Study Links Vitamin C with Improved Blood Glucose Levels

Vitamin C supplementation is associated with improved blood glucose levels.

New research suggests that vitamin C supplementation is associated with improved blood glucose levels in people with type 2 diabetes.

A small Australian study, published in 2019 in the journal, Diabetes, Obesity and Metabolism, reports that people with type 2 diabetes who took a vitamin C tablet two times a day reduced their blood glucose spikes after meals by 36%.

According to this research, subjects who took the vitamin C supplements spent almost three hours less per day with high blood glucose levels. A total of 31 participants took part in the study, comprising of 26 men and five women, all of whom had type 2 diabetes.

Subjects were divided into two groups. One group was given a placebo that looked exactly like the vitamin C supplement, while the second group was given two capsules of 500mg doses of vitamin C daily. Both groups ate standardized meals and were monitored with continuous glucose monitors over a four-month period.  After 4 months the participants stopped taking their capsules for at least 1 month to allow any residual supplement to leave their bodies. Then each group was switched to the other type of capsule for another 4 months.

For the 27 participants who completed the study, post-meal blood sugar levels were significantly lower following 4 months of vitamin C supplementation compared with 4 months of placebo treatment. After taking vitamin C supplements, participants also had fewer hours per day with hyperglycemia (high blood sugar levels) or post-meal hyperglycemia and had lower blood pressure.

Scientists reported that participants had a significant 36% drop in blood sugar spike after meals. “This is extremely positive news as hyperglycemia is a risk factor for cardiovascular disease in people living with type 2 diabetes,” said associate professor Glenn Wadley, who led the study.

Wadley went on to say, “For people living with type 2 diabetes, vitamin C could be a potentially cheap, convenient and effective additional therapy, used in addition to their usual anti-diabetic treatments.”

Further research is needed, but this is positive news for the millions of people living with type 2 diabetes. Vitamin C supplementation is readily available and is worth discussing with your doctor if you suffer with type 2 diabetes.


Mason SA, Rasmussen B, van Loon LJC, et al. Ascorbic acid supplementation improves postprandial glycaemic control and blood pressure in individuals with type 2 diabetes: Findings of a randomized cross-over trial. Diabetes Obes Metab 2019;l21:674-82.

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