Absorption, by humans, of beta-carotene from fortified soybean oil added to rice: effect of heat treatment.

OBJECTIVE

This study was carried out to evaluate the absorption of beta-carotene in humans when rice is prepared with refined cooking soybean oil fortified with beta-carotene and to assess the effect of heat treatment on its bioavailability.

METHODS

Sixteen healthy adults subjects participated in two experimental trials. Studies were carried out during two experimental periods of 11 days with a 12-day interval between them. Beta carotene was added to the soybean cooking oil and rice was cooked with it or it was added to the rice after cooking. Experimental diets included these two kinds of rice during the first day and fasting blood samples were collected on different days. All of the test diets were low in carotenoids. Plasma carotenoids were measured by HPLC method. beta-carotene absorption was calculated through postabsorptive peak rise in plasma beta-carotene and the total area under the absorption curve was determined by the trapezoidal method for the 11-day period.

RESULTS

Absorption of carotene from heated or unheated fortified soybean oil were similar. Peak plasma carotene rise was different in men and women, p < 0.05 (0.66 +/- 0.097 vs. 1.04 +/- 0.117 mumol/l, respectively). Plasma alpha-carotene and retinol showed no variation.

CONCLUSIONS

Results demonstrate that beta-carotene added to soybean oil used in the preparation of rice is absorbed, heated or not, and could be a practical source of provitamin A. Developing countries looking for strategies to increase vitamin A intake could use fortification of vegetable oils with synthetic beta-carotene as a simple method.