supplementation with omega-3 fatty acids in patients with digestive system cancer requires further validation.Methods: The meta-analysis includes studies that compared the variations in inflammatory marker (interleukin-6, tumor necrosis factor-alpha, and C-reactive protein (IL-6, TNF-α, and CRP)) concentrations between patients with digestive system cancer who were supplemented with omega-3 fatty acids versus controls who were not supplemented with omega-3 fatty acids.Results: Our findings indicated that the variations in the IL-6 and CRP concentrations in patients with digestive system cancer did not differ between the supplementation groups and the controls. Statistically significant differences in the variations in the TNF-α concentrations were observed between the supplementation groups and the controls. However, there were no significant differences in the variations in the TNF-α concentrations according to the subgroup analysis.Conclusions: Omega-3 fatty acids may have an inhibitory effect on postoperative TNF-α elevation in patients with digestive system tumors, but additional supporting data require a large clinical trial.

Effects of probiotic supplementation on the regulation of blood lipid levels in overweight or obese subjects: a meta-analysis.

BACKGROUND: Obesity is a risk factor for many deadly diseases. Meanwhile, the prevalence of obesity has been continuously increasing in many countries. Probiotics are defined as live microorganisms that confer health benefits on hosts. Probiotic supplementation could reduce body weight, body mass index (BMI) and fat percentage. However, it is unclear whether supplementation with probiotics is beneficial to lower blood lipid levels for obese or overweight people. METHODS: In this study, a comprehensive search across multiple databases was performed to identify studies that focused on the effects of probiotics on blood lipid levels in overweight or obese subjects. The meta-analysis included studies that compared the variations in blood lipid (total cholesterol (TC), low density lipoprotein (LDL), high density lipoprotein (HDL) and triglyceride (TG)) concentrations between overweight and obese subjects who were supplemented with probiotics versus the controls who were not supplemented with probiotics. RESULTS: Our findings indicated that probiotic supplementation in obese or overweight people was associated with significantly larger reductions in TC and LDL levels compared to a lack of probiotic supplementation in the control subjects. However, there was no significant difference in the variations between HDL and TG concentrations. CONCLUSION: Probiotic supplementation reduced TC and LDL concentrations in obese or overweight people. Additional data from large clinical trials are required to confirm the efficacy and safety of probiotics in the regulation of blood lipid levels in obese or overweight people.

Association of multiple mineral and vitamin B group intake with blood glucose using quantile regression analysis: NHANES 2007-2014.

BACKGROUND: Hyperglycaemia and diabetes have become major public health problems worldwide. There is increasing evidence that minerals and the vitamin B group might play specific roles in hyperglycaemia and the pathogenesis and progression of diabetes or metabolic complications. OBJECTIVES: The main aim of this study is to investigate the effect of mineral and vitamin B group supplementation on the blood glucose levels of different populations. DESIGN: This was a cross-sectional study. Data from the National Health and Nutrition Examination Survey (NHANES) 2007-2014 were used in this study. A total of 8,322 participants (4,169 men and 4,153 women) were included in the study. Quantile regression (QR) was performed to identify the influence of mineral and vitamin B group intake on the level of fasting plasma glucose (FPG) in individuals in different quantiles of FPG. RESULTS: After adjusting for age, income, education, race, smoking, and alcohol consumption, FPG had a negative association with folic acid in individuals with normal or high FPG, with calcium in individuals with normal FPG, and with magnesium in males. FPG was negatively associated with folic acid and calcium in individuals with normal FPG, and magnesium in most of the quantiles for females. DISCUSSION: Hyperglycaemia and diabetes are currently becoming popular research topics. However, little is known about how the whole continuum of blood glucose is associated with commonly researched nutrient supplementation in terms of hyperglycaemia and diabetes. CONCLUSIONS: The intake of calcium, folic acid and magnesium was negatively associated with blood glucose levels in individuals in different quantiles of FPG. Appropriate prevention and treatment strategies should be developed for people with different blood glucose levels.