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Copyright 2013 Natural Standard (
May 2012

Excessive Beta-Carotene May Be Harmful

Consuming excessive amounts of beta-carotene may potentially be harmful, a study reported.

Researchers examined the effects of consuming beta-carotene, which converts to vitamin A in the body and helps maintain visual, bone and skin health. They exposed a series of molecules derived from beta-carotene to conditions similar to what would occur in the human body, and produced a total of 11 synthetic molecules.

The scientists discovered that nearly half of the molecules produced acted as vitamin A inhibitors, potentially blocking the benefits of this antioxidant. They reported that these particular molecules were very common byproducts of beta-carotene metabolism, as they were present in all six blood samples taken from healthy volunteers.

The authors concluded that consuming excessive beta-carotene may have counterproductive effects. However, more evidence is needed to better understand these results.

The name "carotene" was first coined in the early 19th Century by the scientist Wachenroder after he crystallized this compound from carrot roots. Beta-carotene is a member of the carotenoids, which are highly pigmented (red, orange, yellow), fat-soluble compounds naturally present in many fruits, grains, oils, and vegetables (green plants, carrots, sweet potatoes, squash, spinach, apricots and green peppers). Alpha, beta and gamma carotene are considered provitamins because they can be converted to active vitamin A.

The carotenes possess antioxidant properties. Vitamin A serves several biological functions including involvement in the synthesis of certain glycoproteins. Vitamin A deficiency leads to abnormal bone development, disorders of the reproductive system, xerophthalmia (a drying condition of the cornea of the eye) and ultimately death.

Commercially available beta-carotene is produced synthetically or from palm oil, algae or fungi. Beta-carotene is converted to retinol, which is essential for vision and is subsequently converted to retinoic acid, which is used for processes involving growth and cell differentiation.

For more information about beta-carotene, please visit Natural Standard's Foods, Herbs & Supplements Database.


  1. Eroglu A, Hruszkewycz DP, Dela Sena C, et al. Naturally Occurring Eccentric Cleavage Products of Provitamin A β-Carotene Function as Antagonists of Retinoic Acid Receptors. J Biol Chem. 2012 May 4;287(19):15886-95. Epub 2012 Mar 14. View Abstract
  2. Natural Standard: The Authority on Integrative Medicine.
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