Vitamin A Usage, Benefits and Food Sources

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.

Health Benefits

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.

๐Ÿ‘จ Man Nutritional Needs

  • 1 โ€“ 3 years: 300 mcg per day
  • 4 โ€“ 8 years: 400 mcg per day
  • 9 โ€“ 13 years: 600 mcg per day
  • 14-18 years: 900 mcg per day
  • 19+ years: 900 mcg per day

๐Ÿ‘ฉ Woman Nutritional Needs

  • 1 โ€“ 3 years: 300 mcg per day
  • 4 โ€“ 8 years: 400 mcg per day
  • 9 โ€“ 13 years: 600 mcg per day
  • 14-18 years: 700 mcg per day
  • 19+ years: 770 mcg per day

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:

Dry Skin

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.

Dry Eyes

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.

Night Blindness

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.

Stunted Growth

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.

Interactions

Avoid vitamin A supplements if you’re taking any of these medications:

  • Targretin (Bexarotene) โ€“ Consuming vitamin A alongside this cancer drug might eventually increase the medication’s side effects, including dry and itchy skin.
  • Oral retinoids โ€“ Taking vitamin A and retinoids might result in lethal vitamin A levels in your blood.
  • Hepatotoxic drugs โ€“ Consuming vitamin A with medications known to cause liver damage might increase risks of liver disease.
  • Anticoagulants โ€“ 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.


Foods

The following foods are the best natural sources of vitamin A.

Liver

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

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.

Sweet Potato

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

Spinach is widely known as a nutrient superfood for a reason. A ยฝ 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.

Carrots

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.

FAQs

What is the main benefit of taking vitamin A?

Vitamin A is essential for reproduction, the immune system, and normal vision. Also, vitamin A helps the kidneys, lungs, and heart to make the organs work properly.

What food is high in vitamin A?

In the United States, foods rich in vitamin A include fortified cereals, fish, liver, and dairy products. On the other hand, the best sources of provitamin A are squash, cantaloupe, broccoli, and carrots.

What does vitamin A do in the body?

Vitamin A is an essential fat-soluble vitamin that's present in many foods. It's essential for reproduction, the immune system, and normal vision.

In what form is vitamin A best?

Beta-carotene is the most popular carotenoid. Carotenoids' potential to produce vitamin A in a human body is usually expressed as RAE (Retinol Activity Equivalents).

Do you need vitamin A supplements?

You shouldn't take large doses of vitamin A unless recommended by a health physician. This is because large amounts of vitamin A have been associated with liver problems, lower bone density, and congenital disabilities. Also, heavy drinkers should avoid taking vitamin A supplements without a doctor's recommendation.

What does vitamin A prevent?

Vitamin A is known to prevent different types of acne and cancer. Also, it might help in treating psoriasis. Also, it has been shown to treat wrinkled or dry skin. Also, it helps protect against respiratory tract infections.

 

Sources

  1. [i] Vitamin A. Nutrient lists. USDA Food Composition Database.
  2. [ii] Boyd K. What is Vitamin A Deficiency? American Academy of Opthalmology. 2019.
  3. [iii] Gilbert C. What is vitamin A and why do we need it? Community Eye Health. 2013;26(84):65.
  4. [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
  5. [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
  6. [vi] Vitamin A. Mayo Clinic. 2017.
  7. [vii] Dietary Reference Intakes Tables and Applications. The National Academies of Sciences, Engineering, Medicine.
  8. [viii] Vitamin A. National Institutes of Health. US Department of Health and Human Services. 2019.