Nutritional Advice El Mondo
Objectives:
Randomised controlled trials (RCTs) have observed contrasting results on the effects of vitamin C on circulating biomarkers of glycaemic and insulin regulation. Therefore, this meta-analysis (systematic review) has been conducted.
Has vitamin C supplementation a favorable effect on circulating biomarkers of glycaemic and insulin regulation?
Study design:
This review article included 22 RCTs with 937 participants.
Results and conclusions:
The investigators found overall, vitamin C supplementation did not modify glucose, HbA1c and insulin concentrations.
The investigators found, however, subgroup analyses showed that vitamin C supplementation significantly reduced glucose concentrations with 0.44 mmol/L [95% CI = -0.81 to -0.07, p =0.01] in patients with type 2 diabetes and in interventions with a duration greater than 30 days [-0.53%, 95% CI = -0.79 to -0.10, p = 0.02].
The investigators found vitamin C administration had greater effects on fasting [-13.63 pmol/L, 95% CI = -22.73 to -4.54, p 0.01] compared to postprandial insulin concentration. However, meta-regression analyses showed that age was a modifier of the effect of vitamin C on insulin concentration.
The investigators found the effect size of vitamin C supplementation was associated with baseline BMI and plasma glucose levels and with the duration of the intervention.
The investigators concluded vitamin C supplementation has greater reduction in glucose concentrations in patients with type 2 diabetes, older individuals and with more prolonged supplementation (greater than 30 days). Personalized interventions with vitamin C may represent a feasible future strategy to enhance benefits and efficacy of interventions. Nevertheless, results need to be interpreted cautiously due to limitations in the primary studies.
Original title:
Effects of vitamin C supplementation on glycaemic control: a systematic review and meta-analysis of randomised controlled trials by Ashor AW, Werner AD, […], Siervo M.
Link:
https://www.ncbi.nlm.nih.gov/pubmed/28294172
Additional information of El Mondo:
Find more information/studies on vitamin C and diabetes right here.