Vitamin A is a part of the fat-soluble family of essential vitamins; others in the same family include vitamin K, vitamin E, and vitamin D. Found in a wide variety of foods, including liver, carrots and sweet potatoes.[i] Vitamin A is important for cell differentiation and division, enough growth, and normal growth. It’s necessary for healthy mucous membranes as well as the immune system function.[ii]
Vitamin A deficiency is rare in developed nations, but if it occurs, it causes a weak immune system and bad eyesight. It’s found in both animals and plants. Animal sources like whole milk, meats, liver, fish, egg yolks, and butter contain preformed vitamin A also known as retinol.
Plant sources are commonly referred to as provitamin A carotenoids. These include beta-cryptoxanthin, alpha-carotene, and beta-carotene. The body converts the precursors to form vitamin A that the cells need. Carotenoids can be found in vegetables, orange, yellow and dark green fruits.
Vitamins are essential for good health. Studies have shown that vitamin A is very effective in the prevention and treatment of certain conditions.[iii]
Prevent Bone Fractures
A study published in 2017 found that high dietary ingestion of vitamin A could help maintain healthy bones. The study involved over 300,000 adult participants over 20 years of age. They found that adults with low vitamin A are at high risks of fractures.[iv]
Age-Related Macular Degeneration (AMD)
Obtaining adequate vitamin A helps protect against AMD. Research shows that high amounts of vitamin A in the blood might reduce risks of AMD by 40%.[v]
Reduces Risks Of Specific Cancers
Cancer occurs after abnormal cells start dividing or growing uncontrollably. Since vitamin A plays a significant role in the development and growth of body cells, its notable influence on cancer risks and role in the prevention of cancer is of great interest to scientists. Intake of enough vitamin A from whole plant sources might reduce risks of specific cancer, including bladder cancer, lung cancer, cervical cancer, and Hodgkin’s lymphoma.
Boosts The Immune System
Vitamin A plays a significant role in the maintenance of the body’s natural immune system and the natural defenses as a whole. This includes the mucous barriers in your genitals, gut, lungs, and eyes that help trap bacteria and other harmful agents. Also, it’s involved in the creation and function of the leukocytes that help trap and clear bacteria.
Vitamin A Deficiency
In developing countries, vitamin A deficiency is common, but it’s relatively rare in developed countries like the United States. Night blindness is the earliest sign of vitamin A deficiency. If left unchecked, night blindness can result in permanent blindness. Also, vitamin A deficiency allows opportunistic diseases like pneumonia and measles. Some of the most common deficiencies related to vitamin A include:
Vitamin A is essential for the repair and creation of skin cells. Also, this helps fight inflammation because of particular issues. Failure to get enough vitamin A might lead to eczema and possibly other skin diseases. Eczema is a skin condition that causes inflamed, itchy, and dry skin.
Eye problems are one of the most common issues associated with vitamin A deficiency. In some cases, failure to get sufficient vitamin A may result in dying corneas or complete blindness, often characterized by marks referred to as the Bitot’s spots. Lack of ability to produce tears or dry eyes is one of the signs of vitamin A deficiency.
Lack of vitamin A can ultimately result in night blindness. Some studies, have over the years, reported increased cases of night blindness, specifically in developing nations. Getting enough amounts of vitamin A is very important for eye health. Night blindness and dry eyes are some of the first symptoms of vitamin A deficiency.
Kids who don’t get adequate vitamin A might experience delayed growth. This is because vitamin A is essential for proper body development. A few studies have shown that vitamin A supplements help improve growth.
Chest And Throat Infections
Frequent infections, particularly chest or throat, might be a symptom of vitamin A deficiency. Vitamin A supplements might help with infections to the respiratory tract. Adults having high vitamin A blood levels may experience fewer chest and throat infections.
Possible Side Effects
In a normal dose, vitamin A is 100% safe and doesn’t seem to cause any adverse effects. Nevertheless, large quantities of vitamin A might cause blurry vision, vertigo, vomiting, and nausea.[vi] Moreover, extensive supplementation of large doses, usually 10x the daily recommended intake, can ultimately cause congenital disabilities, pain in bones and joints, skin irritation, nausea, diarrhea, headaches, liver damage, and bone thinning.
Avoid vitamin A supplements if you’re taking any of these medications:
- Targretin (Bexarotene) – Consuming vitamin A alongside this cancer drug might eventually increase the medication’s side effects, including dry and itchy skin.
