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Carotenoids are plant pigments that are present in a variety of colors such as orange, yellow, red and purple. These pigments are responsible for the bright coloration of fruits and flowers; serve as a source of antioxidants, and vitamin A.
In human beings the carotenoids have been noted to serve multiple functions. One of the activities widely known is their function as the provitamin A that can be converted to vitamin A by the body. The role of carotenoids as antioxidants has also been well established. In the recent decades, the role of carotenoid in the immunity is being widely researched.

Prevention of Infections

Several studies have reported the benefits of administration of carotenoids. It was reported that carotenoids in the form of beta carotene supplements were able to prevent the occurrence of a number of infections related to the bladder, kidney, ear and stomach. The ability of the carotenoids to prevent the occurrence of infections was attributed to the effects of carotenoids on the immune system. It was believed that carotenoids enhanced the activity of the immune system and hence prevented infections.

Effects on the Thymus

The administration of beta carotene had a marked effect on the functioning of the thymus gland where the formation of the T-lymphocytes takes place. Studies have reported an increase in the growth of the thymus gland and also in the production of lymphocytes following administration of carotenoids.The thymus gland generally begins to degenerate as age progresses which may be attributed as one of the causes for an increased number of infections in older adults. Therefore, carotenoid supplementation can be beneficial in individuals with decreased immunity.

Carotenoids Influence onImmune Cell Function and Cancer

Oral supplementation of beta carotenoids also increased the activity of natural killer (NK) cells, macrophages and enhanced the secretion of chemical mediators in the immune system. Neutrophils are one of the major cells that carry on the destruction of harmful microorganisms after being recognized by the immune system. Neutrophils engulf the microorganisms or their proteins and destroy them by producing reactive oxygen species (ROS). ROS can be self destroying also causes damage in the DNA structure, modifies the proteins and destroys the cell membrane. Administration of carotenoids was noted to decrease these effects of the ROS on neutrophils and protect them from being destroyed.

Cancer Prevention

The benefits of several phytonutrients in the prevention of cancer have been well established. The efficacy of carotenoids in the prevention of a number of cancers has been demonstrated in a many different studies. The cancer protective ability of carotenoids like other phytoproteins has been attributed to its effects on the immune system. Protection of the immune cells and enhancing their function effectively controls the progression of the cancer cells and also causes death of the cancer cells.5

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  • 2. Daniel, L. R., Chew, B. P., Tanaka, T. S. & Tjoelker, L. W. Carotene and vitamin A effects on bovine phagocyte function in vitro during the peripartum period. J. Dairy Sci. 1990, 74: 124–131
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  • 4. Walrand S, Farges MC, Dehaese O, Cardinault N, et al. In vivo and in vitro evidences that carotenoids could modulate the neutrophil respiratory burst during dietary manipulation. Eur J Nutr. 2005 Mar, 44(2):114-20. Epub 2004 May 6
  • 5. Hughes DA. Effects of carotenoids on human immune function. Proc Nutr Soc. 1999 Aug, 58(3):713-8
  • Photo courtesy of Julie Gibbons by Flickr :