Beta-carotene is the main safe dietary source of vitamin A, essential for normal growth and development, immune system function, and vision (1).

 

Beta-carotene has antioxidant properties that can help neutralize free radicals – reactive oxygen molecules potentially damaging lipids in cell membranes and genetic material, which may lead to the development of cardiovascular disease and cancer (2).

 

At present, it is unclear whether some beneficial effects of beta-carotene and other carotenoids in humans are a result of their antioxidant activity or other non-antioxidant mechanisms. The relevance of deactivating reactive oxygen species to human health, potentially preventing diseases such as cancer and coronary heart disease, is not clear.

 

In vitro studies indicate that carotenoids can also inhibit the oxidation of fats under certain conditions. They may have anti-atherosclerotic potential, but their effects in humans appear to be more complex (3).

 

Beta-carotene and other carotenoids can facilitate communication between neighboring cells by stimulating the synthesis of proteins that form pores in cell membranes, allowing communication through the exchange of small molecules (4). This effect appears unrelated to the vitamin A or antioxidant activities of various carotenoids (5).

 

Some clinical trials have found that beta-carotene supplementation improves several parameters of immune function, such as increasing the number of white blood cells and the activity of natural killer cells (6, 7, 8). Nevertheless, as vitamin A is essential for normal immune system function, it is difficult to determine whether the effects of beta-carotene are related to their vitamin A activity or other activities of carotenoids.