Vita OH All-trans retinol β Carotene Fig 3.1 Structures of all-trans-retinol and B-carotene 4: I(Gopalan et al, 1989) 6: 1(Report of a Joint FAO/WHO expert consultation 1988) 12: 1(Report of the Institute of Medicine 2001) 21: 1 and 26: 1(de Pee et al, 1998; Khan et al, 1998; van het Hof et al, 1999) Assuming that 100g DGLV contains 3000ug B-carotene and a child of 4 years needs an RNI of 400ug RE/day then using bioconversion factor 12:1 21: 1 or 26: 1, the child would need 160g, 280g or 360g of DGLv meet requirements 3.4.2 Equivalence factor as calculated by IoM In January 2001, the US National Academy of Sciences/Institute of Medicine (OM)announced a new equivalence factor(12: 1) for the conversion of B- carotene to retinol. The basis for formulating the equivalency factor was to relate the absorption of B-carotene in a principally mixed vegetable diet to that from oil in healthy and nutritionally-adequate individuals. The recommendations were based on a product of relative absorption of B-carotene in mixed vegetable diet 1: 6)(van het Hof et al, 1999)to the amount of retinol formed (1 ug) when 2ug B-carotene was fed in oil (Sauberlich et al, 1974). In the van het Hof study, the increase in serum B-carotene concentration after consumption of B-carotene-rich egetables was 1/7 or 14% of the increase after consumption of B-carotene in oil The Institute of Medicine (IOM)(2001)adjusted the value to 1/6 or 17%, because of the low fruit content in the diet used. From these two studies the iom con cluded that the bioefficacy of B-carotene in oil was(100%*0.94)/2=47%0 (Sauberlich et al, 1974)and 17% from mixed vegetables(van het Hof et al, 1999) Thus bioefficacy from vegetables in a mixed diet was 17%*0.47=8%0, that is 12ug B-carotene in food has the same vitamin A activity as l ug retinol. The• 4 :1 (Gopalan et al, 1989) • 6 :1 (Report of a Joint FAO/WHO expert consultation 1988) • 12 :1 (Report of the Institute of Medicine 2001) • 21 :1 and 26 :1 (de Pee et al, 1998; Khan et al, 1998; van het Hof et al, 1999) Assuming that 100 g DGLV contains 3000mg b-carotene and a child of 4 years needs an RNI of 400mg RE/day then using bioconversion factors of 12 :1, 21 :1 or 26 :1, the child would need 160 g, 280 g or 360 g of DGLV each day to meet requirements. 3.4.2 Equivalence factor as calculated by IOM In January 2001, the US National Academy of Sciences/Institute of Medicine (IOM) announced a new equivalence factor (12 :1) for the conversion of b￾carotene to retinol. The basis for formulating the equivalency factor was to relate the absorption of b-carotene in a principally mixed vegetable diet to that from oil in healthy and nutritionally-adequate individuals. The recommendations were based on a product of relative absorption of b-carotene in mixed vegetable diet (1 :6) (van het Hof et al, 1999) to the amount of retinol formed (1mg) when 2mg b-carotene was fed in oil (Sauberlich et al, 1974). In the van het Hof study, the increase in serum b-carotene concentration after consumption of b-carotene-rich vegetables was 1/7 or 14% of the increase after consumption of b-carotene in oil. The Institute of Medicine (IOM) (2001) adjusted the value to 1/6 or 17%, because of the low fruit content in the diet used. From these two studies, the IOM con￾cluded that the bioefficacy of b-carotene in oil was (100% * 0.94)/2 = 47% (Sauberlich et al, 1974) and 17% from mixed vegetables (van het Hof et al, 1999). Thus bioefficacy from vegetables in a mixed diet was 17% * 0.47 = 8%, that is 12mg b-carotene in food has the same vitamin A activity as 1mg retinol. The Vitamins 39 Fig. 3.1 Structures of all-trans-retinol and b-carotene