Beta carotene is a carotenoid substance naturally found in plants that serves as an accessory to photosynthesis. Beta carotene is primarily responsible for the pigment in orange colored fruits and vegetables, but also contributes to the pigment in red, yellow, and green colored fruits and vegetables. Though some food sources are rich in beta carotene, including cantaloupe, broccoli, spinach, and palm oil, carrots are the major supplier of beta carotene in most people’s diets.

Beta carotene is accepted as an essential human nutrient, especially when there is a deficiency of vitamin A. In fact, when a vitamin A deficiency is suspected, blood tests measuring the levels of beta carotene are often performed as a result. Beta carotene is believed to have antioxidant properties in addition to its provitamin A function. Some studies have also concluded that beta carotene may have a positive impact on the immune system as well as anticarcinogenic effects.

Most official nutritional and health organizations, including the National Cancer Society, recommend consuming five servings of fruits and vegetables per day. A sufficient amount of beta carotene would be absorbed by following these guidelines. However, recent research has indicated that beta carotene may only be beneficial when it is consumed in its naturally occurring state, such as in fruits and vegetables, rather than in supplemental form. Further, it could be harmful for certain individuals to consume beta carotene supplements. Clinical trials have shown beta carotene supplements may increase the rate of lung cancer in smokers.

Beta carotene, like most other nutritional substances, can be obtained in adequate amounts by eating a well-balanced, healthy diet consisting of fruits and vegetables. However, a doctor may recommend beta carotene supplements for certain patients. Since beta carotene is a precursor to vitamin A through metabolism, the most common reason for testing beta carotene levels is a suspected vitamin A deficiency. Indicators of a vitamin A deficiency include vision problems, dry or inflamed eyes, unexplained hair loss or skin rash, and recurring infections. Before considering beta carotene or other nutritional supplements, you should consult your doctor.