When parents consider their child’s nutrition they usually don’t think about the problem of getting too many nutrients, especially vitamins. Most parents worry about the opposite problem, presented in our last post: nutrients children may be missing.
But with a food supply dramatically different than it was just 30 years ago, and the popularity of vitamin supplements, kids can most definitely get certain nutrients in higher-than-expected levels. And more is not always better.
In our second post in our Kids’ Nutrition Series, we’re talking about some ways your child could be getting too much of nutrients essential for health — and what you can do about it.
But first, a brief history of why this is a concern in the first place.
Nutrients already added to food
In the 1900s the process of adding vitamins back to refined flour became popular because of the development of pellagra (niacin deficiency) and beriberi (thiamin deficiency). An international effort for enrichment was initiated in the 1940s during World War II that included flour and bread products (niacin, thiamin, riboflavin and iron).
Enriched means that the nutrients added are replacing what is lost during processing and fortification is when nutrients are added to foods that didn’t have them in the first place.
In the 1980s and 90s evidence began to mount regarding folic acid’s role in helping prevent neural tube defects in babies, such as spina bifida. While it was a long road to get there, in 1996 the FDA published its final rule adding folic acid to the list of nutrients listed above.
In more recent years fortification of food products has exploded. While the FDA tried to tighten regulations around food fortification, they were not successful and instead settled for a “policy statement” aimed to help manufacturers follow sensible practices.
What does this all mean?
While enriched foods (plus folic acid) have benefited the public with classic nutrient deficiencies practically eradicated and neural tube defects on the decline, the benefits of the new wave of fortified foods and dietary supplements are not so clear.
Many products are now fortified — cereals, energy bars, breakfast bars, waffles, yogurts and beverages — and about half the population is taking multivitamins. The result? It’s not that hard for people to get more than we know is good for them. And here are the concerns:
According to the Feeding Infants and Toddlers Study (FITS), 6% of toddlers and 30% of preschoolers exceeded the Tolerable Upper Intake Levels (ULs) set by the Institute of Medicine for folic acid. And data from the National Health and Examination Survey (1988-2004), show the highest levels of serum folate were found in children between 4-11 and the elderly.
The main concern with excess folic acid has always been that high folate levels can mask the signs of vitamin B12 deficiency. But now preliminary research (not proven folks, just some red flags being raised) is showing a potential relationship between high folate levels, from fortified foods and supplements, and risk of certain cancers, heart disease and cognitive decline in the elderly.
When people refer to folic acid, they are talking about the synthetic form of folate in fortified foods and supplements. Folate is found naturally in foods like greens, orange juice and peas. What’s interesting is the synthetic form, folic acid, is more highly absorbable than the natural form.
Gerard E. Mullin, MD, from Johns Hopkins University School of Medicine sums it up nicely in his recent article in Nutrition in Clinical Practice:
“The data at times are conflicting and even show duality — some folate is good but perhaps too much is harmful. Overall the evidence supports the notion that a well-rounded intake of folate from fruits and vegetables appears safe, but overconsumption of folic acid from supplements and fortification of bread and cereal products may have a ricochet effect.”
Folic acid excesses are more likely in younger children where the ULs are much lower. For example, you have a three-year-old girl who eats plenty of grains that are fortified with folic acid. She also has fortified cereal in the morning (200mcg per serving for 50% DV) a cereal bar for a snack (100mcg) and her mom gives her a multivitamin at night because she doesn’t eat many fruits and veggies. She easily exceeded the upper limit for her age (300mcg).
The tolerable upper limits of folic acid for 1-3 year olds is 300mcg, 4-8 (400mcg), 9-13 (600mcg) and 14-18 (800mcg). Remember the Daily Values (DV) are based on adults needs. The DV for folic acid is 400mcg.
According to the FITS study, 31% of toddlers and 59% of preschoolers exceeded the ULs for preformed vitamin A.
“In our study of children 8-11 years old in Hawaii, we found that very few children exceeded the ULs,” says Suzanne Murphy, PhD., RD., researcher at the University of Hawai‘i Cancer Center. “And when they did, vitamin A was the nutrient most likely to be too high.”
Murphy goes onto explain that the ULs for children are set at a conservative level, and apply to usual, long-term intake: “Intakes that are consistently above the UL (for months or years) are more a cause for concern. High intakes of retinol (the form of vitamin A that’s found in most supplements and fortified foods), for example, can result in many toxic effects including skeletal abnormalities, bone tenderness and pain, hair loss, fever, headache, and weight loss, ” she adds.
Preformed vitamin A (retinol) comes from animals and other sources including liver, whole milk, and fortified food products and supplements. Provitamin Ais found in colorful fruits and vegetables (e.g, beta carotene in carrots) that can be made into retinol in the body and is also in some supplements.
Vitamin A, like folic acid, is found in many fortified foods and dietary supplements.
Other excess nutrients — and what parents can do
According to the FITS study 45% of toddlers and 78% of preschoolers exceeded the ULs for sodium. And even though the percent of calories from fat was lower than current recommendations in 47% of preschool children, 76% had more than the recommended amount of saturated fat in their diets. Both of these nutrients are likely due to convenience foods high in sodium, salt, sugar and fat. Zinc intakes, expect for older infants, exceeded the ULs in many cases although toxicity does not appear to be a concern.
While we’ll talk about making the decision to supplement in another post, the point of this article is to help you see all the ways your child gets “extra” nutrition.
“Concerns arise, when children are given adult products, are given more than one dose per day, or when they gain access to what they view as candy,” Murphy says. “Intakes can also be too high if children are already consuming highly fortified foods such as breakfast cereals.”
The bottom line:Some kids who are eating fortified foods and taking supplements simply might be getting too much of nutrients like vitamin A and folic acid. Check all the sources of extra nutrition your child is getting — and you might be surprised what you find.
Butte NF, Fox MK, Briefel RR, Siega-Riz AM, Dwyer JT, Deming DM, Reidy KC. Nutrient intakes of US Infants, toddlers, and preschoolers meet or exceed dietary reference intakes. J Am Diet Assoc. 2010;110:S27-S37.
Mullin GE. Folate: Is too much of a good think harmful? Nutrition in Clin Practice. 2011Feb;26(1):24-27.
Bailey RL, McDowell MA, Dodd KW, Gahche JJ, Dwyer JT, Picciano MF. Total folate and folic acid intakes from foods and dietary supplements of US children aged 1-13 y. Am J Clin Nutr.2010 Aug;92(2):353-8. Epub 2010 Jun 9.
Martin et al., Contribution of dietary supplements to nutrient adequacy among children in Hawaii. J Am Diet Assoc 2008;108:1874-1880