Vitamin A might not be as popular as other letter vitamins, but it’s getting its fair share of attention as of late. For starters, some influencers are touting low vitamin A diets as a means to “improve energy, mental and physical health, and reduce inflammation for longevity,” also citing research noting that high levels of fetal retinoic acid (a metabolite of vitamin A) has the potential to result in neurodevelopmental disorders. One vitamin A “truther” even claimed that spinach and cheese pasta, a favorite dish of late actress Michelle Trachtenberg that offers vitamin A, could have been attributed to her premature death from liver disease. (Yikes.)

On the other side of the spectrum, the Centers for Disease Control (CDC) released a new statement claiming that increasing vitamin A administration may be appropriate in combating the recent measles outbreak—which, as of March 6, has afflicted 222 people across 12 states this calendar year.

In light of these conflicting POVs, it may be confusing thinking about what to do about your vitamin A levels. So, what does vitamin A do in and for the body exactly, and does it actually have the potential to combat diseases like the measles?

What does vitamin A do?

Similar to vitamin C, vitamin A supports immune function and then some. “It helps maintain healthy vision (especially in low light), aids in growth and development, and is crucial for reproductive health,” says Joel “Gator” Warsh, MD, a board-certified pediatrician and author of Between a Shot and a Hard Place: Tackling Vaccine Questions with Balance Data and Clarity. Regular intake ensures the proper functioning of the immune system as well as organs, including the heart, lungs, and kidneys. Moreover, it’s beneficial for the health of your eyes and skin.

Again, retinoic acid is a metabolite of vitamin A, meaning vitamin A converts into retinoic acid in the body. “Retinoic acid plays a vital role in gene expression, helping cells to differentiate and develop properly,” Dr. Warsh explains.

Is vitamin A helpful or harmful?

In short, vitamin A is a critical micronutrient that humans to support a range of vital functions. There’s no merit—let alone any evidence—to the idea that a low vitamin A diet can support health and longevity. “There is a lot of misinformation about vitamin A going around, with people extrapolating the possibility of extremely high amounts of vitamin A in supplement form causing toxicity, to mean that any amount of vitamin A is harmful to us,” says Maddie Pasquariello, MS, RDN, a dietitian based in Brooklyn, New York.

First, some perspective: To reach toxicity levels for vitamin A, Pasquariello says you’d have to consume well beyond (like, at least 100 times the amount of) the recommended dietary allowance (RDA), which is pretty much impossible to do through everyday foods. “You'd have to eat uncommon foods—like liver from a polar bear or seal, or beef liver in such high quantities one human couldn't ever eat in a sitting—to be exposed to possible vitamin A toxicity through food,” she explains. “It's just not possible otherwise.” (I’m guessing I’m not the only one for whom these foods aren’t in regular rotation.) 

In addition, Pasquariello and other dietitians on social media explain that beta-carotene—an antioxidant pigment in foods like carrots and sweet potatoes—is often conflated with vitamin A since it *can* convert to the vitamin in the body. However, it only does so at very low rates, and she deems the chance of getting vitamin A toxicity via plant-based foods as nonexistent. 

Yet, too much vitamin A can be a bad thing via certain routes and for specific populations. Dr. Warsh warns that excessive intake, especially from supplements, has the potential to lead to toxicity known as hypervitaminosis A, which can cause liver damage and other serious health issues.

In addition, he mentions that high doses of synthetic vitamin A—such as isotretinoin for severe acne—have been linked to increased risks of adverse side effects (including but not limited to mood and neurological changes and birth defects), thus requiring close medical supervision. “Still, these situations do not reflect the normal dietary intake of vitamin A,” Dr. Warsh shares. Lastly, he cautions that pregnant women should avoid consuming too much vitamin A, particularly from animal sources, as high levels can harm the developing fetus.

Ok, but can vitamin A prevent or cure measles?

As far as vitamin A interventions are concerned for measles, it’s important to note that vitamin A neither prevents nor cures the disease. Rather, vitamin A supplementation has been shown to reduce the severity and complications of measles as well as significantly reduce fatality rates, namely in children in developing countries and/or who have vitamin A deficiency.

“Generally, children in Western society are not deficient in vitamin A so supplementation is not needed,” says Dr. Warsh. Still, if a child in the U.S. is exposed to measles, a pediatrician may suggest a treatment dose of vitamin A, though continuously high amounts aren’t advised. He also emphasizes that neither dietary nor supplemental vitamin A replace vaccination, which remains the gold standard for measles prevention.

Vitamin A: More or less?

Vitamin A is neither a toxic nutrient to avoid nor a miracle intervention to prevent the measles. Instead, it sits squarely in the middle, which isn’t great as clickbait…but most sound health and dietary advice rarely is. A typical adult needs about 700 to 900 mcg a day, which is about one cup of carrots.

“In summary, vitamin A is a critical nutrient that should be consumed in appropriate amounts, which most individuals can achieve through diet alone,” says Dr. Warsh. As such, regular intake of foods that contain or convert to vitamin A—including orange produce, dark leafy greens, fish, and liver—gets his green light for children and adults alike. Both he and Pasquariello note that supplements and high doses of vitamin A are a different story, so caution and oversight from a doctor or a dietitian are always advised.