Beta-carotene Absorption and Bioconversion to Vitamin A From Biofortified Cassava Gari

Vitamin A deficiency (VAD) is a major public health problem in most of the developing world, especially Southern Asia and Sub-Saharan Africa. The primary issue in vitamin A deficient populations is the low vitamin A content of the diet. Beta-carotene is the most abundant provitamin A carotenoid in nature and in human tissues. Increasing the concentrations of bioavailable vitamin A-forming carotenoids in staple foods by selective breeding is a good strategy for improving vitamin A status. Cassava, bred to contain high amounts of vitamin A-forming carotenoids is one such food, since it is a staple crop in Africa and parts of South America. A popular cassava product Africa is gari, which is fermented, dewatered, milled, and roasted so that it can be used for porridges and in baking. However, the effect of feeding biofortified gari meals on carotenoid and vitamin A concentrations in the body is not known. A common practice is to add red palm oil to typical white cassava gari. Red palm oil is a very rich source of alpha-carotene and beta-carotene, in highly bioavailable forms. Unfortunately, little is known of the bioconversion of red palm oil cassava mixture carotenoids to vitamin A.

The primary purpose of this study is to determine the effect of consuming gari that is made from biofortified cassava on carotenoid and vitamin A concentrations. The investigators will compare carotenoid and vitamin A concentrations in individuals fed biofortified gari to the same individuals fed gari made from ordinary cassava. The investigators hypothesis is that the biofortified gari will increase carotenoid and vitamin A concentrations in triacylglycerol-rich plasma (TRL). The secondary purpose of this study is to investigate the effect of a meal of high carotenoid red palm oil added to typical white gari on carotenoids and vitamin A. Adding red palm oil to white gari should be an effective method for increasing carotenoids and vitamin A status in the gari meal, and thus humans. The investigators will match the amount of retinol equivalents in the biofortified cassava gari and red palm oil-containing white cassava gari. This will let us compare their effectiveness at increasing carotenoid and vitamin A concentrations in the TRL plasma fraction after consumption. This will allow us to compare their bioavailability and bioconversion efficiencies.

Inclusion criteria

• healthy
• non-pregnant, non-lactating
• premenopausal women
• non-smoking
• body mass index between 18 and 35
• total cholesterol concentrations between 90 and 225 mg/dL
• blood pressure under 140/90 mm Hg

Exclusion criteria

• anemia, Hemoglobin less than 11.5 g/dL
• medications such as gemfibrozil, niacin, lovastatin, simvastatin, ezetimibe)
• medications that affect retinoid or carotenoid metabolism (Accutane)
• medications that impair fat absorption (Xenical, orlistat)
• dietary supplements containing vitamin A