"We have shown that exogenously added creatine, at concentrations comparable to those attainable in plasma upon oral supplementation, exerts direct antioxidant activity in cultured mammalian cells exposed to various oxidizing agents," wrote lead author Piero Sestili from the Università degli Studi di Urbino, Italy.
Creatine, which occurs naturally in foods like fish and red meat, is banned in some countries because of studies showing a possible link between long-term supplementation and increased cancer risk. It is not banned by the International Olympic Committee, which classifies it as food.
The new study, published in the journal Free Radical Biology and Medicine (Vol. 40, pp. 837-849), is said to be the first to look at the effect of creatine on human cell cultures exposed to a range of oxidising agents, including hydrogen peroxide and tert-butylhydroperoxide.
The researchers found that addition of the creatine to the cell cultures boosted the percentage survival of cells by more than 20 per cent compared to cells exposed to oxidising agents without creatine.
"Our data suggests that creatine would act via direct scavenging of the free radical species generated by the oxidants within the cells," said Sestili.
The researchers note that certain organs in the body, such as the heart and brain, normally have fairly high levels of creatine, and that these organs are sensitive to oxidative stress. Previous studies have suggested creatine supplementation to be beneficial in the prevention of various cardiovascular and neurological diseases.
"Nutritional intervention preventive strategies are mainly based on an adequate intake of antioxidant micronutrients (vitamins, trace elements, polyphenols) but, beyond micronutrients, it would be interesting to consider a well bioavailable nutrient such as creatine as an antioxidant. Clinical studies in this direction should be encouraged," concluded Sestili.
Concerns about the possible cancer risk of creatine supplements has slowed the market recently, which grew by only 4.2 per cent in 2004, a sharp contrast with the 50 per cent growth rates seen in the late 1990's.