Effects of vitamins C and E and β-carotene on the risk of type 2 diabetes in women at high risk of cardiovascular disease: a randomized controlled trial

Song, Yiqing; Cook, Nancy R.; Chen, Albert; Denburgh, Martin Van; Manson, Jo Ann E.

doi:10.3945/ajcn.2009.27491

Cited by 139 publications

(103 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In the final step of selection, 38 articles were included to systematic review (58)(59)(60)(61)(62)(63)(64)(65)(66)(67)(68)(69), of which 5 articles were eligible to meta-analysis (58,59,61,63,65). The summary of eligible observational and RCT studies and their response to treatment are shown (Tables 1-4 …”

Section: Search Resultsmentioning

confidence: 99%

Influence of Ascorbic Acid Supplementation on Type 2 Diabetes Mellitus in Observational and Randomized Controlled Trials; A Systematic Review with Meta-Analysis

et al. 2015

View full text Add to dashboard Cite

-Purpose.There are controversial data regarding the beneficial effects of ascorbic acid (AA) supplementation in type 2 diabetes mellitus (T2DM). In this systematic review, we aimed to criticize the current relevant data from both observational and randomized controlled trials (RCTs). Methods. All observational and RCTs conducted to assess anti-hyperglycemic effects of AA in diabetics, published before January 2013, were included. To obtain all related studies Google Scholar, PubMed, Scopus, IranMedex, and Magiran web databases were searched. Exclusion criteria were animal studies, and studies conducted in Type 1 DM, children or pregnant women. Main outcome measures were fasting blood sugar (FBS), and glycated hemoglobin (HbA1c). According to degree of heterogeneity, fixed or random effect models were employed. Meta-analyses were done using Stats Direct software, version 3.0.97. The quality of included articles and publication bias were also assessed. Results. We selected 38 articles; 26 observational studies and 12 RCTs. Due to severe methodological heterogeneity in all observational studies and some of RCTs, we could pool data from only 5 RCTs in a meta-analysis. Single intake of AA versus placebo showed a significant effect on FBS; with the standardized mean difference (SMD): -20.59, 95% confidence intervals (95% CI): -40.77 to -0.4 (p= 0.04), but non-significant effect on HbA1c; SMD: -0.46, 95% CI: -1.75 to 0.84 (p= 0.4). Effect of other antioxidants with/without AA supplementation on FBSwere nonsignificant; SMD: -4.26 (p= 0.8), and SMD: -12.04 (p= 0.3), respectively. Also, their effect on HbA1c was non-significant; SMD: 0.53 (p= 0.11), and SMD: 0.28 (p= 0.34), respectively. Conclusions. Our study supports the positive effect of AA in reduction of FBS in diabetics, however, due to insufficient evidence ragarding long term safety of AA supplementation and limited number of RCTs, the long term use of this vitamin for its anti-diabetic properties cannot be strongly recommended.

show abstract

Section: Search Resultsmentioning

confidence: 99%

Influence of Ascorbic Acid Supplementation on Type 2 Diabetes Mellitus in Observational and Randomized Controlled Trials; A Systematic Review with Meta-Analysis

et al. 2015

View full text Add to dashboard Cite

show abstract

“…Therefore, we were unable to address whether the low serum levels and the coexistence of DM was a cause of the disease or the consequence, while the studies by Harding et al (20) show the evident causal relationship of vitamin C in the development of DM. However, it is controversial whether a high oral dose of vitamin C is beneficial in persons with DM (41)(42)(43)(44)(45) or preventing DM (46). Besides the protective effect of a high dose, it may be necessary to study whether low or deficient status of vitamin C leads or accelerates the development of DM.…”

