The Food and Nutrition Board of the National Academies of Science has released the latest DRI series on dietary antioxidants including; vitamin C, vitamin E, selenium, and carotenoids. In recent years, researchers have focused on the possible role that dietary antioxidants play in promoting and maintaining health. Dietary antioxidants are nutrients that help protect cells from the normal – but damaging – physiological process known as "oxidative stress." Although a large number of studies reveal a link between a diet rich in foods containing antioxidants, such as fruits and vegetables, and a lower incidence of certain chronic diseases, the report states insufficient evidence exists to support claims that taking megadoses of dietary antioxidants can prevent chronic diseases. The report does call for increases in daily intakes of vitamins C and E to exploit their role in maintaining good heath, and recommends an even larger amount of vitamin C for smokers. For the first time, the report also sets an upper limit on daily consumption of selenium, and vitamins C and E to reduce the risk of adverse side effects from over use.

The recommended daily intake levels for vitamin C were increased to 75 milligrams per day for adult women and 90 milligrams per day for adult men. Because smoking may increase biological processes that damage cells and deplete vitamin C, an additional 35 milligrams per day are recommended for people who smoke. The upper intake level for vitamin C, from both food and supplements, was set at 2,000 milligrams per day for adults. Intakes above this amount may cause diarrhea.

The recommended daily intake levels for vitamin E were also increased to 15 milligrams per day for both adult men and women. This is equivalent to 22 International Units (IU) of natural-source vitamin E or 33 IUs of synthetic vitamin E. The upper intake level, based only on vitamin E supplements, was set at 1,000 milligrams per day for adults. This amount is equivalent to roughly 1,500 IU of "natural source" vitamin E or 1,100 IU of synthetic vitamin E. Intakes above this amount may increase the risk of hemorrhagic damage because vitamin E can act as an anticoagulant.

The recommended daily intake levels for selenium were set at 55 micrograms per day for both men and women. The upper intake level for selenium, from both food and supplements, was set at 400 micrograms per day. Intakes above this amount may cause selenosis, a toxic reaction marked by hair loss and nail sloughing.

In laboratory studies, carotenoids have been shown to act as antioxidants; however, the results have not been consistently duplicated in humans. In addition, adverse effects in humans have been reported with over consumption of carotenoids. For these reasons, the report does not recommend a daily intake level or an upper intake level for consumption of carotenoids. The report recommends that people should use caution before taking carotenoids in high doses.