US government researchers suggest that the recommended daily allowance (RDA) of vitamin C for healthy young women should be increased from 75 milligrams (mg) to 90 mg. In April 2000, the Food and Nutrition Board issued a 75-mg recommendation, based on the results of studies in men. Now that data for women are available, 90 milligrams is a better recommendation, Dr. Mark Levine of the National Institutes of Health, Bethesda, Maryland, and colleagues report. Levine and colleagues studied vitamin C levels in blood samples of 15 healthy women who volunteered to live in a hospital for 6 months. There, the women ate carefully controlled diets that contained no vitamin C. The volunteers were given vitamin C supplements ranging from 30 mg to 2,500 mg per day. Comparing vitamin C blood levels with criteria for ideal intake, researchers arrived at the 90-mg recommendation. "90mg daily can easily be achieved by eating five varied servings of fresh fruits and vegetables, and this amount of fruits and vegetables has health benefits," Dr. Levine added. Vitamin C sources include citrus fruits, potatoes, strawberries, broccoli and leafy green vegetables. "This is a reasonable and sound study," Dr. Jeffrey Blumberg of Tufts University in Boston, Massachusetts, told Reuters Health. But, he noted that the women in the study did not smoke, drink alcohol or take any medications, all of which could impact levels of vitamin C in the body.
