What is Vitamin A and what does it do in the body?
Vitamin A was the first vitamin to be discovered, hence why it got its name of Vitamin A. It is a fat-soluble vitamin that is mainly known for its function in vision, which is why many people say to eat carrots for your eye health. Rhodopsin is the pigment that enables the rods in the retina to detect light and this pigment cannot be made without retinol, known as preformed Vitamin A. Vitamin A is mainly stored in the liver, but it is also stored in the eyes, kidneys, lungs, and fat tissue. The body needs Zinc to help release stores of vitamin A for use; see the monograph on Zinc for more information on that important mineral.
Vitamin A performs many important functions in the body, some of the main ones include vision, growth, healing, skin health, antioxidant action, and supporting immune function. As discussed above, retinol is needed for the formation of rhodopsin, which is needed for light vision. Lack of vitamin A can lead to night blindness because of this function. Vitamin A also helps with the health of the cornea and eye covering, so deficiency may allow irritation and inflammation of eye tissue to occur more easily. Vitamin A is involved in laying down new cells; it is needed after tissue injury or surgery, it is needed for the repair of tissues, and to help protect tissues from infection.
Vitamin A ensures healthy skin, both exterior skin and interior skin, meaning the mucous membrane linings of the nose, eyes, intestinal tract, respiratory lining, and bladder. Vitamin A promotes the health of the mucous membrane range linings of the intestinal tract, which may help prevent leaky gut. For more information formation on what can support the body with leaky gut, check out our blog post: Digestion 101- Physio and Pathophysiology- Part III. It stimulates the growth of the base layer of the skin as well as helps the cells differentiate normally and keep their structural integrity; by helping with normal differentiation, Vitamin A helps to protect these areas from cancer development as well. Vitamin A helps neutralize free radicals; beta-carotene protects the tissues from the toxic singlet oxygen radical. This function helps to protect the body from smoke and other pollutants and may prevent problems such as ulcers and atherosclerosis. Vitamin A also supports the activity of the immune system by optimizing white blood cell function, enhancing the recognition of food antigens, and blocks the activity of certain viruses.
What are some causes of Vitamin A deficiency?
Some of the causes of Vitamin A deficiency include alcohol use, vitamin E deficiency, cortisone medication, excessive iron intake, and lack of dietary intake. Alcohol not only reduces the absorption of Vitamin A to cause deficiency, it also depletes liver storage of Vitamin A. Storage of Vitamin A is also decreased during times of stress or illness unless its intake is increased. Another cause of deficiency is impaired absorption of fat-soluble vitamins, which is discussed more in-depth in the blog post: Digestion 101-Physio and Pathophysiology-Part II.
Approximately 25% of Americans get less than half of the recommended RDA for vitamin A, around 3,000 IU, in their diets mainly due to those who do not eat carotene-containing fruits and vegetables or those who eat many processed foods, which are lacking in vitamins. Around 10,000 IU of beta-carotene will convert to approximately 3,000 IU of Vitamin A in the body; around 2 medium sized carrots yields that amount of beta-carotene.
Vitamin A deficiency can lead to night blindness, increased cancer risk, harder and drier skin, blemishes, acne, boils, dandruff, and decreased immune function.
What is Vitamin A used for?
Vitamin A is used for conditions of the eyes, skin, infections, and may be useful in cancer prevention. Vitamin A can be useful during infection because it protects the tissues during infections and promotes rapid recovery through supporting the health of the skin and mucous membranes, stimulating mucous production, and by improving antibody response and white blood cell function.
For the eyes, vitamin A may be helpful in the treatment of conjunctivitis, blurred vision, nearsightedness, cataracts, and glaucoma. For the skin, vitamin A may be helpful for rashes, boils, and skin ulcers. It can be useful before and after surgery to promote healing. It may be helpful for acne as well. Due to its role in maintaining the cell integrity of the skin and mucous membranes, and by supporting proper cell differentiation, Vitamin A may be useful in cancer prevention. Vitamin A may also be useful for asthma, fibrocystic breast disease, plantar warts, sebaceous cysts, ulcers, and premenstrual syndrome.
