© 2019 Gwen Dewar, Ph.D., all rights reserved
Vitamin A supplements are helpful for children who have a vitamin A deficiency. But most healthy, well-nourished kids don’t need supplements. And some kids may be getting too much vitamin A — consuming excessive levels of preformed vitamin A in liver, dairy products, fish oil, multivitamins, and certain vitamin-fortified foods.
What is vitamin A?
The term “vitamin A” refers to a group of organic compounds that include
- preformed vitamin A (compounds like retinol, retinal, retinoic acids, and retinyl palmitate, which are derived from animal products, and easily used by the human body); and
- provitamin carotenoids (plant-based pigments that our cells can convert into provitamin A).
Perhaps the best-known provitamin carotenoid is beta carotene, which give carrots, sweet potatoes, apricots, and other fruits and vegetables their bright orange color.
Why do we need vitamin A?
Small amounts of A are essential for good health.
- During gestation, babies need vitamin A for the normal development of their organs.
- Vitamin A is required for gene transcription, and for the proper functioning of the immune system.
- Vitamin A is crucial for the development of the eye, and for everyday visual function, including the ability to see under dim lighting conditions.
- Vitamin A deficiency may worsen symptoms of autism for children with autism-spectrum disorders (Guo et al 2018).
Worldwide, children with clinical deficiencies of vitamin A are more likely to suffer from a variety of infectious diseases, and are at risk for visual problems, including blindness.
Vitamin A deficiencies are relatively rare in wealthy countries like the United States. But in developing countries, vitamin A deficiency is common, and a major cause of both blindness and child mortality (World Health Organization 2009; Bendich and Langseth 1989).
What are good sources of vitamin A?
There are two main dietary sources — animal and plant.
The most concentrated sources of preformed vitamin A come from animal livers, but, as I note below, liver may actually be too rich in vitamin A. People should consume it in small amounts.
Other, more moderate animal sources of preformed vitamin A include oily fish, like salmon, and dairy products made from milk fat, like butter and ghee.
Plant sources of vitamin A include the beta carotene vegetables mentioned above — carrots, pumpkin, sweet potatoes, apricots, mangoes, papaya, and cantaloupe. Beta carotene is also found in dark, green, leafy vegetables, like spinach and kale.
What about vitamin A supplements?
Commercially-prepared vitamin A supplements usually consist of retinyl palmitate — preformed vitamin A. Some supplements contain beta carotene.
And some foods are artifically fortified with preformed vitamin A. These may include milk products, cooking oils, and cereals.
Can too much vitamin A hurt you?
We need a certain amount of vitamin A, and consuming plant-based carotenoids is generally safe. Because of the way the body processes carotenoids, you can’t really overdose of vitamin A by eating fruits and vegetables.
But too much of the animal form of vitamin A — preformed vitamin A — can cause health problems.
When consumed in excess, preformed vitamin A can cause weakness, headaches, nausea, dry skin, and other symptoms. Over time, a chronic excess of preformed vitamin A can cause joint pain and the decalcification of bone — leading to osteoporosis (Rutkowski and Grzegorczyk 2012).
So vitamin A supplementation — prescribed by a doctor — can be a helpful therapy if you suffer from a vitamin A deficiency. But if aren’t deficient, supplements can be problematic, because it’s relatively easy for an otherwise healthy, well-nourished person to take in too much preformed vitamin A.
For example, in the United States, a random, national sample of more than 3,000 children found that 97% of toddlers taking multivitamins were getting excessive amounts of vitamin A — amounts above the “Tolerable Upper Intake Level.” Even among toddlers who didn’t take supplements, 15% were getting too much vitamin A (Briefel et al 2006).
But what, exactly, do we mean by “too much” vitamin A?
Recommended vitamin A intake
Consider the recommended daily allowances for vitamin A promoted by the U.S. National Institutes of Health. These reflect how much vitamin A a child should get, on average, each day.
I list them here in RAE (“retinol activity equivalents”), which measured in micrograms (μg) per day. I also provide the equivalent in “international units” (IU), which are found on some food and vitamin labels.
Recommended daily allowances per day by age
1-3 years — 300 RAE µg/day (1000 IU)
4-8 years — 400 RAE µg/day (1330 IU)
9-13 years — 600 RAE µg/day (2000 IU)
Now consider the “Tolerable Upper Intake Level” (UL)—the amount of preformed vitamin A that kids shouldn’t exceed:
Recommended maximum intake per day by age
1-3 years — 600 RAE µg/day (2000 IU)
4-8 years — 900 RAE µg/day (3000 IU)
9-13 years — 1700 RAE µg/day (5660 IU)
Again, note that this second chart lists the maximum recommended daily intake of preformed vitamin A. It doesn’t address carotenoids.
If your kids are satisfying their vitamin A requirements by consuming carotenoids, you don’t need to worry about limiting their intake.
But if your child is consuming the animal form of vitamin A — from animal products, supplements, and fortified foods, you need to be careful.
How sources of preformed vitamin A can add up
According to the U.S. National Institutes of Health, 3 ounces of beef liver contains 6,582 RAE µg of preformed vitamin A — more than twice the maximum recommended daily intake for children under the age of 8.
Clearly, young children should eat liver very sparingly, if at all. But even if you avoid liver, there are other sources of preformed vitamin A, and they can add up.
