Interest in vitamin A has surged recently, particularly in relation to measles, with Google searches on the topic increasing by more than 5,000% in the past month, New York Post reports.
This spike follows comments from Health and Human Services Secretary Robert F. Kennedy Jr., who highlighted vitamin A as a potential aid against measles, a disease that has seen over 245 reported cases and two deaths in the US this year.
While vitamin A is essential for overall health, experts warn that excessive intake can be harmful. Here’s what the nutrient can—and can’t—do.
Vitamin A is a fat-soluble nutrient that plays a crucial role in vision, immune function, reproductive health, and skin maintenance. It also acts as an antioxidant, helping to protect cells from damage.
Because the body cannot produce vitamin A on its own, it must be obtained through diet. Foods rich in vitamin A include dark leafy greens, carrots, sweet potatoes, cantaloupes, eggs, milk, and liver. In the US, vitamin A deficiency is rare but can occur in individuals with conditions that impair nutrient absorption.
One of vitamin A’s most well-known functions is supporting vision, particularly in low-light conditions. A deficiency can lead to night blindness and increase the risk of vision problems such as cataracts and macular degeneration.
The nutrient also supports the immune system by aiding in the production of white blood cells, which help fight infections. Additionally, vitamin A plays a role in fertility, fetal development, and skin health. Retinoids, a synthetic form of vitamin A, are commonly used in treatments for severe acne and psoriasis, and topical applications may help reduce wrinkles and fine lines.
Some studies suggest that a diet rich in vitamin A may be linked to a lower risk of certain cancers, including breast, colon, and esophageal cancer. However, more research is needed to confirm these findings.
While vitamin A deficiency has been associated with more severe measles infections, experts caution against viewing the nutrient as a standalone treatment or prevention method.
In a 2005 study, children under the age of two who were vitamin A-deficient and diagnosed with measles saw reduced mortality rates after receiving high doses of the nutrient. Based on this, the Centers for Disease Control and Prevention (CDC) recommends vitamin A supplementation under medical supervision for individuals with measles, particularly those with moderate to severe cases.
However, medical professionals emphasize that vitamin A is not a substitute for vaccination.
“Vitamin A cannot replace vaccination,” said Dr. Roy Gulick, chief of infectious disease at NewYork-Presbyterian and Weill Cornell Medicine. “Vitamin A neither treats measles nor prevents measles.”
While vitamin A is essential, too much can lead to serious health issues. Unlike water-soluble vitamins that the body excretes, excess vitamin A is stored in body fat and the liver, which can lead to toxicity over time.
High doses—above 200,000 micrograms in a single intake—can cause nausea, vomiting, dizziness, and blurred vision. Long-term excessive intake (above 3,000 mcg per day) has been linked to bone thinning, liver damage, joint pain, and skin irritation. Pregnant individuals should be particularly cautious, as too much vitamin A can lead to birth defects.
Additionally, vitamin A can interact with medications, reducing their effectiveness. At least 23 drugs are known to be affected by high vitamin A intake, so consulting a doctor before taking supplements is recommended.
For most people, a balanced diet provides sufficient vitamin A, making supplementation unnecessary. However, individuals with certain medical conditions that affect nutrient absorption may benefit from vitamin A supplements under medical supervision.
Ultimately, while vitamin A plays a crucial role in health, relying on it as a primary defense against measles or other serious illnesses is not supported by current medical evidence. Maintaining a well-rounded diet and following recommended vaccination guidelines remain the best approaches to disease prevention.
