Natural source: Plant extract, Blakeslea trispora fermentation. Fermented also available

Beta carotene is used in foods to provide color (margarine would look as white as shortening without it). Another similar molecule, annatto is used in cheeses, and another famous carotenoid dye, saffron is used to color rice and other foods.

Beta carotene is sometimes added to products for its anti-oxidant effects, to keep fats from going rancid.

The body turns it into Vitamin A, and beta carotene is sometimes added to foods or vitamin supplements as a nutrient.

The same long chains of conjugated double bonds (alternating single and double bonds) that give the carotenes their colors are also the reason they make good anti-oxidants. The can mop up oxygen free radicals and dissipate their energy.