NEW YORK, NY. Chemotherapy is associated with a significant increase in free radical activity, which, in turn, can overwhelm the body's natural antioxidant defenses. Researchers at Columbia University have just completed a study to determine if body stores of the common dietary antioxidants, vitamin A, vitamin C, vitamin E, and the carotenoids, decrease during chemotherapy and if higher intakes of these antioxidants result in fewer side effects from the therapy.

The study involved 100 children and adolescents (1-18 years of age) with acute lymphoblastic leukemia. Dietary intakes and blood plasma concentrations of antioxidants were measured at diagnosis and after 3 and 6 months of chemotherapy at which times the researchers also noted any side effects of the therapy. Among their most important findings are:

• Antioxidant intake at diagnosis and throughout the 6-month study period was well below the RDA for a large percentage of the children. At least 88% of the children reported intakes below the RDA for at least one antioxidant. Sixty-six percent were deficient in vitamin E intake, 59% deficient in beta-carotene intake, and 29% deficient in vitamin-A. Vitamin C intake was considered adequate at 70-100 mg/day. (Editor's note: Although the vitamin C intake is above the RDA, numerous studies have shown that it would be totally inadequate to provide any meaningful antioxidant protection).

• Almost half the children had an inadequate level of vitamin C in their blood plasma despite a supposedly adequate intake. A significant decrease in plasma vitamin E level was observed over the 6-month treatment period, while total carotenoid and vitamin A levels increased over the period.

• At the 6-month stage greater intakes of vitamin-C were found to be significantly associated with a lower risk of liver toxicity, fewer days spent in hospital, and fewer delays in the administration of scheduled chemotherapy because the children were too sick to undergo further treatment. Unfortunately, the plasma concentrations of vitamin C tended to decrease as treatment progressed. Higher average intakes of beta- carotene and total carotenoids were also associated with a lower incidence of chemotherapy-related toxicity.

• A greater intake of vitamin-E at the 3-month checkpoint was associated with a lower incidence of infection.

The researchers conclude that, "it would be prudent for children with acute lymphoblastic leukemia to receive nutritional counseling to ensure that they are meeting their needs for antioxidant nutrients".
Kennedy, DD, et al. Low antioxidant vitamin intakes are associated with increases in adverse effects of chemotherapy in children with acute lymphoblastic leukemia. American Journal of Clinical Nutrition, Vol. 79, June 2004, pp. 1029- 36

Editor's comment: This study clearly shows that an adequate antioxidant intake is vitally important in order to reduce the side effects from chemotherapy. Although the study involved children, there is no reason to assume that the findings would not apply equally well to adults. Although this particular group of researchers does not advocate antioxidant supplementation at this time, they do recommend that the potential benefits of supplementation be investigated in a future study.