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Lately, food product recalls seem to be on the rise. Most recalls are due to bacterial contamination, but periodically the problem is mistakes in ingredient formulation. Food errors
easy to makeEarlier this month, Metabolife International recalled 1.5 million Metabolife Diet & Energy Bars because they contained excessive levels of vitamin A. The bars had been on the market for four months.
Each food bar contained 32,500 IU (9,750 micrograms) of vitamin A -- more than 10 times the adult Recommended Dietary Allowance and more than three times the adult Tolerable Upper Intake Level.
How dangerous were these overly fortified energy bars? It depends.
Pregnant women and children were at greatest risk. A study of more than 22,000 pregnant women reported that a daily dose of vitamin A greater than 3,000 micrograms per day during the first trimester increased the risk of specific birth defects by almost 500 percent. This bar contained three times the amount in the study.
Because these bars are marketed primarily for weight loss, pregnant women and children were not likely target consumers. Still, excess doses of vitamin A can cause liver damage, among other problems, in healthy adults.
Depending on the dose and frequency of intake, damage may not occur for many months or even years. People with existing liver problems and heavy users of alcohol are much more susceptible. For them, adverse effects could show up in less time.
Fortunately, Metabolife's quality-assurance procedures found the problem. Perhaps they should have caught it before the bars went to the market, but they were checking.
How many companies produce foods fortified with micronutrients? How many check their products? This type of mistake is not hard to make. Micronutrients are added in tiny amounts. The amount of excess vitamin A in one Metabolife bar was less than one-hundredth of a gram -- equivalent to a few grains of salt.
Perhaps it's surprising that this type of mistake isn't more common. But then again, it may be. In reality, food-borne illnesses caused by microorganisms pose a more immediate risk, so most state and federal resources go toward ensuring microbial safety of foods.
Vitamins and minerals are potent substances in the body. Seemingly small errors in the formulation of fortified foods can result in dangerous levels of these micronutrients. This is one of many reasons nutritionists encourage people to get most of their nutrients from foods rather than supplements.
Certainly, there is a place for the rational use of supplements and fortified foods, but nature is much more reliable about putting the right amounts of micronutrients into foods.
It is difficult to say how often fortified foods contain excessive nutrients. Consumer Labs recently reported that one-third of the supplements they tested had significantly more or less of various nutrients than their labels indicated. As always, buyer beware!
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Joannie Dobbs, Ph.D., C.N.S., is a food and nutrition consultant
and owner of Exploring New Concepts, a nutritional consulting firm.
She is also responsible for the nutritional analyses
indicated by an asterisk in this section.Alan Titchenal, Ph.D., C.N.S., is a sports nutritionist in the
Department of Human Nutrition, Food and Animal Science,
University of Hawaii-Manoa.