Vitamin C levels are reduced in persons with type 2 diabetes. Researchers believe that diminished tissue levels of vitamin C exacerbate blood vessel dysfunction and contribute to arteriosclerosis.
In a study, thirty people aged 45 to 70 years, with type 2 diabetes were given either 500 mg of vitamin C daily or a placebo. The people given the vitamin C had improved arterial and aortic stiffness. Also, their avarice blood pressure readings improved: systolic from 142.1 to 132.3 mmHg and diastolic from 83.9 to 79.5 mmHg.
Mullen and others. "Ascorbic Acid Reduces Blood Pressure and Arterial Stiffness in Type 2 Diabetes." Hypertension. 2002;40:804-809.