Excess vitamin E decreases canthaxanthin absorption in the rat

Area of Science:

• Nutrition Science
• Biochemistry
• Gastroenterology

Background:

• Growing interest in antioxidants like alpha-tocopherol (alpha-Toc) and carotenoids for health benefits.
• Potential for nutrient-antioxidants to share absorptive pathways and influence each other's bioavailability, especially at high doses.

Purpose of the Study:

• To investigate the interaction between alpha-tocopherol (alpha-Toc) and the carotenoid canthaxanthin (CTX) during absorption.
• To determine if alpha-Toc affects the absorption efficiency of CTX.

Main Methods:

• Rats were infused intraduodenally with corn oil emulsions containing varying concentrations of alpha-Toc and CTX.
• A 2x4 factorial design was used to test combinations of alpha-Toc (0 or 300 mumol/L) and CTX (5-20 mumol/L).
• Absorption was quantified by measuring the recovery of CTX and alpha-Toc in mesenteric lymph.

Main Results:

• Canthaxanthin (CTX) absorption efficiency averaged 12% and was not dose-dependent in the absence of alpha-Toc.
• The presence of alpha-tocopherol (300 mumol/L) reduced CTX absorption by at least 50%.
• Alpha-tocopherol (alpha-Toc) recovery in lymph was approximately 10% and was not influenced by CTX presence.

Conclusions:

• Concurrent intake of high-dose alpha-tocopherol significantly impairs canthaxanthin absorption.
• Alpha-tocopherol may negatively affect carotenoid bioavailability.
• Further research is needed to understand the clinical implications of these nutrient interactions.