Carotenoids Explained: Provitamin A and Non-Provitamin A Types

How the sources define the terms

A review sorts the groups this way.

MedlinePlus says the most common provitamin A carotenoid is beta-carotene, and that once eaten, provitamin A carotenoids are converted into vitamin A. [1] Another review says humans cannot make carotenoids and must get them from food or supplements, and that lutein and zeaxanthin make up the macular pigment in the eye. [3] Another review says evidence has accumulated that carotenoids that cannot be converted to vitamin A may still take part in health-promoting biological actions, which is a research finding, not a proven benefit. [4]

Where they are found

The NHS names yellow, red and green (leafy) vegetables, such as spinach, carrots, sweet potatoes and red peppers, plus yellow fruit such as mango, papaya and apricots, as main sources of beta-carotene. [5] MedlinePlus lists orange and yellow vegetables and fruits (carrots, sweet potatoes, mangos, cantaloupe) and dark green leafy vegetables as vitamin A sources, and says the brighter the color the more carotenoids. [1] Absorption improves when these foods are eaten with a small amount of fat. [1] See tomatoes (lycopene) and leafy greens (lutein).

Why the type matters for supplements

• Beta-carotene: supplements raised lung cancer risk in smokers in two large trials. [6][7] The NCCIH names smokers and people exposed to asbestos as the highest-risk groups. [8] MedlinePlus says large amounts of beta-carotene will not make you seriously ill but can turn skin yellow or orange. [1]
• Lutein and zeaxanthin: studied as part of the AREDS2 eye formula; results should not be applied to beta-carotene or to other people. [9]
• Lycopene: studied for skin redness after UV light in a meta-analysis. [10]
• Vitamin A (retinol) is different: MedlinePlus says large doses of vitamin A in pregnant women can cause birth defects. [1] Do not apply that statement to carotenoids; the sources read do not say it does, and do not say it does not. Ask a clinician.

Never transfer a finding between carotenoids: a result for beta-carotene does not tell you about lutein, and food results do not tell you about supplements. Compare the two sides on antioxidants in food vs supplements.

Official figures

MedlinePlus (citing US Dietary Reference Intakes, reviewed January 2025) gives vitamin A RDAs of 900 mcg a day for males 14 and older and 700 mcg a day for females 14 and older. [1] The NHS (UK, 2020) gives 700 µg (men) and 600 µg (women) a day for adults 19 to 64. [5] We did not find, in sources we could read, an intake recommendation for alpha-carotene, beta-cryptoxanthin, lutein, zeaxanthin or lycopene, and the NIH Office of Dietary Supplements page could not be read this session, so none is given.