Vitamin C consumption linked to reducing post-prandial glycemic response

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A randomized controlled trial investigates the effect of Vitamin C in postprandial glycaemic control and blood pressure.

Vitamin C is a potent free radical scavenging antioxidant with various health and clinical benefits. Oxidative stress has been implicated in the pathogenesis of diabetes accounting for insulin resistance and hyperglycemia induced complications in recent studies. Furthermore, increased oxidative stress1 and reduced basal vitamin C levels2 have been found in diabetics.

In a recent study by Mason et al., the effect of vitamin C supplementation (500 mg twice daily) for 4 months on post prandial glycemic response and blood pressure was investigated. The study revealed a statistically significant, 36% reduction in daily postprandial blood glucose level, in addition to decreased mean post prandial glycemic response when compared to placebo. As post prandial hyperglycemia in type 2 diabetics is an independent risk factor for cardiovascular diseases and cardiovascular events, these results have positive clinical implications.

Based on prior findings, Mason et al. speculated that the reduction in post prandial glycemic response could be attributed to an accentuation of insulin-mediated peripheral glucose disposal. In addition, increase in skeletal muscle vitamin C concentration was observed along with decrease in muscle oxidative stress during hyperinsulinemia. These findings are suggestive of enhanced antioxidative effect on muscle insulin sensitivity.

Due to the favorable effects of vitamin C found in the study on post prandial glycemic response, blood pressure and oxidative stress, the authors suggest that increasing vitamin C plasma concentration in type 2 diabetics with reduced vitamin C levels could be an effective adjunct strategy to anti-diabetic medication. Similarly, vitamin C supplementation as an adjunct to anti-diabetic medication showed favorable results with no adverse effects in another study3. Therefore, vitamin C could be a suitable and cost effective adjunct for the management of hyperglycemia and blood pressure in type 2 diabetics.

Mason S, Rasmussen B, van Loon L, Salmon J, Wadley G. Ascorbic acid supplementation improves postprandial glycaemic control and blood pressure in individuals with type 2 diabetes: Findings of a randomized cross-over trial. Diabetes, Obesity and Metabolism. 2019;21(3):674-682.

References

  1. Ting HH, Timimi FK, Boles KS, Creager SHJ, Gans P, Creager MA. Vitamin C improves endothelium dependent vasodilation in patients with non-insulin dependent diabetes mellitus. J Clin Invest 1996; 97 : 22-8. 3.
  2. Chen MS, Hutchinson ML, Pecoraro RE, Lee WY, Labbe RF. Hyperglycemic-induced intracellular depletion of ascorbic acid content in adults with insulin-dependent diabetes mellitus consuming adequate dietary vitamin C. Metabolism 1991; 40 : 146-9.
  3. Dakhale G, Chaudhari H, Shrivastava M. Supplementation of Vitamin C Reduces Blood Glucose and Improves Glycosylated Hemoglobin in Type 2 Diabetes Mellitus: A Randomized, Double-Blind Study. Advances in Pharmacological Sciences. 2011;2011:1-5.