Bioavailability of β-carotene (βC) from purple carrots is the same as typical orange carrots while high-βC carrots increase βC stores in Mongolian gerbils(Meriones unguiculatus)

Abstract

Vitamin A (VA) deficiency is a worldwide public health problem. Biofortifying existing sources of b-carotene (bC) and increasing dietary bC could help combat the issue. Two studies were performed to investigate the relative bC bioavailability of a bC supplement to purple, high-bC orange, and typical orange carrots using Mongolian gerbils (Meriones unguiculatus). In study 1, which used a traditional bioavailability design, gerbils (n 32) received a diet containing orange, purple, or white carrot powder, or white carrot powder þ a bC supplement. In study 2, which included bC-biofortified carrots, gerbils (n 39) received orange, high-bC orange, purple, or white carrot powder in their diet. Both studies lasted 21 d and the gerbils were killed to determine the effect of carrot type or supplement on serum and liver bC, a-carotene, and VA concentrations. Liver stores of bC or VA in the gerbils did not differ between orange and purple carrot diets when equal amounts of bC from each of the diets were consumed (P.0·05). Both the orange and purple carrot diet resulted in higher liver VA compared with the supplement (P, 0·05). HighbC carrots resulted in more than 2-fold higher bC and 1·1 times greater VA liver stores compared with typical orange carrots (P, 0·05). These results suggest that high-bC carrots may be an alternative source of VA to typical carrots in areas of VA deficiency. Second, phenolics including anthocyanins and phenolic acids in purple carrot do not interfere with the bioavailability of bC from purple carrots. b-Carotene: Gerbils: Vitamin A: Carrots: Biofortification Vitamin A (VA) deficiency is a worldwide public health problem in more than 118 countries; 100 to 140 million children are VA deficient. Of those VA-deficient children, up to 500 000 children will become blind every year; half of those children will die within 1 year of losing their sight (World Health Organization, 2003). Provitamin A carotenoids are a major source of dietary VA in a large proportion of the world's population and b-carotene (bC) is the most common provitamin A carotenoid (International Vitamin A Consultative Group, 1999). One long-term solution proposed to combat VA deficiency is gardening and preserving fruits and vegetables in order to maintain VA status (World Health Organization, 2003). Carrots (Daucus carota L.) are grown worldwide and a strain of carrots genetically selected to have high bC (high-bC orange) was developed in hopes of improving VA status in deficient areas of the world (Simon et al. 1989;Simon, 1990).bC absorption from vegetables is highly variable and affected by a number of factors (Castenmiller & West, 1998;Tanumihardjo, 2002). Relative bioavailability of bC ranges between 19 and 34 % in carrots (van het Hof et al. 2000), although this range is complicated by bioconversion to retinol. Furthermore, responses to orally ingested bC appear to be somewhat independent of dose. Brown et al. (1989) found that 30 mg bC produced a peak response in plasma bC only 1·6 times higher than a 12 mg dose of bC, sugges...

Maize Genotype and Food Matrix Affect the Provitamin A Carotenoid Bioefficacy from Staple and Carrot-Fortified Feeds in Mongolian Gerbils (Meriones unguiculatus)

“…34 In humans and gerbils, extra dietary carotenoid that is not converted to retinol is absorbed and stored, but not currently considered when determining bioavailability. The βC absorbed from biofortified carrot and stored in the liver was 2650% higher in the prior study at 3.3% 21 than the current study at 0.5% of the feed. Carrot intake, in contrast to VA supplements, impacts antioxidant capacity of tissues and may support optimal health.…”

“…In prior studies, high-βC carrots provided an abundant amount of retinol to gerbils. 21 In study 2, the hypothesis was that small amounts of high-βC carrots will be an effective complementary food to maintain liver retinol reserves in gerbils despite potential effects of the combined food matrix.…”

Sweet Potato β-Carotene Bioefficacy Is Enhanced by Dietary Fat and Not Reduced by Soluble Fiber Intake in Mongolian Gerbils

“…Likewise, serum retinol concentrations improved in young children after the introduction of OFSP into Mozambique (14). The Mongolian gerbil model (15) has been used to assess bioefficacy of a-carotene (16), bC (17)(18)(19)(20), and b-cryptoxanthin (21) from supplements, carrots (17)(18)(19), maize (22), cassava (23), and green vegetables (23). The gerbil model provides estimates of dietary provitamin A bioefficacy and is ideal for studying whole-body metabolism.…”

Relative contribution of α-carotene to postprandial vitamin A concentrations in healthy humans after carrot consumption

“…Carrots have been well studied for provitamin A conversion, with most studies focusing solely on determining the total carotene contribution to vitamin A (17)(18)(19). Although other groups have demonstrated that a-retinol is esterified and cleared from the enterocyte into plasma in animal models (9,11,28), this is the first postprandial study, to our knowledge, to follow aRP in human plasma.…”

“…The structural similarity of a-retinyl esters to retinyl esters causes co-elution with most HPLC methods (11,14,15). Although studies have assessed the absorption and conversion of a-and b-carotene to vitamin A in animals (9,10,17,18) and humans (19,20), vitamin A equivalence has likely been overestimated because of the contribution of a-retinyl esters to the newly converted retinyl esters. We developed a method to separate a-retinyl esters from retinyl esters for a more accurate quantitation of vitamin A derived from a meal containing a-carotene (21).…”