Location: Immunity and Disease Prevention Research2012 Annual Report
1a. Objectives (from AD-416):
Biofortification of staple food crops is a promising strategy for increasing dietary Vitamin A intake and improving Vitamin A status in populations at risk of deficiency. The purpose of this study is to determine the Vitamin A equivalence of carotenoids in high-carotenoid varieties of cassava. #2. The additional purpose of this study is to determine the Vitamin A equivalence of carotenoids in high-carotenoid varieties of cassava gari.
1b. Approach (from AD-416):
We plan to conduct a single site Phase II intervention study in healthy adult women. Women will serve as their own controls, and will be fed three treatments in random order: a single meal of white, non-biofortified low-carotenoid cassava with oil, a similar meal of bio-fortified cassava that is high in carotenoids without oil, and a similar meal of bio-fortified cassava with oil. Carotenoids and vitamin A will be measured in the triacylglycerol-rich lipoprotein (TRL) fraction of plasma by standard methods involving ultracentrifugation (to concentrate the TRL fraction) followed by reversed-phase HPLC using electrochemical detection. We plan to collect sufficient data to identify the times of the first appearance and peak concentrations of retinol, retinyl esters, alpha-carotene (AC), beta-carotene (BC), beta-carotene isomers (BCI) and cryptoxanthin (CX) in TRL when a single meal containing moderately high amounts of carotenoids from bio-fortified cassava is fed to healthy adult women. We will use these data to determine the vitamin A equivalency of bio-fortified cassava in adult women. #2. Garification detoxifies cassava and increases its palatability, but destroys carotenoids in the process. We plan to compare the effects of two fermentation times (3 and 4 days), two roasting temperatures, and several sequential roasting times on the retention of carotenoids in gari made from three different biofortified cultivars of cassava. The goals of this project, henceforth called the ‘Gari project’, are to: 1) develop standardized procedures for making gari from biofortified cassava that will decrease variability between preparations and thus enhance our ability to identify differences in methods and cultivars that result in higher carotenoid concentrations: and 2) to identify the cultivar and garification treatment that has the highest carotenoid concentration after garification.
3. Progress Report:
This study extends the scope and range of Objective 3B of the parent project, “Estimate the impact of daily consumption of food sources of CX or B-carotene (BC) on plasma and breast milk concentrations of CX, BC and retinol” to a staple crop, biofortified cassava. Cassava is a staple crop in parts of Africa, South America, and Asia; but most varieties of cassava lack beta-carotene, a major source of vitamin A, which is essential for normal development and eyesight. Cassava also contains chemicals that form cyanide, which must be removed during preparation. Recently, careful crossbreeding of cassava has generated ‘biofortified’ varieties with good amounts of beta-carotene. Feeding ‘biofortified’ cassava increased beta-carotene and vitamin A concentrations in women. The vitamin A equivalence of biofortified cassava was very good, about 4 micrograms beta-carotene: 1 microgram retinol. Furthermore, the mild food processing methods we used successfully removed all of the cyanide from the cassava, but retained most of the beta-carotene. Finally, only a small amount of fat (6 grams) was needed to aid beta-carotene absorption from the ‘biofortified’ cassava meal. Adding more fat to the diet did not improve results. Therefore, eating properly prepared ‘biofortified’ cassava has low risk, and can increase beta-carotene and vitamin A in humans. The second component of this project, involving gari, is in its early stages. However, collaborators from the International Center for Tropical Agriculture (CIAT-Nigeria) have grown biofortifed cassava with moderate concentrations of beta-carotene and cyanogenic glycosides for this project, and shipped it to the WHNRC with aid from HarvestPlus. Methods for measuring carotenoids, vitamin A, and cyanogenic glycosides in cassava have been developed, and a food preparation(garification) plan has been approved by all collaborators on the project. Finally, permission has been obtained to make food (garify) from the cassava at the California Processing Tomato Industry Pilot Plant of the University of California Davis.