SERUM BETA-CAROTENE RESPONSE TO SUPPLEMENTATION WITH RAW CARROTS, CARROT JUICE OR PURIFIED BETA-CAROTENE IN HEALTHY NONSMOKING WOMEN

Epidemiological studies have shown that high intake of carotenoid-rich vegetables and fruits and high blood levels of beta-carotene are asso ciated with decreased risk of cancer. In western countries, carrot is the most important source of dietary beta-carotene. In the present stu dy, the serum response to chronic ingestion of beta-carotene from raw carrots, carrot juice and capsules containing purified beta-carotene w as studied. The subjects were 38 healthy, non-smoking female volunteer s, aged 20-53 years. They were instructed to consume low-carotenoid di ets for 10 days before starting the supplementation and throughout the study. According to food frequency questionnaires, the average habitu al intake of beta-carotene was 4.5 mg/day, whereas the low-carotenoid diet provided only 0.4 mg/day. After the 10-day depletion period, the average serum beta-carotene concentration fell to 53 % of the habitual level. The participants were assigned into three groups with similar mean serum beta-carotene concentrations. Each group was supplemented f or 6 weeks with approximately 12 mg of beta-carotene/day, either as ra w carrots (120 g/day), carrot juice (1 dl/day) or beta-carotene capsul es (2 capsules/day). The increase in serum beta-carotene level was det ermined after 3 and 6 weeks of supplementation. The mean serum beta-ca rotene concentration increased significantly in all test groups, the r esponse being greatest in the group receiving beta-carotene capsules. No difference in the serum response between carrot and carrot juice wa s detected. However, there was a wide variation in the individual resp onse of serum beta-carotene to supplementation, regardless of the sour ce. Variation was especially large - ranging from a lack of response t o over 8-fold increase in the serum beta-carotene concentration - in t he group receiving beta-carotene capsules. These data indicate that 1) serum response is lower after ingestion of natural beta-carotene than after ingestion of purified beta-carotene from capsules, and 2) equal intake of beta-carotene, whether from carrot, carrot juice or capsule s, elicits very different serum responses in different individuals.