适用于健康女性的维生素C最新推荐每日补充量(Rda)近日提出
WESTPORT, CT (Reuters Health) - The recommended daily allowance (RDA) of vitamin C for young healthy women should be increased from 75 mg per day to 90 mg per day, the same as the RDA for men, according to a report in the Proceedings of the National Academy of Sciences for August 14.
"In April of 2000 new dietary allowances for vitamin C were released by the Food and Nutrition Board of the National Academy of Sciences," Dr. Mark Levine from the National Institutes of Health, Bethesda, Maryland, noted in an interview with Reuters Health. "The data available were only for men, and the Food and Nutrition Board estimated women's RDA by using differences between men and women's body weight," he added.
The RDAs for vitamin C from the Food and Nutrition Board were 90 mg daily for men and 75 mg daily for women.
"The Food and Nutrition Board set very clear criteria as to how they calculated an RDA for men and we used the same criteria to calculate an RDA for women, and it came out to 90 mg of vitamin C per day, the same as for men," Dr. Levine said. In an inpatient depletion-repletion study, he and colleagues gave a wide range of vitamin C doses (30 mg to 2500 mg daily) to 15 healthy women 19 to 27 years of age.
Dr. Levine does not believe that the RDA of vitamin C should be derived from vitamin supplements. "Ninety milligrams of vitamin C can be easily achieved by eating five servings a day of a variety of fresh fruits and vegetables," he stressed. "We do not know if the benefits of vitamin C are from vitamin C alone, or in combination with other things in fruits and vegetables," he added.
There are no data on the RDA of vitamin C for older women, diabetics and smokers, Dr. Levine said. "Recommendations need to be made for public health even if we do not have complete data," he said. "While this study adds more information about vitamin C, it is not the complete story--more work needs to be done.", http://www.100md.com
"In April of 2000 new dietary allowances for vitamin C were released by the Food and Nutrition Board of the National Academy of Sciences," Dr. Mark Levine from the National Institutes of Health, Bethesda, Maryland, noted in an interview with Reuters Health. "The data available were only for men, and the Food and Nutrition Board estimated women's RDA by using differences between men and women's body weight," he added.
The RDAs for vitamin C from the Food and Nutrition Board were 90 mg daily for men and 75 mg daily for women.
"The Food and Nutrition Board set very clear criteria as to how they calculated an RDA for men and we used the same criteria to calculate an RDA for women, and it came out to 90 mg of vitamin C per day, the same as for men," Dr. Levine said. In an inpatient depletion-repletion study, he and colleagues gave a wide range of vitamin C doses (30 mg to 2500 mg daily) to 15 healthy women 19 to 27 years of age.
Dr. Levine does not believe that the RDA of vitamin C should be derived from vitamin supplements. "Ninety milligrams of vitamin C can be easily achieved by eating five servings a day of a variety of fresh fruits and vegetables," he stressed. "We do not know if the benefits of vitamin C are from vitamin C alone, or in combination with other things in fruits and vegetables," he added.
There are no data on the RDA of vitamin C for older women, diabetics and smokers, Dr. Levine said. "Recommendations need to be made for public health even if we do not have complete data," he said. "While this study adds more information about vitamin C, it is not the complete story--more work needs to be done.", http://www.100md.com
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