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If you have any medical questions or concerns, please talk to your healthcare provider. The articles on Health Guide are underpinned by peer-reviewed research and information drawn from medical societies and governmental agencies. However, they are not a substitute for professional medical advice, diagnosis, or treatment.
On the inside of your eyes are millions of cells called rods. While these cells have a simple name, they are critically important in your vision. Specifically, rods support your ability to see in the dark and to adapt to changes in lighting. But what does this have to do with vitamin A?
Well, vitamin A (otherwise known as retinol) is a precursor to a vital protein—called rhodopsin— that’s found in these rods. Without vitamin A, we wouldn’t be able to develop these rods at all. So, vitamin A is pretty important. Besides eye health, vitamin A is an essential vitamin important to your skin and your immune system. It has also been commonly described as an antioxidant against potentially harmful free radicals (Chea, 2020).
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What is the difference between retinyl palmitate and vitamin A?
Vitamin A palmitate, otherwise known as retinyl palmitate, is a pre-formed version of vitamin A. It’s found in animal products like eggs or chicken and beef liver. Vitamin A is also often added to dairy products like milk (Chea, 2020). But it can also be found in supplements on the shelves of drug stores.
Vitamin A can be categorized into two types of dietary nutrients: retinoids and carotenoids. You can get both from a healthy diet of various fruits, vegetables, and protein (NIH, 2020).
- Retinoids (which include vitamin A palmitate) are bioavailable forms of vitamin A, which means they do not need to be converted in the same way as beta carotene after ingestion (NIH, 2020). There is also some research that suggests topical forms of retinoids could be useful in dermatology (Riahi, 2016).
- Carotenoids (like beta carotene) are pigments that are found in fruits and vegetables. These nutrients get converted to vitamin A after you eat them (NIH, 2020).
Are there benefits to supplementing with vitamin A?
We’ve touched on some potential benefits of vitamin A for eye health, skin, and the immune system, but let’s look at those and other benefits a bit more closely.
Due to the well-documented importance of vitamin A on human health, researchers since the 1980s have tried to study if taking vitamin A (usually in combination with other vitamins) can prevent cancer, heart disease, or specific conditions of the eye.
Most of these trials did not show promising results, except in particular cases like a condition of the eye called age-related macular degeneration.
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Here’s a summary of a few of the studies:
- ATBC trial: This trial reported no significant benefit in the rate of prostate cancer and the risk of lung cancer in male smokers between the ages of 50 and 69 who took alpha-tocopherol (vitamin E) and beta carotene supplements (ATBC cancer prevention study group, 1994).
- AREDS & AREDS2 studies: People who took a blend of supplements (beta carotene, vitamin E, vitamin C, zinc, and copper) were reported to have a lower risk of developing advanced age-related macular degeneration by 25%. Although this did not prevent the disease’s symptoms, it seemed to slow down the progression of blurry vision and blindness (AREDS research group, 2001). But roughly a decade later, findings were less promising. In the AREDS2 follow-up trial, researchers revealed that beta carotene did not play a role in preventing the disease and it was subsequently removed from the AREDS formula (AREDS2 research group, 2013).
Because of the lack of documented benefit of supplemental vitamin A or its derivatives in people without a deficiency, the United States Preventative Services Task Force (USPSTF) explicitly recommends against using beta carotene to prevent cardiovascular disease or cancer (Moyer, 2014).
Although dietary supplements that contain retinyl palmitate are available, they come with a disclaimer that they are not FDA approved to treat or prevent disease. They’re only recommended in cases of a known vitamin A deficiency.
What risks are possible from taking vitamin A?
Vitamin A taken by a pregnant woman can have severe developmental effects on the baby. Healthcare providers only recommend vitamin A supplementation in pregnant women if they are known to be deficient, so be sure to speak with your provider if you are pregnant and vitamin A is in a supplement you take (Chea, 2020)
Taking too much vitamin A can lead to a few side effects. While these risks are uncommon, they can happen when people take too many supplements. Make sure you know how much and what form of vitamin A you are taking, and be sure to check your multivitamins, too.
