Dietary lipid level and the availability of beta-carotene of Dunaliella-bardawil in rats.

High plasma and tissue levels of beta-carotene have been implicated to be inversely related to the incidence of some types of cancer. Previous studies indicated that the availability of the natural beta-carotene isomer mixture of Dunaliella bardawil was severalfold higher than that of synthetic all-trans beta-carotene. This study illustrated that this higher availability, as expressed by hepatic and plasma beta-carotene, can be further enhanced by increased dietary lipid level. For 12 days, weanling male and female rats were fed diets containing either 0.1% all-trans beta-carotene or spray-dried Dunaliella bardawil having an equal level of the beta-carotene isomer mixture. The diets contained 5 or 15% soybean oil. The rise in dietary fat resulted in a marked increase in plasma and liver beta-carotene, with the Dunaliella isomer mixture being more effective. Higher levels were found in female than in male animals. These findings may be relevant when a high dose of beta-carotene is considered as a potential anticancer agent.