Carotenoids are pigmented compound synthesize by plants and microorganisms. They are usually bright yellow, red, and orange colours in plants, vegetables, and fruits.
Fruits and vegetables constitute the major sources of carotenoid in human diet.
Carotenoids are beneficial to fruit and vegetables by preventing human diseases including cardio-vascular diseases, cancer and other chronic diseases. They are also an important dietary sources of vitamin A.
There are more than 600 different types of carotenoids. Some can be converted into vitamin A when released into the body.
A few of the carotenoids were identified such as alpha carotene, beta carotene, beta cryptoxanthin, lutein, zeaxanthin, lycopene.
Vitamin A is a fat-soluble vitamin. It can be found in many fruits, vegetables, eggs, whole milk, butter, fortified margarine, meat, and oily saltwater fish. Vitamin A helps to form and maintain healthy teeth, skeletal and soft tissue, mucus membranes, and skin.
It is also known as retinol because it produces the pigments in the retina of the eye.
Vitamin A promotes good eyesight, especially in low light
Carotenoids are bioavailable if they are consumed but best absorbed through eating of fat meal. Processing and cooking of food lead to mechanical breakdown of the tissues thereby releasing carotenoids and improves the absorption of food.
They are absorbed into the gastrointestinal mucosalcells and appear unchanged in the circulation and tissues.
In the intestine they are mostly available due to some processing in food such as boiling.
Carotenoids are classified into two main groups: xanthophylls and carotenes. Both types of carotenoids have antioxidant properties. In addition, some carotenoids can be converted into vitamin A, an essential component for human health and growth.
These provitamin A carotenoids include alpha carotene, beta carotene, and beta cryptoxanthin. Non-provitamin A carotenoids include lutein, zeaxanthin, and lycopene.
Xanthophylls
Xanthophylls contain oxygen and sometimes have more of a yellow pigment. Xanthophyll carotenoids can protect one from too much sunlight. They are most associated with eye health. Lutein and zeaxanthin fall under the xanthophyll category. Foods include; kale, spinach, summer squash, pumpkin, avocado, yellow-fleshed fruits, corn and egg yolks.
Carotenes
Carotenes which are purely hydrocarbons does not contain oxygen and are associated with more of an orange pigment. Carotene carotenoids play a significant role in helping plants grow. Beta carotene and lycopene fall under this category of carotenoids.
Foods in the carotene include carrots, cantaloupe, sweet potatoes, papaya, pumpkin, tangerines, tomatoes, winter squash
Alpha-carotene and βeta-carotene are primarily regarded as precursors of vitamin A. Common orange, yellow, and green-colored fruits and vegetables such as carrot, pumpkin, apricot, sweet potato, and beans are rich sources of these carotenoids. The conversion β-carotene to vitamin A (retinol) is theoretically higher than α-carotene and β-cryptoxanthin.
For instance, one mole of β-carotene yields two moles of retinol, while the other two provitamin A carotenoids are only half as active as β-carotene.
Beta carotene has said to have reduce vitamin deficiency in human.
Foods that are rich in beta-cryptoxanthin include tangerines, persimmons and oranges.
Beta-cryptoxanthin
Beta-cryptoxanthin is more of a vitamin A-forming because research shown that it has a higher bioavailability than alpha and beta-carotene.
Foods rich in lutein include egg yolks, broccoli, spinach, kale, corn, orange pepper, kiwi fruit, grapes, orange juice, zucchini, and squash.
Lutein is absorbed best when it is taken with a high-fat meal. lutein and zeaxanthin, they are also present in high concentrations in egg yolks. Lutein and zeaxanthin are carotenoid pigments that impart yellow or orange color to various common foods such as cantaloupe, pasta, corn, carrots, orange/yellow peppers, fish, salmon and eggs.
Health benefits of carotenoids include essential growth, immune system and eye health.
Eating carotenoid-rich foods can protect the eye and prevent the growth of cancerous cells.
One of the leading causes of blindness is macular degeneration, or the degeneration of the center of the retina. Long-term blue light exposure can cause this and negatively affect the delicate parts of the eye.
However, the carotenoids lutein and zeaxanthin found in the retina can help to absorb blue light.
Carotenoids have been associated with lowering cancer risk, specifically lung cancer. When you smoke cigarettes, you ingest harmful chemicals that destroy healthy cells. Lycopene has reported to have reduced postrate cancer. Similarly, carotenoids have been associated with reducing the risk of skin cancer.
Some carotenoids can break down into vitamin A, a nutrient that protects against premature skin damage from sun exposure. Both are risks for melanoma, premature wrinkles, and unhealthy skin.
A 2015 review found that foods high in carotenoids appear to be protective against head and neck cancers
Adding more carotenoid-rich foods to diet strengthen immune system and overall health. While carotenoids are available in vitamin A supplements, consuming them naturally enhances their antioxidant effects.
In addition, supplements can be dangerous if they contain high levels of vitamin A, which can be toxic if you take too much.
Carotenoids is an essential source of vitamin A, the alpha carotene, beta carotene and beta cryptoxantin are pro vitamins that can be converted to retinol. They are varied in their conversion and essential.
Thanks for reading!
Article By:
Faizah Jumoke Abdulhameed
Food, Nutrients & Health
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References
2. A.V. Rao a,∗, L.G. Rao b (2007). Carotenoids and human health. Pharmacological Research 55 (2007) 207–216
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