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beta-Carotene absorption and cleavage in rats is affected by the vitamin A concentration of the diet.
J Nutr. 1996 Feb; 126(2):499-508.JN

Abstract

The purpose of this study was to examine whether intestinal beta-carotene cleavage activity, measured with the dioxygenase assay, is affected by vitamin A intake and whether this in vitro activity is a determinant of beta-carotene cleavage in vivo, measured in lymph-cannulated rats. Six groups of 10-20 rats were fed a diet with a low, normal or high retinyl palmitate concentration (120 RE, 1200 RE and 12,000 RE per kg, respectively) for 14 to 18 wk, either supplemented or not with 50 mg beta-carotene/kg in the last 6 wk. Intestinal dioxygenase activity was 90% higher (P < 0.05) in the animals fed the unsupplemented low vitamin A diet than in the animals fed the unsupplemented high vitamin A diet, whereas in beta-carotene-supplemented rats intestinal dioxygenase activity was significantly lower than in unsupplemented rats. The molar ratio between retinyl esters and beta-carotene in lymph collected over 8 h after a single intestinal dose of beta-carotene (250 micrograms) to beta-carotene-unsupplemented rats fed the three levels of vitamin A was correlated with intestinal dioxygenase activity (r = 0.66, P = 0.003). Dioxygenase activity in the liver was not affected by the vitamin A concentration of the diet but was 70% higher in the beta-carotene-supplemented rats. Based on the difference in liver vitamin A contents between beta-carotene-supplemented and unsupplemented rats we estimated beta-carotene conversion factors of 9:1 for the rats fed the high vitamin A diet and 4:1 for the rats fed the normal and low vitamin A diets. Intestinal beta-carotene cleavage activity is higher in vitamin A-deficient rats than in rats with a high intake of either vitamin A or beta-carotene. The intestinal dioxygenase activity as measured in vitro is an adequate indicator of in vivo beta-carotene cleavage activity.

Authors+Show Affiliations

Department of Physiology and Kinetics, TNO Nutrition and Food Research Institute, Zeist, Netherlands.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

8632224

Citation

van Vliet, T, et al. "Beta-Carotene Absorption and Cleavage in Rats Is Affected By the Vitamin a Concentration of the Diet." The Journal of Nutrition, vol. 126, no. 2, 1996, pp. 499-508.
van Vliet T, van Vlissingen MF, van Schaik F, et al. Beta-Carotene absorption and cleavage in rats is affected by the vitamin A concentration of the diet. J Nutr. 1996;126(2):499-508.
van Vliet, T., van Vlissingen, M. F., van Schaik, F., & van den Berg, H. (1996). Beta-Carotene absorption and cleavage in rats is affected by the vitamin A concentration of the diet. The Journal of Nutrition, 126(2), 499-508.
van Vliet T, et al. Beta-Carotene Absorption and Cleavage in Rats Is Affected By the Vitamin a Concentration of the Diet. J Nutr. 1996;126(2):499-508. PubMed PMID: 8632224.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - beta-Carotene absorption and cleavage in rats is affected by the vitamin A concentration of the diet. AU - van Vliet,T, AU - van Vlissingen,M F, AU - van Schaik,F, AU - van den Berg,H, PY - 1996/2/1/pubmed PY - 1996/2/1/medline PY - 1996/2/1/entrez SP - 499 EP - 508 JF - The Journal of nutrition JO - J Nutr VL - 126 IS - 2 N2 - The purpose of this study was to examine whether intestinal beta-carotene cleavage activity, measured with the dioxygenase assay, is affected by vitamin A intake and whether this in vitro activity is a determinant of beta-carotene cleavage in vivo, measured in lymph-cannulated rats. Six groups of 10-20 rats were fed a diet with a low, normal or high retinyl palmitate concentration (120 RE, 1200 RE and 12,000 RE per kg, respectively) for 14 to 18 wk, either supplemented or not with 50 mg beta-carotene/kg in the last 6 wk. Intestinal dioxygenase activity was 90% higher (P < 0.05) in the animals fed the unsupplemented low vitamin A diet than in the animals fed the unsupplemented high vitamin A diet, whereas in beta-carotene-supplemented rats intestinal dioxygenase activity was significantly lower than in unsupplemented rats. The molar ratio between retinyl esters and beta-carotene in lymph collected over 8 h after a single intestinal dose of beta-carotene (250 micrograms) to beta-carotene-unsupplemented rats fed the three levels of vitamin A was correlated with intestinal dioxygenase activity (r = 0.66, P = 0.003). Dioxygenase activity in the liver was not affected by the vitamin A concentration of the diet but was 70% higher in the beta-carotene-supplemented rats. Based on the difference in liver vitamin A contents between beta-carotene-supplemented and unsupplemented rats we estimated beta-carotene conversion factors of 9:1 for the rats fed the high vitamin A diet and 4:1 for the rats fed the normal and low vitamin A diets. Intestinal beta-carotene cleavage activity is higher in vitamin A-deficient rats than in rats with a high intake of either vitamin A or beta-carotene. The intestinal dioxygenase activity as measured in vitro is an adequate indicator of in vivo beta-carotene cleavage activity. SN - 0022-3166 UR - https://www.unboundmedicine.com/medline/citation/8632224/beta_Carotene_absorption_and_cleavage_in_rats_is_affected_by_the_vitamin_A_concentration_of_the_diet_ L2 - https://academic.oup.com/jn/article-lookup/doi/10.1093/jn/126.2.499 DB - PRIME DP - Unbound Medicine ER -