Research on vitamin C and diabetes treatment is inconclusive and varied. The human body does not produce its own vitamin C, which is required to make collagen, a structural component of blood vessels, tendons, ligaments, and bone. It is also critical for the function of neurotransmitters and is required for the synthesis of carnitine, essential for the transport of fat to mitochondria. There is also research showing that vitamin C is involved in the metabolism of cholesterol into bile acids. Additionally, vitamin C is a highly effective antioxidant leading to many studies of its disease prevention and treatment qualities.
Heart Disease, Vitamin C, and Diabetes
Heart disease is the leading cause of death amongst diabetics. Studies have shown that vitamin C therapy significantly alleviated vasodilation (constricted blood vessels) in individuals with coronary heart disease, angina pectoris, congestive heart failure, diabetes, high cholesterol, and high blood pressure. The First National Health and Nutritional Examination Survey found the risk of death from heart disease was 42% lower in men and 25% lower in women who consumed more than 50 mg/day of dietary vitamin C while taking vitamin C supplements.
Vitamin C and Diabetes
Due its antioxidant benefits and evidence that diabetes is a condition related to oxidative stress, there have been several long-term studies of vitamin C and diabetes. A 16-year study of 85,000 women, 2% of whom were diabetic, found that a vitamin C supplement of 400mg/day or more significantly reduced the risk of coronary heart disease. Conversely, a 15-year study of postmenopausal women found that women in the group taking 300 mg/day of vitamin C were at a higher risk of death from coronary heart disease and stroke than those who did not take supplements. Genetic research may be able to explain this anomaly. Analysis of haptoglobin genotype and antioxidant therapy found that vitamin C and E improved coronary athersclerosis in diabetic women with two copies of the haptoglobin 1 gene while worsening coronary athersclerosis in diabetic women with two copies of haptoglobin 2 gene. The complexity of the antioxidant system may also account for the differing results in the study. When antioxidants interact with free radicals, they become pro-oxidants that can require more antioxidants to detoxify them, a process that may be slower in diabetics. Dr. David R. Jacobs of the University of Minneapolis who conducted the 15-year study stated that while vitamin C in food can be balanced biochemically, supplements lack any balancing factors that can result in an antioxidant disturbance in the body.
The recommended daily allowance (RDA) of vitamin C for adult males is 90 mg/day and 75 mg/day for women.