For example, take a look at these dairy products:
- Ice cream, French vanilla. One cup has 278 RAE µg (83 IU).
- Milk, 2% fat, fortified with A. One cup (237 mL) has 139 RAE µg (464 IU).
- Butter. One tablespoon (15 mL) has over 95 RAE µg (317 IU).
- Cheddar cheese. One ounce (28g) has about 84 RAE µg (281 IU).
- A boiled egg has approximately 78 RAE µg (260 IU).
- Whole milk yogurt. Eight ounces (227 g) has 67 RAE µg (225 IU).
- Cottage cheese, 2% fat. One cup (237 mL) has 50 RAE µg (167 IU).
And the amount of preformed vitamin A in oily fish:
- Pickled Herring. Three ounces has 219 RAE µg (731 IU)
- Mackerel. Three ounces has about 65 RAE µg (214)
- Salmon, sockeye. Three ounces has 59 RAE µg (176 IU)
Next, consider how much preformed vitamin A has been added to certain processed foods, like breakfast cereal and frozen waffles. According to the National Institutes of Health, a cup of fortified cereal might contain as much as 130-150 RAE µg of preformed vitamin A.
And read the label on your multivitamins and dietary supplements. Here in the United States, I have found a number of children’s multivitamins that contain retinyl palmitate, a type of preformed vitamin A. Their labels typically advise parents to give their children doses of up to 630 RAE µg (2100 IU) per day.
So it’s easy to see how a child could get too much preformed vitamin A by consuming a combination of animal products, vitamin-fortified processed foods, and multivitamins.
A young child who eats just a few of the food items on these lists — a cup of milk, a cup of fortified cereal, an ounce of cheese, and a bit of butter — will have already taken in approximately 400 RAE µg of preformed vitamin A. Add a multivitamin, and that child will be exceeding the Tolerable Upper Intake Level.
How much does this matter? Should I worry if my child has been getting too much preformed vitamin A?
In the study of American toddlers, the vast majority of kids taking vitamin supplements were getting too much vitamin A. But that doesn’t mean they were suffering adverse effects.
When health agencies set a tolerable upper intake level, they include a safety margin. Typically, the value is set at 2.5-fold lower than the daily intake associated with documented health problems.
It’s also not clear how often multivitamin supplements and fortified foods actually deliver what they claim.
For instance, sunlight reduces the potency of retinol, and many children’s vitamins are sold in trasparent plastic bottles. How potent are kids’ vitamins, really? I haven’t found any answers to that question. Perhaps researchers will address this point in the future.
What’s more certain, however, is that many children — healthy, well-nourished children — are taking in more preformed vitamin A than they need. It’s wasteful at best.
If a child is consuming lots preformed vitamin A, it may contribute to long-term health problems.
As noted above, chronic over-consumption of preformed vitamin A can cause symptoms of illness, and bone loss.
Vitamin A overdose during can also cause birth defects, which is why prenatal vitamin supplements are supposed to contain beta carotene–NOT preformed vitamin A.
And children’s multivitamins are often packaged as sweets or gummy candies, which can entice kids to consume too much. It’s important to keep vitamins stored in child-proof bottles, and talk to your doctor if you suspect your child has gotten into them.
In short, there’s no reason to panic. But it’s wise to be aware of the sources of preformed vitamin A in your child’s diet, read labels, and chose vitamin supplements carefully.
Unless a child is vitamin A deficient, he probably doesn’t need to consume any preformed vitamin A supplements at all. In fact, a well-nourished kid can satisfy her vitamin A requirements by eating fruits and vegetables high in carotenoids. A half cup of raw carrots contains more than 450 RAE µ of vitamin A.
More information
The numbers cited in this article — about the vitamin A content in foods — come from the US government sources. You can read more in this fact sheet by the National Institutes of Health. It includes a list of foods rich in beta carotene. In addition, you can look up nutritional information about specific foods in the USDA Nutrient Database.
And to see other Parenting Science articles about nutrition, see this index.
References: Vitamin A supplements
Bendich A and Langseth L. 1989. Safety of vitamin A. Am J Clin Nutr. 49(2):358-71.
Briefel R, Hanson C, Fox MK, Novak T, and Ziegler P. 2006. Feeding Infants and Toddlers Study: do vitamin and mineral supplements contribute to nutrient adequacy or excess among US infants and toddlers? J Am Diet Assoc. 106(1 Suppl 1):S52-65.
Guo M, Zhu J, Yang T, Lai X, Liu X, Liu J, Chen J, Li T. 2018. Vitamin A improves the symptoms of autism spectrum disorders and decreases 5-hydroxytryptamine (5-HT): A pilot study. Brain Res Bull. 137:35-40.
Institute of Medicine (US) Panel on Micronutrients. 2001. Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc. Washington (DC): National Academies Press (US); 2001.
National Institutes of Health Office of Dietary Supplements. Vitamin A: Fact sheet for professionals. Accessed 5/3/2019 at https://ods.od.nih.gov/factsheets/vitamina-healthprofessional/.
Rutkowski M and Grzegorczyk K. 2012. Adverse effects of antioxidative vitamins. Int J Occup Med Environ Health. 25(2):105-21.
World Health Organization. 2009. Global prevalence of vitamin A deficiency in populations at risk 1995-2005: WHO global database on vitamin A deficiency. Geneva: World Health Organization.
Content last modified 5/2019
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