Vitamin A (as retinyl palmitate)

What is vitamin A?

Vitamin A is a fat-soluble vitamin that the body uses to build the light-sensitive pigments in the retina, to keep the surface of the eye moist and healthy, and to support skin, mucous membranes, immunity and normal growth. It comes in two main forms. Preformed vitamin A (retinol and its esters, such as retinyl palmitate) is found in liver, fish oils, dairy foods, eggs and fortified foods. Provitamin A carotenoids, mainly beta-carotene, come from orange and dark green plant foods and are converted to vitamin A as the body needs it. Supplements may contain either form.

What the research says

The link between vitamin A and vision is well established. MedlinePlus explains that retinol helps produce the pigments in the retina and that vitamin A promotes good eyesight, especially in low light. A lack of vitamin A can cause reversible night blindness and, if severe, permanent damage to the cornea called xerophthalmia. Worldwide, vitamin A deficiency is a major cause of preventable blindness in children, but MedlinePlus notes that deficiency is very rare in the United States.

For people who already get enough, there is no good evidence that extra vitamin A sharpens vision or protects against age-related eye disease. The original AREDS formula used beta-carotene, not retinol, and AREDS2 later replaced beta-carotene with lutein and zeaxanthin because beta-carotene was linked to more lung cancers in current and former smokers. MedlinePlus also notes that beta-carotene supplements may raise cancer risk in smokers and asbestos-exposed workers.

Safety matters more with preformed vitamin A than with many nutrients because the body stores it. MedlinePlus warns that too much can build up and cause serious problems, that large doses in pregnancy can cause birth defects, and that chronic toxicity can occur in adults who regularly take very high amounts. Symptoms of excess can include headaches, nausea, dizziness, liver damage and bone problems.

How it’s used in supplements

Vitamin A appears in most multivitamins and in many eye, skin and immune formulas. Labels list it in micrograms of retinol activity equivalents (mcg RAE) and often state the form. A dose around the Daily Value of 900 mcg is a typical amount and is well below toxic ranges for healthy adults, but it adds to vitamin A from food, fortified products and other supplements. If you already take a multivitamin, check the total. Pregnant women and people with liver disease should not take extra preformed vitamin A without medical advice, and people who smoke should avoid high-dose beta-carotene supplements.