7 Vital Benefits of Vitamin A and How to Get the Right Amount

Besides being touted for good vision, vitamin A may get slightly less fanfare than other "star" vitamins.

Popularity aside, it's just as important for your body. There are several vitamin A benefits, and the nutrient plays crucial behind-the-scenes roles for your health beyond keeping your vision sharp — from supporting your immune sustem to promoting growth and reproduction.

But vitamin A's benefits seem to be dependent on getting the right amount of this antioxidant: Too little or too much vitamin A can be harmful to your health.

Vitamin A is a fat-soluble vitamin that's stored in your liver.

It helps to protect your eyesight (especially your night vision) and aids in healthy pregnancy and breastfeeding. It also helps maintain several parts of your body, including your teeth, skeletal and soft tissue, mucus membranes and skin, per the U.S. National Library of Medicine.

You'll find vitamin A in two forms:

• ​Retinol:​ This is an active form of vitamin A that's found in whole milk, animal liver and some fortified foods. It's called "retinol" because it produces the pigments in the eye's retina.

• ​Carotenoids:​ These pigments are found in plant foods and can transform into an active form of vitamin A. One common carotenoid is beta-carotene, but scientists have identified more than 500 carotenoids.

Two more terms to keep in mind: The vitamin A found in animal products like meat and dairy foods is called ​preformed vitamin A​. The kind found in plant-based foods like fruits and vegetables is called ​provitamin A​.

Several dietary supplements provide vitamin A in either form or in a combination of both.

Your age and sex will determine the amount of vitamin A you need, and pregnant or breastfeeding women may need more than others.

Here's how much vitamin A (in micrograms) you should aim to get daily, per the National Institutes of Health (NIH).

Vitamin A is found in a variety of healthy and delicious foods. According to the USDA, the foods highest in vitamin A per common serving are:

• ​Cooked lamb liver​ (3 oz): 735% DV
• ​Pan-fried beef liver​ (1 slice): 697%
• ​Boiled sweet potatoes​ (1 cup, mashed): 287% DV
• ​Canned pumpkin​ (1 cup): 212% DV
• ​Cooked eel​ (1 fillet): 201% DV
• ​Cod liver oil​ (1 tsp): 150% DV
• ​Cooked carrots​ (1 cup, sliced): 148% DV
• ​Cooked bluefin tuna​ (6 oz fillet): 143% DV
• ​Cooked butternut squash​ (1 cup, cubes): 127% DV
• ​Cooked spinach​ (1 cup): 105% DV

Other solid sources of vitamin A include Swiss chard, mustard greens, collards, cantaloupe and milk.

One of the most notable benefits of vitamin A is that it can help protect your vision, particularly in the dark.

Your eye needs to produce certain pigments for proper function of your retina, which allows you to see the full spectrum of light — but without vitamin A, this pigment production comes to a halt, per the American Academy of Ophthalmology (AAO).

This can lead to night blindness (nyctalopia), which is poor vision in low lighting or at night. In fact, night blindness is typically a symptom of an underlying retina problem, and not a disease in and of itself, per the Cleveland Clinic.

Such vision changes can often be treated: For instance, supplementing with vitamin A over 18 months was found to significantly improve night vision in a July 2013 case report in the ​Journal of Optometry​.

"Ophthalmic complications of vitamin A deficiency tend to be reversible with adequate treatment," note the researchers. "In particular, vitamin A deficiency should be prominent in the differential diagnosis of night blindness, which can be confirmed or refuted with a simple blood test."

Vitamin A benefits also include nourishing parts of the eye such as the cornea (which focuses light into the eye) and lubrication. The eyes need vitamin A to produce adequate moisture, according to the AAO.

Originally, beta-carotene was included in a mix of ingredients (along with vitamins C and E, plus zinc) that's linked to a 25-percent reduction in the risk of the progression of age-related macular degeneration in the widely-cited Age-Related Eye Disease Study (AREDS).

FYI, age-related macular degeneration is the leading cause of vision loss in people 50 and older, and causes a loss in central vision, making it more difficult to see faces, drive or do close-up work, per the National Eye Institute.

However, a follow-up May 2013 AREDS2 study published in ​JAMA​ found that beta-carotene was not a required ingredient in the original AREDS formulation.

What's more, taking beta-carotene supplements does not appear to prevent or delay the onset of age-related macular degeneration, per a July 2017 study in the ​Cochrane Database of Systematic Reviews​.

By eating a diet rich in vitamin A, you may be able to better ward off infections.

