Intrinsic and Extrinsic Factors Impacting Absorption, Metabolism, and Health Effects of Dietary Carotenoids

Abstract

Carotenoids are orange, yellow, and red lipophilic pigments present in many fruit and vegetables, as well as other food groups. Some carotenoids contribute to vitamin A requirements. The consumption and blood concentrations of specific carotenoids have been associated with reduced risks of a number of chronic conditions. However, the interpretation of large, population-based observational and prospective clinical trials is often complicated by the many extrinsic and intrinsic factors that affect the physiologic response to carotenoids. Extrinsic factors affecting carotenoid bioavailability include food-based factors, such as co-consumed lipid, food processing, and molecular structure, as well as environmental factors, such as interactions with prescription drugs, smoking, or alcohol consumption. Intrinsic, physiologic factors associated with blood and tissue carotenoid concentrations include age, body composition, hormonal fluctuations, and variation in genes associated with carotenoid absorption and metabolism. To most effectively investigate carotenoid bioactivity and to utilize blood or tissue carotenoid concentrations as biomarkers of intake, investigators should either experimentally or statistically control for confounding variables affecting the bioavailability, tissue distribution, and metabolism of carotene and xanthophyll species. Although much remains to be investigated, recent advances have highlighted that lipid co-consumption, baseline vitamin A status, smoking, body mass and body fat distribution, and genetics are relevant covariates for interpreting blood serum or plasma carotenoid responses. These and other intrinsic and extrinsic factors are discussed, highlighting remaining gaps in knowledge and opportunities for future research. To provide context, we review the state of knowledge with regard to the prominent health effects of carotenoids.

Determinants and Suitability of Carotenoid Reflection Score as a Measure of Carotenoid Status

“…Fruits [4] and some animal products such as eggs and dairy contribute provitamin A, antioxidant and chemoprotective components to the diet. Carotenoids are found mainly in vegetables [5,6]. For example, carrot, kale, spinach and pumpkin are good sources of beta carotene, corn contains lutein, and tomato is a good source of lycopene [7].…”

The effect of β-carotene on the mortality of male smokers is modified by smoking and by vitamins C and E: evidence against a uniform effect of nutrient

“…of the potential health effects of BC (3,(38)(39)(40)(41)(42)(43)(44)(45)(46)(47)(48)(49)(50)(51) . Although these three large trials refuted any putative benefits of BC supplementation, the characteristics of people who get harm are still poorly understood (52,53) . This question is relevant for a better understanding of the physiology of BC in humans, i.e.…”

Genetic architecture underlying changes in carotenoid accumulation during the evolution of the Blind Mexican cavefish,Astyanax mexicanus

“…To search for other genetic changes that could influence carotenoid accumulation in cavefish, we reviewed the literature and generated a list of fifty genes that have known roles in carotenoid processing or are linked with human variation in carotenoid levels (Supplemental table 1) (Bohn et al, 2017;Moran et al, 2018;Toews et al, 2017). None of these genes are on the unplaced scaffolds that were mapped in the fat color QTL.…”

“…Chylomicrons are differentially routed to tissues based on tissue-specific expression of lipoprotein receptors. Genetic variation at each of these steps has been linked to changes in carotenoid-based traits (reviewed in Moran et al, 2018;Toews et al, 2017).…”

“…Mutations in the lipid transporter SCARB1 produce palecolored silk-worms due to decreased absorption of β-carotene (Sakudoh et al, 2013) and high expression of SCARB1 in the intestine of salmon is associated with increased carotenoid accumulation and orange muscle color (Sundvold, Helgeland, Baranski, Omholt, & Våge, 2011). In humans, single nucleotide polymorphisms in BCO1, BCO2, SCARB1 and other lipid transporters and are associated with carotenoid levels in the serum (reviewed in Moran et al, 2018). Considering the potential health benefits of carotenoids, there is commercial interest in breeding animals that produce high carotenoid levels as well as understanding what causes variation in human carotenoid absorption.…”