Because retinyl palmitate is a fat-soluble vitamin, it can build up in your liver, leading to side effects. If you have liver or kidney disease, taking a supplement containing vitamin A might not be right for you (Chea, 2020).
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Taking too much vitamin A consistently can lead to (Chea, 2020):
- Bodily aches and pains
- Nausea and vomiting
Vitamin A-containing products can also interact with other medications you take, so talk to your healthcare provider before starting any vitamin or supplement.
- Age-Related Eye Disease Study Research Group (2001). A randomized, placebo-controlled, clinical trial of high-dose supplementation with vitamins C and E, beta carotene, and zinc for age-related macular degeneration and vision loss: AREDS report no. 8. Archives of Ophthalmology (Chicago, Ill.: 1960), 119(10), 1417–1436. doi: 10.1001/archopht.119.10.1417. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1462955/
- Age-Related Eye Disease Study 2 Research Group (2013). Lutein + zeaxanthin and omega-3 fatty acids for age-related macular degeneration: the Age-Related Eye Disease Study 2 (AREDS2) randomized clinical trial. JAMA, 309(19), 2005–2015. doi: 10.1001/jama.2013.4997. Retrieved from https://pubmed.ncbi.nlm.nih.gov/23644932/
- Chea, E. P., Lopez, M. J., & Milstein, H. (2020). Vitamin A. In StatPearls. StatPearls Publishing. Retrieved from https://pubmed.ncbi.nlm.nih.gov/29493984/
- de Carvalho Melo-Cavalcante, A. A., da Rocha Sousa, L., Alencar, M., de Oliveira Santos, J. V., & da Mata, A., et al. (2019). Retinol palmitate and ascorbic acid: Role in oncological prevention and therapy. Biomedicine & Pharmacotherapy = Biomedecine & Pharmacotherapie, 109, 1394–1405. doi: 10.1016/j.biopha.2018.10.115. Retrieved from https://pubmed.ncbi.nlm.nih.gov/30551390/
- Imdad, A., Mayo-Wilson, E., Herzer, K., & Bhutta, Z. A. (2017). Vitamin A supplementation for preventing morbidity and mortality in children from six months to five years of age. The Cochrane Database of Systematic Reviews, 3(3), CD008524. doi: 10.1002/14651858.CD008524.pub3. Retrieved from https://pubmed.ncbi.nlm.nih.gov/28282701/
- Moyer, V. A., & U.S. Preventive Services Task Force (2014). Vitamin, mineral, and multivitamin supplements for the primary prevention of cardiovascular disease and cancer: U.S. Preventive Services Task Force recommendation statement. Annals of Internal Medicine, 160(8), 558–564. doi: 10.7326/M14-0198. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/24566474
- NIH Office of Dietary Supplements (2020). Vitamin A. Retrieved from https://ods.od.nih.gov/factsheets/VitaminA-HealthProfessional/
- Riahi, R. R., Bush, A. E., & Cohen, P. R. (2016). Topical Retinoids: Therapeutic Mechanisms in the Treatment of Photodamaged Skin. American Journal of Clinical Dermatology, 17(3), 265–276. doi: 10.1007/s40257-016-0185-5. Retrieved from https://pubmed.ncbi.nlm.nih.gov/26969582/
- The ATBC Cancer Prevention Study Group. (1994). The alpha-tocopherol, beta-carotene lung cancer prevention study: design, methods, participant characteristics, and compliance. Annals of Epidemiology, 4(1), 1–10. doi: 10.1016/1047-2797(94)90036-1. Retrieved from https://pubmed.ncbi.nlm.nih.gov/8205268/
Dr. Steve Silvestro is a board-certified pediatrician and Manager, Medical Content & Education at Ro.