How Much is Too Much?
Excess Vitamins and Minerals in Food Can Harm Kids’ Health
June 19, 2014
How Much is Too Much? : Executive Summary
Getting sufficient amounts of key nutrients is important for a healthy diet, but many Americans don’t realize that consuming excessive amounts of some nutrients can be harmful. Food producers often fortify foods with large amounts of vitamins and minerals to make their products appear more nutritious so they will sell better. Because the Food and Drug Administration’s current dietary Daily Values for most vitamins and minerals were set in 1968 and are woefully outdated, some products may contain fortified nutrients in amounts much greater than the levels deemed safe by the Institute of Medicine, a branch of the National Academy of Sciences.
EWG’s review of fortified foods currently on the market found that young children are at risk of consuming too much of three nutrients – vitamin A, zinc and niacin. Fortified breakfast cereals are the number one source of excessive intake because all three nutrients are added to fortified foods in amounts calculated for adults, not children. The FDA’s current Daily Values for these three nutrients are actually higher than the “Tolerable Upper Intake Level” calculated by the Institute of Medicine for children 8 and younger. Pregnant women and older adults may also be at risk of consuming too much vitamin A from other fortified foods, such as snack bars.
Nutrient content claims are used as marketing tools. High fortification levels in a product can induce consumers to buy certain foods because they seem “healthier” even though they might not be, as the Institute of Medicine has pointed out in multiple reports (IOM 1990; IOM 2010).
Vitamin A, zinc, and niacin are all necessary for health, but too high doses can cause toxic symptoms. Routinely ingesting too much vitamin A from foods such as liver or supplements can over time lead to liver damage, skeletal abnormalities, peeling skin, brittle nails and hair loss. These effects can be short-term or long lasting. In older adults, high vitamin A intake has been linked to hip fractures. Taking too much vitamin A during pregnancy can result in developmental abnormalities in the fetus. High zinc intakes can impair copper absorption and negatively affect red and white blood cells and immune function. Niacin is less toxic than vitamin A and zinc, but consuming too much can cause short-term symptoms such as rash, nausea and vomiting.
Although many Americans do not eat enough vitamin-rich vegetables, fruits and other fresh products and consequently get too little of some vitamins and minerals, ingesting excessive amounts is also unhealthy. Data from the National Health and Nutrition Examination Survey (NHANES) show that with the exception of vitamins D and E and calcium, dietary deficiencies of vitamins and minerals are rare among children 8 and younger in the United States (Berner 2014). For young children, the problem is the opposite – the risk of too much intake of some nutrients from fortified foods and supplements (Bailey 2012a; Butte 2010).
One recent study by a joint research team of the National Institutes of Health and California Polytechnic State University found that children younger than 8 are at risk of consuming vitamin A, zinc and niacin at levels above the Institute of Medicine’s Tolerable Upper Intake Level. The study found that from food alone, including naturally occurring and fortified sources, 45 percent of 2-to-8-year-old children consume too much zinc, 13 percent get too much vitamin A and 8 percent consume too much niacin (Berner 2014). Similar results have been published by the FDA itself (FDA 2014a) and by a research group at the University of Toronto (Sacco 2013). In contrast, eating fresh foods that naturally contain vitamins and minerals has significant health benefits and, with very few exceptions, has not been linked to excessive vitamin and mineral intake.
It is difficult or impossible to link these nutrient overexposures to specific cases of harm to children’s health, but multiple studies point out that cumulative exposures from fortified food and supplements could put children at risk for potential adverse effects (IOM 2003; IOM 2005). Multiple expert reviews conducted in the United States and in Europe have highlighted the health risks of high vitamin and mineral fortification of foods (BfR 2005; BfR 2006; EFSA 2006; IOM 2001; UK EVM 2003).
EWG analyzed the data on Nutrition Facts labels for breakfast cereals and snack bars, two food categories that are frequently fortified and heavily marketed for children. EWG’s analysis was based on data gathered by FoodEssentials, a company that compiles information on foods sold in American supermarkets. EWG reviewed 1,556 breakfast cereals and 1,025 snack bars, identifying 114 cereals fortified with 30 percent or more of the adult Daily Value for vitamin A, zinc and/or niacin and 27 snack bars fortified with 50 percent or more of the adult Daily Value for at least one of these nutrients.
A number of factors make children’s excessive intake of vitamin A, zinc and niacin a health concern:
• These micronutrients are present naturally in food and are also added to many foods children and toddlers eat, including milk, meat, enriched bread and snacks.
• Many cereals and snack bars are fortified at levels that the FDA considers high, exceeding the amounts children need and in some cases exceeding the safe upper limits for young children in a single serving.
• Intentional or accidental fortification “overages” by manufacturers can make actual exposures greater than the amounts indicated on the nutrition label.
• Many children eat more than a single serving at a sitting because the serving sizes listed on many packaged foods do not reflect the larger amounts people actually eat.
• A third of all children, and as many as 45 percent of the younger age groups, take dietary supplements (Bailey 2013).
Excessive exposure to fortified nutrients is the result of unscrupulous marketing, flawed nutrition labeling and outdated fortification policy. The current nutrition labeling system puts children’s health at risk and is in dire need of reform. The FDA’s recently proposed reforms (FDA 2014b; FDA 2014c) are a step in the right direction, but they remain insufficient to protect children’s health from over-consumption of fortified micronutrients.
To address these problems, the FDA must set percent Daily Value levels that reflect current science; require nutrition labels on products marketed for children to display percent Daily Values specific to each age group, such as 1-to-3-year-olds and 4-to-8-year-olds; and update the serving sizes cited on Nutrition Facts labels to accurately reflect the larger amounts that Americans actually eat. The FDA should also modernize its 1980 guidelines on voluntary food supplementation, particularly for products that children eight years old and younger may eat. Food fortification policy must be based on specific risk assessments for each nutrient and for specific population groups.
EWG recommends that parents give their children products with no more than 20-to-25 percent of the adult Daily Value for vitamin A, zinc and niacin and monitor their children’s intake of these and other foods so kids do not get too much of these nutrients. Because too much vitamin A can cause birth defects, EWG also recommends that pregnant women watch their intake of products fortified with vitamin A, especially if they are taking a vitamin pill. Older adults should also carefully monitor vitamin A in their diets and supplements in order to avoid the risks of osteoporosis and hip fractures associated with high vitamin A intake.
Finally, it is critical that the FDA take seriously the question of how food manufacturers may misuse food fortification guidelines and nutrient content claims to sell more products, particularly those of little nutritional value.