In a recent study published in the journal Antioxidants, researchers review existing research on the benefits of carotenoids to understand the potential use of carotenoids as nutraceuticals and functional health foods.
Study: Overview of the Potential Beneficial Effects of Carotenoids on Consumer Health and WellBeing. Image Credit: LilieGraphie / Shutterstock.com
Plants contain biologically active compounds called phytochemicals or phytonutrients with potential health benefits and uses in medicine, food, and cosmetics. Due to their ability to decrease oxidative stress, plants have also been used to treat various diseases.
Carotenoids are a group of phytonutrients with possible cardiovascular and anti-cancer benefits. These brightly-colored compounds are found in photosynthesizing organisms such as plants, cyanobacteria, and algae and are associated with chlorophyll to absorb specific wavelengths of light. Furthermore, carotenoids protect plant cells from light damage and superoxide radicals and decrease the reactivity of oxygen species.
Carotenoids are found in bright-colored vegetables, fruits, egg yolks, butter, cheese, and seafood. Apart from the selection and cultivation of staple foods that are known carotenoid sources, there is also a growing interest in exploring underused wild vegetables and fruits to discover new sources of carotenoids.
Carotenoids and their sources
There are more than 600 naturally occurring carotenoids, synthesized mainly by plants, fungi, and bacteria. All contain a conjugated double-bond system that allows them to absorb light in the 400-550 nanometer (nm) wavelength. Based on composition, these compounds are classified as carotenes, which have only carbon and hydrogen atoms, as well as xanthophylls, which also contain other oxygenated functional groups.
Carotenes, of which β-carotene is the most abundant, are found in mangos, apricots, grapes, and carrots. Lycopene is an acyclic carotene generally found in vegetables and fruits with red flesh, such as tomatoes and watermelons. Lutein is the most abundant xanthophyll, while smaller amounts of other xanthophylls, like zeaxanthin, can also be found in green vegetables and cereals.
Carrots, tomatoes, red peppers, green vegetables, mangoes, peaches, apricots, papaya, and citrus fruits are major sources of carotenoids. Beta-carotene is also found in green leafy vegetables such as spinach, kale, and lettuce.
Lycopene is mainly found in fruits and vegetables that are red-fleshed, such as tomato, watermelon, pink guava, and papaya, as well as green vegetables, such as asparagus and parsley. Green leafy vegetables, such as kale, spinach, purslane, watercress, parsley, Brussel sprouts, lettuce, and broccoli, are a significant source of lutein, while red and orange peppers are a good source of zeaxanthin.
Besides vegetables and fruits, carotenoids are also found in cereals, especially maize, dairy products, fish, and mammals that accumulate yellow fat, such as cattle and birds. As carotenoids are lipid-soluble, the bio-accessibility of carotenoids also depends on the lipid content of the diet. Additionally, the presence of other phytochemicals such as fatty acids, phytosterols, tocopherols, and polyphenols also impact the absorption of carotenoids.
Role in human health
Lycopene has the highest free radical activity among the 600 naturally occurring carotenoids and has exhibited the ability to protect deoxyribonucleic acid (DNA) from oxidative stress and prevent mutations that could cause chronic diseases. Various studies on animal models, as well as ex vivo and in vitro studies using cultured cells, have reported that carotenoids have anti-inflammatory properties and exhibit beneficial effects in lipidic and glycemic impairments, as well as the apoptosis and proliferation of tumor cells.
Lycopene has been used as a nutritional supplement in the treatment of various cardiovascular diseases and appears to reduce cholesterol oxidation, enhance antioxidant properties, and reduce oxidative stress. Lycopene has also shown protective properties during arterial transplants by modulating the production of proteins involved in arteriosclerosis.
Carotenoids, such as β-carotene, have been associated with a lower risk of type 2 diabetes, whereas lycopene has been seen to decrease fasting blood glucose levels. Although data on the anti-cancer properties of carotenoids are insufficient, carotenoid consumption is linked to a reduced risk of estrogen receptor-negative breast cancer and prostate cancer.
Previous studies have also reported that the anti-inflammatory properties of lycopene have been associated with a lower risk of various cancers such as lung, breast, prostate, ovarian, and stomach cancers.
The protective properties of carotenoids against ultraviolet radiation have also been examined for the treatment of various eye and skin diseases, and carotenoids have been used in a wide range of cosmeceuticals.
This comprehensive review discussed carotenoids' antioxidant and anti-inflammatory properties, the numerous food sources of carotenoids, and the use of various carotenoids, especially lycopene, as nutritional supplements in treating various diseases. The findings highlight the scope of using carotenoids as nutraceuticals and functional food in treating various diseases and cosmetic treatments.
- Crupi, P., Faienza, M. F., Naeem, M. Y., et al. (2023). Overview of the Potential Beneficial Effects of Carotenoids on Consumer Health and WellBeing. Antioxidants 12(5). doi:10.3390/antiox12051069