Vitamin A may also be useful in the treatment of leaky gut. Vitamin A may help prevent leaky gut; one study showed that lower serum retinol was associated with leaky gut (Abdelhamid & Luo, 2018). Vitamin A may also support leaky gut by supporting the mucous membranes that seal the gut wall, and by supporting a healthy gut microbiome. For a more in-depth explanation of leaky gut see the blog post: Digestion 101-Physio and Pathophysiology-Part III.
What are the available forms of Vitamin A?
As mentioned above, the original discovery of vitamin A focused on preformed Vitamin A, or retinol. The other category within Vitamin A is provitamin A, which are substances belonging to the carotenoid family that can be converted into retinol. The most studied of the provitamin A carotenoids are alpha-carotene, beta-cryptoxanthin, and beta-carotene. People with diabetes and low thyroid activity have lowered ability to convert beta-carotene to Vitamin A.
Some of our options for Vitamin A include:
Micellized Vitamin A SFI Health- this is a form of Vitamin A that is easily absorbed because it is made to have a hydrophilic head and hydrophobic tail.
Two options for Vitamin A in its preformed form from a cod liver oil source are Vitamin A Vital Nutrients and Vitamin A Pure.
For beta-carotene in supplement form, try Beta-Carotene Pure. Cataplex A Standard Process is another supplement with provitamin A as Beta-carotene.
For a formula that includes Vitamin A that can be supportive for the eyes, specifically the macula we also have Macular Support Formula Pure.
What are food sources of Vitamin A?
Retinol (preformed Vitamin A) is the main source of vitamin A from animal sources. It is found in high concentrations in egg yolks, milk, cream, butter, meat, and fish. Provitamin A is mainly found in food as beta-carotene; beta-carotene is found in leafy and green vegetables including asparagus, broccoli, kale, and spinach, carrots, pumpkin, red cabbage, sweet potatoes, apricots, cantaloupe, cherries, mango, and peaches.
What are contraindications of Vitamin A?
Pregnant women should ensure not to take too much Vitamin A; it is suggested that they limit their vitamin A intake to 10,000 IU daily with no more than 5,000 IU from supplements.
Possible interactions include: hepatotoxic medicines, Orlistat (Alli, Xenical), retinoids, and warfarin.
What are the side effects of taking Vitamin A?
Eating too much beta-carotene can lead to an orange-yellow discoloring of the skin called carotenodermia. Too much preformed vitamin A can lead to slight swelling of the brain, nausea, vomiting, irritability, dizziness, abdominal pain, hair loss, anorexia, liver enlargement, menstrual problems, and bone abnormalities.
High doses of vitamin A may increase the risk of osteoporosis and hip fracture, especially in older adults and postmenopausal women.
In children, high doses of vitamin A may cause growth problems, drowsiness, vision problems, fever, chills, cough with mucus, chest pain, trouble breathing, vomiting, diarrhea, and peeling skin.
Lower quantities of vitamin A are needed when taking vitamins C and E as well because these vitamins prevent the loss of stored vitamin A.
References
Abdelhamid, L., & Luo, X. M. (2018). Retinoic Acid, Leaky Gut, and Autoimmune Diseases. Nutrients, 10(8), 1016. https://doi.org/10.3390/nu10081016
Drugs.com. (2025). Vitamin A. Drugs.com.https://www.drugs.com/mtm/vitamin-a.html
Haas, E.M. (2006). Staying Healthy with Nutrition: The Complete Guide to Diet and Nutritional Medicine: 21st Edition. Ten Speed Press.
Mansfield, Todd. (2018, Dec 5). Vitamin A, Leaky Gut and the Immune System. Byron Herbalist. https://www.byronherbalist.com.au/gut-health/vitamin-a-leaky-gut/
Mayo Clinic Staff. (2025). Vitamin A. MayoClinic. https://www.mayoclinic.org/drugs-supplements-vitamin-a/art-20365945
