July 29/Health & Medicine Week -- "It has been hypothesized that organically grown vegetables are healthier than conventionally produced ones due to a higher content of phytochemicals. However, few data from controlled human studies exist," researchers in Karlsruhe, Germany, report.

"The aim of the present study was to compare the carotenoid content and antioxidant capacity of organically and conventionally produced carrots under defined conditions. Furthermore, a human intervention study was conducted to compare bioavailability, plasma antioxidant capacity, endogenous DNA strand breaks and immune parameters in healthy men ingesting carrots from different agricultural systems. Thirty-six volunteers consumed either organically or conventionally produced blanched carrots (200g/d; 2 weeks) or no carrots in a double-blind, randomised intervention study. No statistically significant differences were observed in the total carotenoid contents (121 (SD 7) mu g/g organic v. 116 (SD 13) mu g/g conventional) and the antioxidant capacities (0.43 (SD 0.08) mu mol Trolox equivalents/g organic v. 0.32 (SD 0.07) mu mol Trolox equivalents/g conventional) of the carrots administered to the volunteers. Intake of organically or conventionally produced carrots significantly increased (P <0.001) plasma alpha- and beta-carotene concentrations in both intervention groups without differences in plasma carotenoid concentrations. Consumption of carrots did not lead to significant changes in the plasma antioxidant status, endogenous DNA strand breaks and parameters of the immune system in all groups," wrote B.A. Stracke and colleagues.

The researchers concluded, "Therefore, these results indicate that the agricultural system has neither an effect on the carotenoid content, the antioxidant capacity of carrots, nor on the bioavailability of carotenoids and on antioxidant, antigenotoxic and immunological effects as assessed in a human intervention study."

Stracke and colleagues published their study in British Journal of Nutrition ("Bioavailability and Nutritional Effects of Carotenoids from Organically and Conventionally Produced Carrots in Healthy Men." British Journal of Nutrition, 2009;101(11):1664-1672).

For additional information, contact B. Watzl, Max Rubner Institute, Fed Research Institute Nutrition & Food, Institute Physiol & Biochemistry Nutrition, Haid & Neu Str 9, D-76131 Karlsruhe, Germany.

From the August 3, 2009, Prepared Foods E-dition