"Vitamin A is involved in regulating the immune system," says Keith Ayoob, RD, associate clinical professor emeritus at Albert Einstein College of Medicine.

"It can also help protect you from infections that enter the body through the skin, as well as the tissues in the mouth, gut and urinary tract. Those tissues, if healthy, help form a barrier to infections."

Essentially, vitamin A provides double protection for your immune system. That's because it contributes to both innate and adaptive immunity, per Oregon State University.

• ​Innate immunity​ involves the skin and mucosal cells of the eye and respiratory, gastrointestinal and genitourinary tracts providing a barrier against infection. Vitamin A helps by protecting the functional and structural integrity of mucosal cells, and also plays an important role in the normal function of several immune cells needed for this response.

• ​Adaptive immunity​ involves specific cells protecting the body from antigens. Vitamin A is needed for the proper function of cells that play a role in adaptive immunity, such as T and B lymphocytes, making it necessary for the generation of antibody responses.

However, too much vitamin A can hamper the body's acquired immunity and create the opportunity for infections that you would otherwise be immune to, per a May 2015 study in the ​Journal of Leukocyte Biology​​.​

That's one reason it's important to speak to your healthcare provider before seeking out vitamin A supplements.

The carotenoid beta-carotene (which turns into vitamin A in the body) is an antioxidant and therefore can help ward off cell damage caused by \ free radicals, per the U.S. National Library of Medicine.

"It's one of many in a class of carotenoids that emerging evidence suggests may help delay some diseases of aging, like declining immune function," Ayoob says.

Everyday factors like digestion, radiation or tobacco smoke cause the formation of free radicals, according to the Mayo Clinic.

These free radicals are also believed to contribute to certain long-term diseases, per the U.S. National Library of Medicine. Eating foods rich in beta-carotene is linked to reducing cancer risk, but supplements do not appear to have the same effect.

Another important vitamin A benefit is that it's part of the reproductive process, enabling the growth of sperm and eventually the growth of a baby.

During pregnancy, vitamin A helps the placenta form, and also allows the growth and maintenance of epithelial tissues (such as mucous membranes, the lining of the gastrointestinal tract, bladder, lungs, urinary tract, vagina, skin and cornea) and bones and teeth, per the University of Rochester Medical Center.

High doses of vitamin A and synthetic retinols might lead to growth problems in the womb and birth defects. That said, you need about 10 to 20 percent more vitamin A when you're pregnant, which is why it's available in many prenatal formulations, per a March 2019 review in the journal ​Nutrients​​.​

"In places where vitamin A deficiency (VAD) is rare, the recommendation is for caution with regard to excess dosing, with vitamin A supplementation or even the ingestion of foods such as liver that are rich in vitamin A being contraindicated," note the researchers.

If you're pregnant, talk to your doctor about your diet and adequate vitamin intake before taking any supplements.

One of many potential vitamin A benefits is that it may lower your risk of certain types of cancer, although more research is needed to fully determine the association.

Getting enough vitamin A in the diet is tied to a 17-percent reduced chance of getting cutaneous squamous cell carcinoma, a common type of skin cancer among those with fair skin, in a July 2019 study in the journal ​JAMA Dermatology​​.​

People in the highest category for vitamin A intake ate on average the amount of vitamin A that you'd find in one medium baked potato or two large carrots per day.

Other research complicates the link between vitamin A and cancer risk: While current and former smokers who have higher intakes of carotenoids, fruits and vegetables or both may have a lower risk of lung cancer, it's unknown if supplemental beta-carotene or vitamin A can help prevent the disease, per the NIH.

In fact, some studies have shown an increase in lung cancer risk among those who take beta-carotene supplements.

What's more, men who took daily supplements of beta-carotene and retinyl palmitate (composed of vitamin A) were observed to have a 35-percent lower risk of nonaggressive prostate cancer than those who did not in a 2009 study in the journal ​Cancer Epidemiology, Biomarkers & Prevention​​.​

However, men who had the highest baseline blood retinol (vitamin A) levels were observed to be 20 percent more likely to develop prostate cancer than those who had the lowest levels in an April 2011 study in the ​American Journal of Epidemiology​​.​

More research is needed to determine how vitamin A intake — both through food sources and supplements — may affect risk and outcomes of certain cancers.

Vitamin A plays an important role in the growth of bones and teeth, per the University of Rochester Medical Center.

Striking the right balance of vitamin A seems to be key when it comes to preventing fractures later in life, but more studies are needed to confirm this.

