The carotenoids and their derivatives are generally responsible for the yellow to deep-red colour of fruits, vegetables, cereals and crude palm oil. Carotenoids are the precursors of vitamin A, with -carotene having the highest provitamin A activity. Vitamins A and D . A traditional source of vitamin A is butterfat. Fish oils are a common source of vitamin D. Margarines, which are fortified with vitamins A and D by law in most countries, also make an important contribution to ensuring adequate intakes of these nutrients.
Cholesterol is the principal sterol of animal products.
Methylsterols and triterpene alcohols . Corresponding concentrations of triterpene alcohols, comprised of five condensed cyclohexane rings, are 0.01 to 1.2 percent. Rice bran oil is the only one at the upper level. The predominant hydrocarbon in dietary fat is squalene. It is an intermediate in the synthesis of sterol from acetate, and it is found in particularly high quantities in some fish and olive oil.