Antioxidant use in nutraceuticals.

The focus of this contribution is oxidation generated by oxygen and by all other reactive species, with an emphasis on reactive oxygen species. This study considers the different pathways that generate oxidative stress, which is a physiologic process that can become dangerous if becomes excessive and overcomes the reserve of antioxidants. Some of the most important methods to determine oxidative stress in plasma, both in humans and in experimental animals, are discussed; particular attention is given to the d-ROMs test, which detects the hydroperoxides in plasma and is a very simple and reliable method. The antioxidant hierarchy also is discussed to indicate the most powerful physiological antioxidant and those derived from food intake or supplementation. As every antioxidant also can be a pro-oxidant, indications are given about their use and how to avoid the administration of high dosages of a single antioxidant.