Effects of vitamin C supplementation on glycaemic control: a systematic review and meta-analysis of randomised controlled trials

2017 ◽  
Vol 71 (12) ◽  
pp. 1371-1380 ◽  
Author(s):  
A W Ashor ◽  
A D Werner ◽  
J Lara ◽  
N D Willis ◽  
J C Mathers ◽  
...  
2017 ◽  
Vol 6 ◽  
Author(s):  
Mary M. Murphy ◽  
Erin C. Barrett ◽  
Kara A. Bresnahan ◽  
Leila M. Barraj

AbstractStudies on the effects of consuming 100 % fruit juice on measures of glycaemic control are conflicting. The purpose of the present study was to systematically review and quantitatively summarise results from randomised controlled trials (RCT) examining effects of 100 % fruit juice on glucose–insulin homeostasis. Eligible studies were identified from a systematic review of PubMed and EMBASE and hand searches of reference lists from reviews and relevant papers. Using data from eighteen RCT, meta-analyses evaluated the mean difference in fasting blood glucose (sixteen studies), fasting blood insulin (eleven studies), the homeostatic model assessment of insulin resistance (HOMA-IR; seven studies) and glycosylated Hb (HbA1c; three studies) between the 100 % fruit juice intervention and control groups using a random-effects model. Compared with the control group, 100 % fruit juice had no significant effect on fasting blood glucose (−0·13 (95 % CI −0·28, 0·01) mmol/l; P = 0·07), fasting blood insulin (−0·24 (95 % CI −3·54, 3·05) pmol/l; P = 0·89), HOMA-IR (−0·22 (95 % CI −0·50, 0·06); P = 0·13) or HbA1c (−0·001 (95 % CI −0·38, 0·38) %; P = 0·28). Results from stratified analyses and univariate meta-regressions also largely showed no significant associations between 100 % fruit juice and the measures of glucose control. Overall, findings from this meta-analysis of RCT suggest a neutral effect of 100 % fruit juice on glycaemic control. These findings are consistent with findings from some observational studies suggesting that consumption of 100 % fruit juice is not associated with increased risk of diabetes.


BMJ Open ◽  
2012 ◽  
Vol 2 (6) ◽  
pp. e001803 ◽  
Author(s):  
Morten Hansen ◽  
David Peick Sonne ◽  
Kristian Hallundbæk Mikkelsen ◽  
Lise Lotte Gluud ◽  
Tina Vilsbøll ◽  
...  

2015 ◽  
Vol 33 (4) ◽  
pp. 254-261 ◽  
Author(s):  
Qianyun Chai ◽  
Yutong Fei ◽  
Huijuan Cao ◽  
Congcong Wang ◽  
Jinzhou Tian ◽  
...  

Background Melasma is a common facial skin disorder seen in women. Manual acupuncture (MA) is widely used alone or in combination with conventional treatments for melasma in China. Objectives To assess the effectiveness and safety of MA for melasma, and explore the range of treatments applied. Methods Six databases were searched systematically for randomised controlled trials (RCTs) on acupuncture for melasma in women up to November 2014. RevMan software was used for data analysis. The Cochrane tool of Risk of Bias was used to assess the methodological quality of the RCTs. Results Eight RCTs involving 587 women were included. Seven studies used the encircling needling method, four studies used the quick needling method and four studies used intensive needle manipulations. Five studies provided individualised acupuncture treatments. Points used with highest frequency were SP6, ST36 and SP10. MA was compared with oral tranexamic acid, vitamin C and E, vitamin C and tamoxifen, topical 20% azelaic acid, hydroquinone, vitamin A and no treatment. Studies were too heterogeneous to conduct a meta-analysis. For global outcome measures, seven trials showed that MA groups were significantly better than the conventional treatments either with a better cure rate or with a better combined cure rate and markedly effective rate, and one trial did not (MA vs vitamin A). No acupuncture-related adverse events were reported. Conclusions MA appeared to be beneficial and safe for women with melasma, but insufficient evidence was found to reach conclusions. The encircling needling method, the quick needling method, intensive needle manipulations and individualised points’ selection were widely used. Well-designed trials are required. Trial Registration Number PROSPERO Systematic review registration: CRD42013006396.


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