Vitamin A supplements and your daily multivitamin: Is your kids getting too much A?

© 2010 Gwen Dewar, Ph.D., all rights reserved

Some kids need vitamin A supplements.

But most healthy, well-nourished kids don’t—and many are getting too much preformed vitamin A, or retinol.

Vitamin A, or retinol, is essential for good health. Children with inadequate stores of vitamin A are more likely to suffer from a variety of infectious diseases.

In addition, kids with clinical deficiencies of A may experience decreased growth and damage to the eye. In developing countries, vitamin A deficiency is a major cause of child mortality (Bendich and Langseth 1989).

But vitamin A supplements aren’t necessary for most healthy, well-nourished kids. In fact, unless your child has a vitamin A deficiency, there’s a good chance he’s getting too much vitamin A from his daily multivitamin.

In one American study, a random sample found that 97% of toddlers taking multivitamins were getting excessive amounts of vitamin A in their diets. Even among toddlers who didn’t take supplements, 15% were getting too much vitamin A (Briefel et al 2006).

Why is this happening? It’s not because kids are eating too many vitamin-rich fruits and vegetables, like carrots, sweet potatoes, cantaloupe, and broccoli.

These plant foods contain lots of carotenoids, like beta carotene, which can be converted by the body into vitamin A.

But this conversion depends on your vitamin A status.

If your body already has adequate supplies of retinol, the carotenoids don’t get converted into vitamin A.

Even then, the conversion is rather inefficient. By weight, it takes 12 units of beta-carotene to make 1 unit of retinol.

As a result, you don’t have to worry about your kids eating too many carrots or sweet potatoes—at least not from the standpoint of vitamin A toxicity.

The problem of too much vitamin A arises when kids get too much retinol, or preformed vitamin A, from animal sources (like liver), artificially-fortified foods, and vitamin supplements.

Vitamin A supplements we don’t need: Too much retinol in children’s vitamins and artificially-fortified foods

Liver is naturally high in retinol. According to the USDA, just one ounce (28 grams) of cooked chicken liver contains 3731 international units (IU) of vitamin A. That’s enough retinol to satisfy the daily requirements of three kindergarteners.

So kids should eat liver rather sparingly, if at all.

But it’s relatively easy to avoid feeding your kids liver. More troublesome is the problem of vitamin-fortified foods and multivitamin supplements.

Here in the United States, I’m having a hard time finding vitamins for kids that don’t contain excessive levels of retinol.

To see what I mean, consider the recommended daily allowances for vitamin A promoted by the U.S. Institute of Medicine of the National Academy of Sciences. These reflect how much vitamin A your child should get, on average, each day:

Recommended # international units (IU) per day by age

1-3 years -- 1000 IU

4-8 years -- 1320 IU

9-13 years -- 2000 IU

Now consider the “tolerable upper intake level" (UL)—the amount of retinol that kids shouldn’t exceed:

Recommended maximum intake per day by age

1-3 years -- 2000 IU

4-8 years -- 3000 IU

9-13 years -- 5610 IU

Again, this second chart lists the maximum recommended daily intake of preformed vitamin A, or retinol. 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 takes a multivitamin, check out the label. One popular “gummy" supplement I’ve seen includes the instructions that “parents may give each child up to two" gummies per day. According to the label, that would result in the child’s ingesting 2100 IU of retinol.

How much total retinol might a child on these vitamins consume?

“Hidden" vitamin A supplements in your child’s diet

Let’s assume that he doesn’t eat liver. But perhaps he eats these dairy products:

• Milk, 2% fat, fortified with A. One cup (237 mL) has 464 IU of retinol.

• A chicken’s egg, depending on how you cook it, has between 240 and 335 IU.

• Cottage cheese, 2% fat. One cup (237 mL) has 167 IU.

• Cheddar cheese. One ounce (28g) has 284 IU.

• Whole milk yogurt. Eight ounces (227 g) has 225 IU.

• Butter. One tablespoon (15 mL) has over 317 IU.

And then there are other, vitamin-fortified foods—like breakfast cereal, frozen waffles, malted milk and vitamin water.

According to the label, just one ounce (28 g) of a popular oats-based breakfast cereal -- served with ½ cup of skim milk -- contains 15% of the DV, or Daily Value, for vitamin A. The Daily Value for vitamin A is defined as 5000 IU (the recommended intake for an adult male). So that modest bowl of cereal and milk contains about 750 of retinol.

Does it matter?

It’s easy to see how so many of the toddlers in the American study could have consumed too much retinol. In fact, a young child who takes multivitamins and eats lots of dairy products might easily exceed 4500 IU of retinol per day.

That doesn’t mean these kids 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 to me how much retinol remains in a vitamin supplement that’s been stored in a transparent plastic bottle. Sunlight reduces the potency of retinol. How potent are kids’ vitamins, really? I haven’t found any answers to that question. Perhaps researchers will address this point in the future.

Nonetheless, it seems pretty clear that some kids are getting more retinol than they need. And if caregivers err and give their kids too many vitamins...or too much vitamin water...or add liver to their children’s diet...there is the real possibility of a vitamin A overdose.

And a vitamin A overdose can cause liver abnormalities, reduced bone mineral density, and central nervous system disorders.

Vitamin A overdose can also cause birth defects, which is why prenatal vitamin supplements are supposed to contain beta carotene--NOT preformed vitamin A.

So while most parents don’t need to panic, it seems wise to read labels and choose their vitamin supplements carefully.

Unless your child is known to be vitamin A deficient, she probably doesn’t need to consume any preformed vitamin A supplements at all. It seems likely that most kids can satisfy their vitamin A requirements by eating fruits and vegetables high in carotenoids.

Why don't vitamin manufacturers approach children's vitamins in the same way they treat prenatal vitamins--replacing the retinol with beta carotene?

Why don't they simply reduce the retinol in their supplements?

These are good question, and I don't have the answer.

More information

I got my information about vitamin A supplements in foods from the USDA Nutrient database. For more information about the vitamin A content of foods, check out the USDA Nutrient Database for yourself.



References: Why most kids need to avoid 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.

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