Bioavailability of beta-carotene in humans

Abstract

Normal healthy volunteers were studied after they ingested various beta-carotene doses. Daily administration of 15 or 45 mg beta-carotene resulted in significant increase in plasma beta-carotene levels. The extent of increase and the pattern of plasma beta-carotene levels showed substantial interindividual variation. Absorption of beta-carotene was affected by dietary fat concentration. Individuals placed on a high-fat diet showed significant increases in plasma beta-carotene as compared with those placed on a low-fat diet. Pharmacological doses of beta-carotene (45 and 90 mg) were used in intermittent schedules (5-6 d intervals) without altering the steady state of beta-carotene plasma levels. Yellowing of the skin occasionally occurred during daily dosing with 45 mg beta-carotene without evidence of toxicity. The observed individual variation in bioavailability of beta-carotene raises questions regarding clinical use of this micronutrient. It appears that determination of target plasma beta-carotene concentrations is essential for effective use of this compound in prevention or treatment.

Estimation of carotenoid accessibility from carrots determined by an in vitro digestion method

“…Another way of reducing matrix effects is by homogenization or particle size reduction (van Zeben & Hendriks, 1948;Gärtner et al, 1997;Castenmiller et al, 1999;van het Hof et al, 1999). Dietary fat, as well, has a documented positive effect on bioavailability of carotenoids (Roels et al, 1958;Dimitrov et al, 1988;Shiau et al, 1994;Jalal et al, 1998), although the amount of fat required to optimize carotenoid bioavailability has not been clearly identified.…”

“…The most commonly applied method includes measuring increases in plasma concentrations of carotenoids or retinol in humans following administration of an acute or chronic dose of an isolated carotenoid or a carotenoid-containing food (Brown et al, 1989;Micozzi et al, 1992;Castenmiller et al, 1999;van het Hof et al, 1999). This is a relative measure, as the plasma is highly dynamic and individual responses have been reported to be highly variable (Dimitrov et al, 1988;Törrönen et al, 1996). To obtain a quantitative measure of carotenoid bioavailability, the oral -faecal balance method is a better approach (Roels et al, 1958;Shiau et al, 1994).…”

Effects of a high monounsaturated fat, tomato-rich diet on serum levels of lycopene

“…Other carotenoids and alpha-tocopherol levels also indicate no major differential effect, although the large s.d.s mean that small differences cannot be excluded. Previous studies that suggested a significant role of fat in the bioavailability of beta-carotene had compared no fat meals with meals cooked in fat (Dimitrov et al, 1988;Prince & Frisoli, 1993). Also, these studies were of short duration F 5 days (Dimitrov et al, 1988) or a single dose test (Prince & Frisoli, 1993).…”

“…The intake of carotenoid-rich foods cooked with oil increases the serum carotenoid bioavailability (Stahl & Sies, 1992). The effects of different amounts of oil in the diet on the serum concentration of beta-carotene (Jayarajan et al, 1980;Dimitrov et al, 1988;Jalal et al, 1998) and lutein (Roodenburg et al, 2000) have been studied.…”

Carotenóides como alternativa contra a hipovitaminose A

“…Dimitrov et al 27 constataram que a absorção de β-caroteno é afetada pela concentração de gordura da dieta. Ao receberem uma dieta hiperlipídica, indivíduos saudáveis apresentaram significante elevação na concentração plasmática de β-caroteno quando comparados aos indivíduos que receberam uma dieta hipolipídica.…”