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ARS Home » Pacific West Area » Davis, California » Western Human Nutrition Research Center » Immunity and Disease Prevention Research » Research » Publications at this Location » Publication #333179

Research Project: Assessing the Impact of Diet on Inflammation in Healthy and Obese Adults in a Cross-Sectional Phenotyping Study and a Longitudinal Intervention Trial

Location: Immunity and Disease Prevention Research

Title: Metabolic effects of inflammation on vitamin A and carotenoids in humans and animal models

Author
item Rubin, Lewis - Texas Tech University Health Science Center
item Ross, Catherine - Pennsylvania State University
item Stephensen, Charles
item Bohn, Torsten - Luxembourg Institute Of Health
item Tanumihardjo, Sherry - University Of Wisconsin

Submitted to: Advances in Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/8/2017
Publication Date: 3/8/2017
Citation: Rubin, L.P., Ross, C.A., Stephensen, C.B., Bohn, T., Tanumihardjo, S.A. 2017. Metabolic effects of inflammation on vitamin A and carotenoids in humans and animal models. Advances in Nutrition. 8:197-212. doi: 10.39945:an.116.014167.

Interpretive Summary: Episodes of inflammation caused by illness or other conditions alter the metabolism of vitamin A. Carotenoids can serve as precursors of vitamin A but it is not clear if carotenoid metabolism is similarly altered during episodes of inflammation. It is well-known, however, that carotenoids are associated with certain health benefits aside from their ability to be converted into vitamin A. Understanding the effects of inflammation on both vitamin A and carotenoids is key to improving health outcomes and mortality risk in infants and young children at risk of vitamin A deficiency. Serum retinol concentrations decrease transiently during inflammation and this can lead to the misdiagnosis of vitamin A deficiency. On the other hand, inflammation causes impaired vitamin A absorption and urinary losses, which can precipitate actual vitamin A deficiency. Many community-based studies show that high dietary carotenoid intake and plasma carotenoid concentrations are correlated with low risk of several chronic diseases; however, carotenoid supplementation trials were unable to confirm health benefits. It is possible that inflammation may, to a degree, confound the relationship between plasma carotenoids and disease risk. The current understanding of the relationships between inflammation and the metabolism of vitamin A and carotenoids is the topics of this review.

Technical Abstract: The association between inflammation and vitamin A metabolism and status assessment has been documented in multiple studies with animals and humans. The relationship between inflammation and carotenoid status is less clear. Nonetheless, it is well-known that carotenoids are associated with certain health benefits. Understanding these relationships is key to improving health outcomes and mortality risk in infants and young children. Hyporetinolemia occurs during inflammation and this can lead to the misdiagnosis of vitamin A deficiency. On the other hand, inflammation causes impaired vitamin A absorption and urinary losses, which can precipitate vitamin A deficiency in at-risk groups of children. Many epidemiological studies have suggested that high dietary carotenoid intake and elevated plasma concentrations are correlated with decreased risk of several chronic diseases; however, other large-scale carotenoid supplementation trials were unable to confirm health benefits. Yet it is documented that dietary carotenoids and retinoids play important roles in innate and acquired immunity and in the body’s response to inflammation. While animal models have been useful in investigating retinoid effects on developmental immunity, it is more challenging for teasing out the effects of carotenoids due to differences in absorption, kinetics, and metabolism between humans and most animal models. The current understanding of the relationships between inflammation and retinoid and carotenoid metabolism and status are the topics of this review.