The contribution of β-carotene to vitamin A supply of humans.

Populations that administer highly restrictive diets using a strong dietary regime, excluding certain types of food, might be at risk of vitamin A insufficiency, even in developed countries. Thus, provitamin A carotenoids from plants represent an additional major dietary source of vitamin A for most of the world's population. Our aim was to estimate the contribution of β-carotene to vitamin A supply in industrialized countries using available data from the literature. A total of 11 studies from 8 countries were used, representing data of 121,256 participants. Intakes of total vitamin A, provitamin A carotenoids, including β-carotene were retrieved and used to calculate the retinol activity equivalents (RAE) utilizing current conversion factors. Mean total daily dietary intake of RAE was 1083±175. The mean β-carotene intake was 3.9 mg/day. Preformed vitamin A accounts for nearly 65% of total vitamin A intake, carotenoids make up 35%. No statistical differences between men and women in total intake of retinol were observed. We conclude that a safe vitamin A intake in general cannot be reached by consuming only one component (vitamin A or β-carotene) alone, even in Western countries where animal products are commonly available.