Section: Discussionmentioning

confidence: 99%

Vitamin C Nutriture in Newly Diagnosed Diabetes

Shim

Paik

Shin

et al. 2010

J Nutr Sci Vitaminol

View full text Add to dashboard Cite

SummaryThis study was performed to investigate the relationship between serum Lascorbic acid, vitamin C intake, and diabetes in a nested case-control study. A cross-sectional survey of diet and health was conducted in 2,048 adults with an age of 30 y or older in Yonchon County, Korea. An oral glucose tolerance test was administered to all participants. One hundred cases of newly diagnosed diabetes were identified. Two healthy controls for each case matched with age, gender, drinking status, and smoking status were selected among the survey participants. L -Ascorbic acid levels were analyzed in fasting serum samples and one 24-h dietary recall was performed. Dietary vitamin C intake of persons with diabetes was 50.1 Ϯ 47.6 mg/d and that of controls was 55.1 Ϯ 41.1 mg/d. People with diabetes (22.3 Ϯ 16.8 mol/L) have lower serum ascorbic acid levels than their controls (26.3 Ϯ 17.0 mol/L) and the difference was significant by paired t -test ( p Ͻ 0.01). The association between diabetes and serum ascorbic acid level was still significant in non-smokers (24.2 Ϯ 17.8 mol/L for the diabetes group and 29.5 Ϯ 16.7 mol/L for the control group, p Ͻ 0.01) but not in smokers (19.4 Ϯ 15.7 mol/L for the diabetes group and 21.2 Ϯ 16.0 mol/L for the control group). Our results suggest that diabetes and smoking interactively affect serum ascorbic acid levels. Since this population had poor nutritional status of vitamin C, further investigation of association between serum ascorbic acid level and diabetes and smoking by the level of vitamin C consumption is warranted.

show abstract

“…The combination of vitamins C, E and b-carotene moderately reduced insulin resistance during an 8-week supplementation in overweight young adults (Vincent et al, 2009). However, controlled trials with high dosages of supplemental vitamin E and b-carotene have not shown decreased risk of type 2 diabetes (Liu et al, 1999(Liu et al, , 2006Lonn et al, 2002;Song et al, 2009). Also in the a-Tocopherol, b-Carotene Cancer Prevention (ATBC) Study there was no effect on diabetes risk by a-tocopherol and b-carotene supplementation (Kataja-Tuomola et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

Intake of antioxidants and risk of type 2 diabetes in a cohort of male smokers

et al. 2011

View full text Add to dashboard Cite

Background/Objectives: Oxidative stress may induce insulin resistance in peripheral tissues and impair insulin secretion from pancreatic b-cells. Antioxidants are suggested to decrease the risk of diabetes through reduction of oxidative stress. However, only a few studies exist on dietary antioxidants and the risk of type 2 diabetes. We investigated the association of dietary antioxidants with incident type 2 diabetes in the a-Tocopherol, b-Carotene Cancer Prevention Study cohort. Subject/Methods: The study cohort included 29 133 male smokers aged 50-69 years. During a median follow-up of 10.2 years 660 incident cases of diabetes were observed among the 25 505 men with a completed baseline food frequency questionnaire. Results: Dietary a-tocopherol, b-tocopherol and b-tocotrienol were positively associated with the risk of diabetes when adjusted for age and supplementation (relative risk (RR) 1.17 (95% confidence interval (CI) 0.91-1.51) P for trend 0.02; RR 1.31 (95% CI 1.02-1.68) P for trend 0.01; RR 1.28 (95% CI 1.00-1.63) P for trend 0.01, respectively), but the association disappeared after multivariate adjustment (RR 0.92 (95% CI 0.71-1.19) P for trend 0.97; RR 1.06 (95% CI 0.82-1.36) P for trend 0.48; RR 1.04 (95% CI 0.80-1.35) P for trend 0.46, respectively). Other tocopherols and tocotrienols as well as vitamin C, carotenoids, flavonols and flavones had no association with risk of diabetes. Conclusions: Dietary antioxidants were not associated with a decreased risk of incident diabetes in middle-aged male smokers.

show abstract

Effects of vitamins C and E and β-carotene on the risk of type 2 diabetes in women at high risk of cardiovascular disease: a randomized controlled trial

Abstract: Our randomized trial data showed no significant overall effects of vitamin C, vitamin E, and beta-carotene on risk of developing type 2 diabetes in women at high risk of CVD. This trial was registered at clinicaltrials.gov as NCT00000541.

Cited by 139 publications

References 40 publications

Influence of Ascorbic Acid Supplementation on Type 2 Diabetes Mellitus in Observational and Randomized Controlled Trials; A Systematic Review with Meta-Analysis

Influence of Ascorbic Acid Supplementation on Type 2 Diabetes Mellitus in Observational and Randomized Controlled Trials; A Systematic Review with Meta-Analysis

Vitamin C Nutriture in Newly Diagnosed Diabetes

Intake of antioxidants and risk of type 2 diabetes in a cohort of male smokers

Contact Info

Product

Resources

About