Possible Interaction: Vitamin A and Beta Carotene

“Results showed that the incorporation of beta-carotene sources (mainly in the form of red sweet potatoes) into the meal significantly increased serum retinol concentrations.”

“BACKGROUND Recent evidence suggests that the vitamin A equivalency of beta-carotene from plant sources is lower than previously estimated.”

“Infants born to mothers supplemented with beta-carotene + zinc had higher plasma retinol concentrations, with the frequency of vitamin A deficiency reduced by >30% compared with the other 3 groups.”

“The conversion factor of beta-carotene to retinol varied from 2.4 to 20.2, and the average conversion factor was 9.1 to 1 by wt or 4.8 to 1 by mol.”

“This represented reductions of 40% (P<0.04) and 49% (P<0.01) among those who received vitamin A and beta carotene.”

“Combined with our previous work showing a strong correlation between BAL and lung tissue nutrient levels, these findings suggest that supplementation with beta-carotene and vitamin A results in increased lung tissue as well as BAL cell levels of beta-carotene , with little change in lung retinol.”

“We determined whether serum carotenoid or retinol concentrations were altered by beta-carotene supplementation in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study and whether such effects were modified by alcohol consumption or cigarette use.”

“… beta-carotene in … of vitamin A : 0.27 ng beta-carotene per 10(6) cells in the placebo group, 1.79 ng following the intake of beta-carotene (… ng after beta-carotene (180 mg/week for 16 weeks) plus vitamin A (100,000 IU/week for 16 weeks) consumption.”

“There was a strong positive association between serum beta-carotene and serum retinol (r = 0.44, P < 0.001), suggesting those with higher retinol levels had a higher carotene intake.”

“Reported conversion ratios of beta-carotene to vitamin A in humans in vivo, depending on conditions, range from 2:1 to 26:1 (microgram/microgram).”