- Oral retinoids – Taking vitamin A and retinoids might result in lethal vitamin A levels in your blood.
- Hepatotoxic drugs – Consuming vitamin A with medications known to cause liver damage might increase risks of liver disease.
- Anticoagulants – Taking vitamin A might increase the risks of bleeding.
Dosage and Preparation
Vitamin A’s recommended daily intake depends on the type of vitamin A, gender, and age. As mentioned above, the daily recommended intake for adults (19+ years) is 900 mcg and 770 mcg for males and females, respectively.[vii] Basically, vitamin A is available in supplements, usually in the form of (beta carotene, retinyl palmitate, and retinyl acetate) and multivitamins.
High vitamin A doses have been linked with liver problems, lower bone density, and congenital disabilities. People suffering from liver or kidney disease or those that drink heavily should talk to a doctor before taking vitamin A supplements.[viii]
Ways To Get Vitamin A
Most foods contain natural vitamin A. Therefore; it’s obviously easy to get your vitamin A daily-recommended intake from your diet. However, you can take vitamin A supplements to meet the recommended intake.
Natural vitamin A is the nutrient obtained from whole food, while supplements provide isolated vitamin A, usually made artificially. We recommend sticking to natural sources rather than supplements mainly because the food comes with many more benefits, while vitamin A supplements are just vitamin A.
The following foods are the best natural sources of vitamin A.
The liver is a very rich source of vitamin A. One 3 ounce serving of liver contains 6600mcg of vitamin A, which is about 700% more than the recommended daily intake. The liver is an excellent source of vitamin A to the extent that some researchers recommend eating liver-only once a week to avoid taking lots of vitamins.
Dairy is in itself rich in vitamin A. However, in the United States, most types of dairy milk are fortified with more vitamin A. Based on the dairy source, one serving of dairy contains about 100 to 300 mcg of vitamin A.
The skin of one whole sweet potato contains about 1400 mcg of vitamin A. This is over 150% of the daily-recommended intake. For those on a plant-based diet, this makes sweet potatoes a valuable source of vitamin A.
Spinach is widely known as a nutrient superfood for a reason. A ½ cup of spinach contains over 570 mcg of vitamin A. If eaten raw, cooked, or in a smoothie, spinach is an excellent source of vitamin A and fiber.
Like orange fruits, carrots are rich in carotene. One cup of raw proteins contains over 900 mcg of vitamin A.
Vitamin A Supplements
Vitamin A is available in different dietary supplements; often in the form of retinyl or retinyl acetate (preformed vitamin A) and beta-carotene or a combination of provitamin and preformed vitamin A. Vitamin A supplements are usually available in the form of pills.
Common sources of Performed vitamin A include vitamin supplements, fortified foods, and animal products. Technically, carotenoids are naturally found in plant foods. However, other carotenoids are present in foods that aren’t changed to vitamin A but have many health properties, including zeaxanthin, lutein, and lycopene.
What is the main benefit of taking vitamin A?
What food is high in vitamin A?
What does vitamin A do in the body?
In what form is vitamin A best?
Do you need vitamin A supplements?
What does vitamin A prevent?
- [i] Vitamin A. Nutrient lists. USDA Food Composition Database.
- [ii] Boyd K. What is Vitamin A Deficiency? American Academy of Opthalmology. 2019.
- [iii] Gilbert C. What is vitamin A and why do we need it? Community Eye Health. 2013;26(84):65.
- [iv] Zhang X, Zhang R, Moore JB, et al. The Effect of Vitamin A on Fracture Risk: A Meta-Analysis of Cohort Studies. Int J Environ Res Public Health. 2017;14(9). doi:10.3390/ijerph14091043
- [v] Wu J, Cho E, Willett WC, Sastry SM, Schaumberg DA. Intakes of Lutein, Zeaxanthin, and Other Carotenoids and Age-Related Macular Degeneration During 2 Decades of Prospective Follow-up. JAMA Ophthalmol. 2015;133(12):1415-24. doi:10.1001/jamaophthalmol.2015.3590
- [vi] Vitamin A. Mayo Clinic. 2017.
- [vii] Dietary Reference Intakes Tables and Applications. The National Academies of Sciences, Engineering, Medicine.
- [viii] Vitamin A. National Institutes of Health. US Department of Health and Human Services. 2019.