Market research from the Hartman Group, Bellevue, WA, indicates that 60% of parents surveyed indicated that doctors were the most important sources of information on dietary supplements for their children. Source: The Hartman Group, NPD 2000, Bellevue, WA.

BETHESDA, MD—A mother’s body-mass index may be the single most important predictor of a child’s use of dietary supplements, according to a survey of supplement use by children and teenagers presented at an NIH conference on dietary supplements in children.

According to Leanna Lipps Birch, PhD, of the University of Pennsylvania, mothers of children who take dietary supplements tend to have lower body mass indices (BMI) than mothers of children who don’t. Not surprisingly, she also found that young girls (evaluated at age 5, and again at age 7) who took supplements had lower BMIs than nonusers, as well as a smaller mean BMI increase between ages 5 and 7.

Dr. Birch’s study of familial influences on childhood supplement intake is one of a number of recent surveys attempting to track supplement use in children, and tease out the driving factors. While much work remains to be done, some of the who’s, what’s, and why’s of supplement use by kids are coming to light.

Who

Researchers have split children into two groups: young children, generally under age 12, whose parents give them supplements, and adolescents/teens who decide for themselves what they take. National health surveys indicate that approximately half of all preschoolers take some supplements. The percentage seems to drop off as kids grow up.

According to Johanna Dwyer, DSc, director of the Frances Stern Nutrition Center at the New England Medical Center, data from the 1998 NHLBI-sponsored Child and Adolescent Trial of Cardiovascular Health Tracking (CATCH) study indicate 18–20% of 14-year-olds took some supplement products. This study, not yet published, involved 1,532 eighth graders.

Ronette Briefel, DrPH, of Mathematica Policy Research, Inc., presented data from state and federally-funded studies, including the National Center for Health Statistics’ National Health and Nutrition Examination Survey (NHANES) and the USDA’s Continuing Survey of Food Intakes by Individuals (CFSII). Dr. Briefel said supplement use from 1988–1994, “was highest among non-Hispanic white children, followed by Mexican American children, and then non-Hispanic blacks.”

Since mothers are the ones most likely to determine a child’s dietary intake, researchers have dwelled on which mothers are most likely to give supplements to their children. Dr. Briefel notes preschool children who take supplements are more likely than nonusers to have a mother who has at least a high school education. Dr. Birch did not find any income or education correlates, but this may reflect greater socioeconomic homogeneity in her sample.

Other studies have shown children who take supplements are more likely to have adequate nutrition from diet alone than those who don’t. The NHANES study showed that users also eat more fruits and vegetables. Alanna Moshfegh, PhD, research leader at the Beltsville Human Nutrition Research Center for the USDA, reported that children who use supplements are less likely than nonusers to watch TV or videos regularly. Taken together, these studies suggest children who take supplements come from highly nutrition and health-conscious families.

What

Several studies confirm most children who take supplements are taking multivitamins, with or without additional minerals. Teens are more likely to be taking adult doses, said Dr. Dwyer. Among kids under 12 who use vitamins 43% take a multivitamin, and 38% take products specially-formulated for children, said Laurie Demeritt, president of the Hartman Group, a market research firm.

The CATCH study revealed about 80% of users take only one supplement; and only about 1.5% take three or more, said Dr. Dwyer. However, the most recent NHANES study indicates that among teeneagers who take supplements, 7% of girls and 13% of boys take three or more daily.

Many children are also taking large doses of a single nutrient: the CATCH study found 50% of vitamin users took vitamin C or E, with 53% of boys and 36% of girls taking vitamin C, Dr. Dwyer reported. Ms. Demeritt found that in children under 12, the most popular mineral supplements are calcium and zinc.

Among herbal preparations used by children under 12, echinacea accounts for about 16% of total sales, while the most well-known botanicals—goldenseal, grapeseed extract, St. John’s wort, chamomile, and ginkgo biloba—each account for 2–4% of the children’s herbal market, according to Ms. Demeritt.

Makers of supplements and functional foods have clearly taken aim at kids—and their concerned parents—with products including ginkgo biloba for memory, ginseng for energy, kava kava for anxiety, ephedra for weight loss, and androgens for athletic performance or muscular development, and a whole slew of “alternatives” to ritalin including, pycnogenol, valerian, chamomile, fish oils and zinc.

Why

Clearly, supplement use by children is growing, although even multivitamins are not recommended by the AAP for those who eat an adequate diet. The big question is, why are people taking them?

Ms. Demeritt found among kids under 12, 75% of supplement users take them for “general health and wellness,” while 22% take them specifically as supplementary nutrition; 5% will use them for a cold, and only a small percentage take them for specific conditions or health goals. Her research shows parents give supplements as a preventive measure to avoid the cost of medical care, because giving vitamins seems like “good” parenting, or because they perceive their child is not consistently getting good nutrition.

Parents who use herbal supplements are likely to be taking botanicals themselves, says Ms. Demeritt, often because they have been recommended by a specialist (usually a naturopath). The ease of ingestion and minimal side effects are cited as reasons for using herbals. Supplements are generally viewed as harmless despite the fact that the FDA and many experts on nutraceuticals and botanicals warn that “natural” does not always equal “safe.”

Louis Grivetti, PhD, of the department of nutrition at the University of California–Davis, pointed out that advertising for supplements suggests a lot of research has been done. People think, “not using supplements is more risky than using them.” He believes the general public does not trust scientists or government regulators, especially when conventional medicine offers conflicting recommendations. He views gaps in the efficacy of Western medical approaches for common chronic conditions, and the belief that the U.S. food supply does not contain adequate nutrition as key drivers of supplement use.

It’s estimated that one third to one half of patients do not tell their health care providers they are taking supplements, often because they are afraid the provider will discourage supplement use. Even if doctors make a point of asking patients about their use of supplements, they’re unlikely to get a complete picture.