Vitamin A is the name of a group of fat-soluble retinoids, primarily retinol and retinyl esters . Vitamin A is involved in immune function, cellular communication, growth and development, and male and female reproduction . Vitamin A supports cell growth and differentiation, playing a critical role in the normal formation and maintenance of the heart, lungs, eyes, and other organs . Vitamin A is also critical for vision as an essential component of rhodopsin, the light-sensitive protein in the retina that responds to light entering the eye, and because it supports the normal differentiation and functioning of the conjunctival membranes and cornea .
Vitamin A is an important nutrient that benefits health in many ways.
Provitamin A carotenoids such as beta carotene, alpha carotene, and beta cryptoxanthin are precursors of vitamin A and have antioxidant properties.
Carotenoids protect your body from free radicals — highly reactive molecules that can harm your body by creating oxidative stress .
Diets high in carotenoids are associated with a lower risk of many of these conditions, such as heart disease, lung cancer, and diabetes .
Essential for eye health and preventing macular degeneration
As mentioned above, vitamin A is essential to vision and eye health.
Adequate dietary intake of vitamin A helps protect against certain eye diseases, such as age-related macular degeneration (AMD).
Studies show that higher blood levels of beta carotene, alpha carotene, and beta cryptoxanthin may reduce your risk of AMD by up to 25% .
This risk reduction is linked to carotenoid nutrients’ protection of macular tissue by lowering levels of oxidative stress.
May protect against certain cancers
Due to their antioxidant properties, carotenoid-rich fruits and vegetables may protect against certain types of cancer.
For example, a study in more than 10,000 adults found that smokers with the highest blood levels of alpha carotene and beta cryptoxanthin had a 46% and 61% lower risk of dying from lung cancer, respectively, than nonsmokers with the lowest intake of these nutrients .
What’s more, test-tube studies demonstrate that retinoids may inhibit the growth of certain cancer cells, such as bladder, breast, and ovarian cancer cells .
Vital for fertility and fetal development
Vitamin A is essential for both male and female reproduction because it plays a role in sperm and egg development.
It’s also critical for placental health, fetal tissue development and maintenance, and fetal growth .
Therefore, vitamin A is integral to the health of pregnant people and their developing babies, as well as people who are trying to become pregnant.
Boosts your immune system
Vitamin A impacts immune health by stimulating responses that protect your body from illnesses and infections.
Vitamin A is involved in the creation of certain cells, including B cells and T cells, which play central roles in immune responses that guard against disease.
A deficiency in this nutrient leads to increased levels of pro-inflammatory molecules that diminish immune system response and function.
Though vitamin A deficiency is rare in developed countries such as the United States, it’s common in developing countries, where populations may have limited access to food sources of preformed vitamin A and provitamin A carotenoids.
Vitamin A deficiency can lead to severe health complications.
According to the World Health Organization, vitamin A deficiency is the leading cause of preventable blindness in children worldwide .
Vitamin A deficiency also increases the severity and risk of dying from infections like measles and diarrhea .
Additionally, research has found that vitamin A deficiency raises the risk of anemia and death in pregnant women and negatively impacts the fetus by slowing growth and development.
Less severe symptoms of vitamin A deficiency include skin issues such as hyperkeratosis and acne.
Certain groups — such as premature infants, people with cystic fibrosis, and pregnant or breastfeeding people in developing countries — are more at risk of vitamin A deficiency .
Vitamin A deficiency can lead to blindness, increased infection risk, pregnancy complications, and skin issues.
There are many dietary sources of both preformed vitamin A and provitamin A carotenoids.
Preformed vitamin A is more readily absorbed and utilized by your body than plant-based sources of provitamin A carotenoids.
Your body’s ability to effectively convert carotenoids, such as beta carotene, into active vitamin A depends on many factors — including genetics, diet, overall health, and medications.
For this reason, those who follow plant-based diets — especially vegans — should be vigilant about getting enough carotenoid-rich foods.
Foods highest in preformed vitamin A include:
- egg yolks
- beef liver
- cod liver oil
- chicken liver
- cheddar cheese
- liver sausage
- king mackerel
Foods high in provitamin A carotenoids like beta carotene include :
- sweet potatoes
- dandelion greens
- collard greens
- winter squash
- red peppers