Antioxidant supplements are compounds obtained either
by extraction from natural foods or by chemical synthesis.
Of course, they do not have the same composition
as natural antioxidants in foods. Therefore, opinions are
divided over whether or not antioxidant supplements offer
the same health benefits as antioxidants in foods (6, 57-59).
Even if antioxidant supplementation is receiving enthusiastic
debate and is increasingly adopted in many industrial
countries, supporting evidence is still ambiguous (5-59).
Although many epidemiological data suggest that antioxidants
may have a beneficial effect on many chronic diseases,
the systematic use of supplements is hindered by several
factors: the lack of prospective and controlled studies,
the long-term effects and the dosages necessary for each
type of diseases. Also, antioxidant supplements can act as
pro-oxidants e.g. as oxidative stress inducers if they are
consumed at levels significantly above the recommended
dietary intakes (RDI). Like conventional medicines, dietary
supplements may cause side effects, or interaction
with another medication or supplement, that may make the
health worse. However, dietary supplements can become
necessary and useful in some particular situations, such
as soldiers in front, sailors in ships, patients with gastrointestinal
disorders, or people with low incomes, e.g. people
who cannot afford a variety of vegetables, fruits, and