karoten

Karoten, commonly called carotene, refers to a family of natural pigments found in plants, algae, and some bacteria. The best known member is beta-carotene. Carotenoids are fat-soluble, brightly colored compounds and are responsible for the orange to yellow hues of many fruits and vegetables. Chemically, carotene is a hydrocarbon with a long chain of conjugated double bonds; beta-carotene has two terminal beta-ionone rings.

Biological role and nutrition: Many carotenoids function as photosynthetic pigments and protect plant tissues from photooxidative damage. In humans, some carotenoids are provitamins; beta-carotene can be converted in the intestinal lining to retinol (active vitamin A), contributing to vision, immune function, and gene expression. Dietary carotenoids have antioxidant activity, though the extent of health benefits in humans varies by compound and intake level.

Sources and intake: Rich dietary sources include carrots, sweet potatoes, pumpkins, kale, spinach, and apricots. Dietary recommendations express vitamin A needs as retinol activity equivalents; approximately 12 micrograms of beta-carotene equal 1 microgram of retinol, with conversion efficiency affected by food matrix and individual factors.

Health considerations: Carotenoid intake from food is generally safe. High-dose beta-carotene supplements have been associated with an increased risk of lung cancer in cigarette smokers and can cause carotenemia, a harmless yellow-orange skin discoloration. They are not recommended for cancer prevention and should not replace a balanced diet.

Uses: In industry, carotenoids are used as natural colorants (for example, in food and cosmetics) and as feed additives. They are produced naturally by plants and by chemical synthesis for various applications.