NUTRIENT LIBRARY

Nutrient Library - Vitamin A

Vitamin A

What does it do?
How much do you need?
What are the best food sources?
What happens if you don’t get enough?
What happens if you get too much?
What are some recipes that are good sources of vitamin A?
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What does it do?

Vitamin A, a fat-soluble vitamin, plays an important role in bone growth, reproduction, immune function, hormone synthesis and regulation, and vision. Your eyes need vitamin A to help them convert light into brain signals that allow you to perceive images. Vitamin A works to protect you against infection by helping create healthy white blood cells and by promoting healthy skin. Vitamin A helps cells divide and develop into specialized cells, like blood cells, lung cells, brain cells and other distinct tissues.

How much do you need?

First, you need to understand that you can get vitamin A from animal or plant sources and that these sources are treated differently by the body. Vitamin A from animal foods, supplements and fortified foods is called “preformed vitamin A,” or retinol. Preformed vitamin A is in a form that is highly available to your body. Vitamin A from plant sources comes in the form of carotenoids, primarily beta carotene. To account for the absorption of different forms of vitamin A, scientists created a unit called retinol activity equivalent (RAE). For example, 12 micrograms (mcg) of beta carotene equals 1 mcg of retinol. To complicate matters, nutrition and supplement labels don’t use RAEs; instead they use International Units (IU). We’ve done the conversions for you in the chart below.

The following table lists the recommended intake for healthy people based on current scientific information and accounts for the fact that sources of vitamin A are absorbed by the body differently.

Life Stage Group	Recommended Dietary Allowance / Adequate Intake (see note below)	Tolerable Upper Intake Level (UL) The UL for vitamin A applies only to preformed vitamin A (found in animal foods, most fortified foods and supplements). It does not include vitamin A derived from carotenoids.
Infants	IU, (micrograms RAE/day)	IU, (micrograms/day)
0-6 mo. 7-12 mo.	1,333, (400) 1,666, (500)	2,000, (600) 2,000, (600)
Children
1-3 yr. 4-8 yr.	1,000, (300) 1,333, (400)	2,000, (600) 3,000, (900)
Males
9-13 yr. 14-18 yr. 19-30 yr. 31-50 yr. 51-70 yr. > 70 yr.	2,000, (600) 3,000, (900) 3,000, (900) 3,000, (900) 3,000, (900) 3,000, (900)	5,667, (1,700) 9,333, (2,800) 10,000, (3,000) 10,000, (3,000) 10,000, (3,000) 10,000, (3,000)
Females
9-13 yr. 14-18 yr. 19-30 yr. 31-50 yr. 51-70 yr. > 70 yr.	2,000, (600) 2,333, (700) 2,333, (700) 2,333, (700) 2,333, (700) 2,333, (700)	5,667, (1,700) 9,333, (2,800) 10,000, (3,000) 10,000, (3,000) 10,000, (3,000) 10,000, (3,000)
Pregnancy
< 18 yr. 19-30 yr. 31-50 yr.	2,500, (750) 2,567, (770) 2,567, (770)	9,333, (2,800) 10,000, (3,000) 10,000, (3,000)
Lactation
< 18 yr. 19-30 yr. 31-50 yr.	4,000, (1,200) 4,333, (1,300) 4,333, (1,300)	9,333, (2,800) 10,000, (3,000) 10,000, (3,000)

NOTE: The table is adapted from the Dietary Reference Intakes reports. Recommended Dietary Allowances (RDAs), when available, are in bold type; Adequate Intakes (AIs) are followed by an asterisk(*). RDAs and AIs may both be used as goals for individual intake. RDAs are set to meet the needs of almost all individuals (97 to 98 percent) in a group. For healthy breastfed infants, the AI is the mean intake. The AI for other life stage and gender groups is believed to cover the needs of all individuals in the group, but lack of data means the percentage of individuals covered by this intake cannot be specified with confidence.
UL = The maximum level of daily nutrient intake that is likely to pose no risk of adverse effects. Unless otherwise specified, the UL represents total intake from food, water and supplements.

What are the best food sources?

Preformed vitamin A (a.k.a. retinol) is found in foods of animal origin, such as liver, eggs, milk fortified with vitamin A, fortified cereals and fish. Green leafy vegetables and orange vegetables and fruits supply vitamin A in the form of carotenoids. To easily meet your recommended intakes, the Dietary Guidelines for Americans suggests 3 cups per week of dark leafy green vegetables and 2 cups per week of orange vegetables. See more food sources and calculate your daily intake.

What happens if you don’t get enough?

One of the first detectable signs of vitamin A deficiency is night blindness or the inability to see in dim light. Common in developing countries but rare in the United States, night blindness is a reversible condition that responds rapidly to treatment. However, if the deficiency becomes more severe, it develops into an irreversible condition termed xerophthalmia, which is a drying of parts of the eye that will eventually result in blindness. Other effects of vitamin A deficiency include decreased immune function; dry, scaly skin; problems with reproduction; and cessation of bone growth.

Since vitamin A is a fat-soluble vitamin, it can be stored in the body. Thus, a healthy adult who stopped eating good food sources of the vitamin might not see deficiency symptoms until these stores were depleted—possibly for several months.

What happens if you get too much?

High intakes of beta carotene from foods have not been shown to be toxic in humans, but may cause an unwanted side effect: yellow (or orange) skin. Fortunately, the beta-carotene tinge is harmless and only temporary. High doses of preformed vitamin A from animal foods or supplements can cause both acute (short-term) or chronic toxicity. Signs of short-term vitamin toxicity include nausea, vomiting, headache, dizziness and blurred vision. Chronic toxicity (due to ingestion of large doses for months or years) is often characterized by dry itchy skin, loss of appetite, headache, birth defects, liver abnormalities, central nervous system disorders, and bone and joint pain. Getting too much preformed vitamin A may also result in reduced bone mineral density, which can lead to osteoporosis.