Lower blood level of retinol was tied to slightly increased total fracture risk and hip fracture risk in a September 2017 meta-analysis in the ​International Journal of Environmental Research and Public Health​​.​

However, the study also found that higher dietary intake of retinol and total vitamin A may be linked to slightly decreasing total fracture risk while ​increasing​ hip fracture risk.

The data suggest that the levels of vitamin A may differentially influence the risks of total and hip fractures, but clinical trials are needed to confirm the results, note the researchers.

Other research has found that high intakes of preformed vitamin A are associated with reduced bone mineral density and increased fracture risk, but because study results have been mixed, the exact intake level for this association to occur is unknown, per the NIH.

There are some links between vitamin A and an improvement in acne.

When 50 patients with moderate acne were treated with low-dose isotretinoin (synthetic vitamin A) tablets for three months, positive improvements were found in 90.8 percent of patients ages 12 to 20 and in 89.6 percent of patients ages 21 to 35, per a small February 2015 study in the journal ​Medical Archives​​.​

Inadequate vitamin A can result in hyperkeratinization, an excess of keratin that leads to clogged hair follicles, per a 2015 article in the ​Journal of Nutrition & Food Sciences​.

Although Vitamin A deficiency is rare in Western countries, it can still occur.

Certain underlying conditions that affect normal digestion can cause malabsorption of vitamin A — for instance, celiac disease, Crohn's disease, cirrhosis or cystic fibrosis, per the Harvard T.H. Chan School of Public Health.

Symptoms of vitamin A deficiency may include:

• Fatigue
• Susceptibility to infections
• Severe dryness of the eye (xerophthalmia)
• Night blindness
• Irregular patches on the white of eyes
• Dry skin or hair
• Infertility

In more than half of all countries, especially in Southeast Asia and Africa, vitamin A deficiency is a public health problem and affects young children and pregnant women in low-income areas the hardest.

Inadequate vitamin A is linked to a high risk of disease and death, per the World Health Organization (WHO).

In children, a vitamin A deficiency causes severe visual impairment and even blindness.

It also greatly heightens the risk of severe illness or death from common childhood infections such as measles, per the WHO.

Approximately 250 million preschool children are deficient in vitamin A. What's more, it's believed that up to 500,000 children with vitamin A deficiencies go blind every year.

In high-risk areas, vitamin A deficiency occurs in pregnant women particularly during their last trimester, per the WHO.

This is when their vitamin A needs and those of their unborn child are the greatest. As a result, there is a high prevalence of night blindness during this time period.

Operations like bariatric surgery or bowel resection surgery can lead to a malabsorption of vitamin A.

Deficiencies may be on the rise in the developed world due to the popularity of bariatric surgery, per a July 2013 case report in the ​Journal of Optometry​.

In the United States, vitamin A toxicity may actually be more common than vitamin A deficiency due to the large doses of preformed vitamin A (retinol) in some supplements, per the Harvard T.H. Chan School of Public Health.

Because it's fat-soluble, vitamin A that is not used by the body right away gets absorbed and stored in either the liver or fat tissue. Too much vitamin A storage can become toxic, and can also hamper the benefits of vitamin D.

That said, beta-carotene is not toxic at high levels, because the body can form vitamin A from it as needed.

Signs of vitamin A toxicity include:

• Vision changes like blurry sight
• Sensitivity to bright light
• Bone pain
• Dry skin
• Nausea and vomiting

There are several potential drug interactions that may occur when you take vitamin A supplements, per the Mayo Clinic:

Using vitamin A supplements while taking anticoagulants (used to prevent blood clots) could increase your risk of bleeding.

Using this topical cancer drug with vitamin A supplements raises the risk of side effects from the drug, including dry and itchy skin.

High doses of vitamin A can result in liver damage, and combining large doses with other drugs, such as acetaminophen, that may damage the liver could increase liver disease risk.

Your doctor may recommend that you take a multivitamin with beta-carotene and vitamin A if you take this weight-loss drug, since it can decrease the absorption of vitamin A from food sources.

You shouldn't take these oral prescription drugs at the same time as vitamin A supplements, because it could spike your vitamin A blood levels to dangerously high levels.

Talk to your doctor about vitamin A supplements before you start taking vitamin A supplements.

Vitamin A supplements mostly show benefits for those who have a limited or poor diet, or who have a greater need for vitamin A due to conditions like pancreatic disease, eye disease or measles, per the Mayo Clinic.

Supplements might also not provide the same antioxidant properties that you would naturally get via food.

Remember, vitamin A toxicity may be more common in the United States than deficiency, so it's quite possible you don't need a supplement to reach your recommended daily value.