α-Carotene is part of the Carotenoid family, and is one of the most abundant Carotenoids in a healthy diet. Your body can convert α and β-Carotene into Vitamin A for the maintenance of healthy skin and bones, good vision, and a robust immune system. However, α-Carotene may be even more effective than β-Carotene in its role as an antioxidant. α-Carotene may help prevent cancer by stimulating cell-to-cell communication, a process which researchers now believe is necessary to ensure proper cell division.

α-Carotene contains flavonoids, which are antioxidant substances that give colour and flavour to many orange- and red-coloured fruits and vegetables. Carrots, sweet potatoes, squash, broccoli, kale, cantaloupe, brussels sprouts, kiwi, spinach, mangos, squash, and spinach are all good sources of alpha-carotene. Many flavonoids in fruits and vegetables are in the skin, so it’s best not to peel fruits and vegetables when possible. However, lightly steaming some foods, such as carrots and spinach, can actually improve the body’s ability to absorb them.

α-Carotene is a fat-soluble substance, which requires the presence of dietary fat for proper absorption. Medical conditions that interfere with the digestion of fats, such as Crohn’s disease, cystic fibrosis, surgical removal of the stomach, pancreatic enzyme deficiency, and gall bladder and liver disease, can inhibit the body’s ability to absorb α-Carotene and other Carotenoids.

People that take cholesterol-lowering medications, smokers, those that regularly consume alcohol, and those that have diets low in calories or lacking fruits and vegetables may also have lower than normal blood levels of α-Carotene. α-Carotene is available (with other Carotenoids) in supplements containing either the algae Dunaliella or mixed carotenes from palm oil. If you smoke, use Carotenoid supplements with caution. There have been some studies that indicate Carotenoid supplements may do more harm than good for smokers.

β-Carotene is a strongly colored red-orange pigment abundant in plants and fruits. It is an organic compound and chemically is classified as a hydrocarbon and specifically as a terpenoid (isoprenoid), reflecting its derivation from isoprene units. β-Carotene is biosynthesized from GeranylGeranyl Pyrophosphate. It is a member of the carotenes, which are Tetraterpenes, synthesized biochemically from eight isoprene units and thus having 40 carbons. Among this general class of Carotenes, β-Carotene is distinguished by having beta-rings at both ends of the molecule. Absorption of β-Carotene is enhanced if eaten with fats, as carotenes are fat soluble.

Carotene is the substance in carrots, pumpkins and sweet potatoes that colors them orange and is the most common form of carotene in plants. In nature, β-Carotene is a precursor (inactive form) to Vitamin A via the action of β-Carotene 15,15'-monooxygenase. Isolation of β-Carotene from fruits abundant in carotenoids is commonly done using column chromatography. It can also be extracted from the beta-carotene rich algae, Dunaliella Salina. The separation of β-Carotene from the mixture of other carotenoids is based on the polarity of a compound. β-Carotene is a non-polar compound, so it is separated with a non-polar solvent such as hexane. Being highly conjugated, it is deeply colored, and as a hydrocarbon lacking functional groups, it is very lipophilic.

β-Carotene has been used to treat various disorders such as erythropoietic protoporphyria. It has also been used to reduce the risk of breast cancer in women before menopause, and the risk of age-related macular degeneration (AMD).

Lycopene is not an essential nutrient for humans, but is commonly found in the diet mainly from dishes prepared from tomatoes. When absorbed from the intestine, lycopene is transported in the blood by various lipoproteins and accumulates primarily in the blood, adipose tissue, skin, liver, and adrenal glands, but can be found in most tissues.

Fruits and vegetables that are high in lycopene include autumn olive, gac, tomatoes, watermelon, pink grapefruit, pink guava, papaya, seabuckthorn, wolfberry (goji, a berry relative of tomato), and rosehip.

Lycopene is a naturally occurring chemical that gives fruits and vegetables a red color. It is one of a number of pigments called carotenoids. Lycopene is found in watermelons, pink grapefruits, apricots, and pink guavas. It is found in particularly high amounts in tomatoes and tomato products. In North America, 85% of dietary lycopene comes from tomato products such as tomato juice or paste. One cup (240 mL) of tomato juice provides about 23 mg of lycopene. Processing raw tomatoes using heat (in the making of tomato juice, tomato paste or ketchup, for example) actually changes the lycopene in the raw product into a form that is easier for the body to use. The lycopene in supplements is about as easy for the body to use as lycopene found in food.

People take lycopene for preventing heart disease, "hardening of the arteries" (atherosclerosis); and cancer of the prostate, breast, lung, bladder, ovaries, colon, and pancreas. Lycopene is also used for treating human papilloma virus (HPV) infection, which is a major cause of uterine cancer. Some people also use lycopene for cataracts and asthma.