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Medical Report Says U.S. Must Reduce Dietary Dioxin Exposure
(Beyond Pesticides, July 8, 2003) A recently released report from a joint panel of the Institute of Medicine (IOM) of the National Academies and the Food and Nutrition Board (FNB) recommends the formation of a federal interagency group to develop and implement a public health strategy to reduce human exposure to dioxin, a cancer-causing chemical.

In "Dioxins and Dioxin-like Compounds in the Food Supply: Strategies to Decrease Exposure," the Committee on the Implications of Dioxin in the Food Supply recommends required testing and the establishment of tolerance levels for Dioxin-Like Compounds (DLCs) in forage, feeds, and feed ingredients of animals because humans are often exposed to dioxin through consumption of food-producing animals. Food is the major route for human exposure to DLCs. In general, higher DLC concentrations occur in foods with higher animal fat contents. DLC-exposure levels in adults are greatest from meat, followed by dairy products, followed by fish. In infants, children, and adolescents, most DLC exposure occurs through high-fat dairy consumption.

The report cites the reduction of DLC exposure in girls and young women before they become pregnant as a high-priority risk management intervention item. DLCs are often transmitted from mother to child through breastfeeding. The report states that "preadolescent and teenage girls and young women were of concern to the committee because they accumulate, over time, body burdens of DLCs that can, when they enter their child-bearing years, become a potential source of exposure for their developing infants in utero and while breastfeeding." Infants exposed to high levels of DLC in utero suffered poor psychomotor skills, altered thyroid hormone levels, and reduced neurological optimality.

As an immediate precaution, the report recommends that young women choose low-fat or skim milk and consume foods low in animal fat. Furthermore, "several studies have shown that trimming prior to or discarding fat after broiling, pan-frying, grilling, roasting, and pressure-cooking meats decreases DLC levels in the foods by 50 percent or more."

The report recommends that the government "work with industry to develop voluntary good agricultural, animal husbandry, manufacturing, and transportation practices to achieve reduction in DLCs" through a four-step process: (a) Monitor building materials and bedding for DLC contamination; (b) Eliminate growing foods and forages in high-exposure areas or do not use first-cut forages from high exposure areas; (c) Increase intensive growing practices for livestock; (d) Reduce or eliminate the use of animal fats and oils, which may be high in DLC, as ingredients in animal feeds.

Required testing for DLC levels in forage, feed, and feed ingredients could be one option used to monitor DLC levels around the country, according to the report. DLCs contaminate animal feed by airborne deposition on forage and plants used to make the feed. Furthermore, several billion pounds of animal fat are used annually as a feed ingredient, recycling DLCs deposited in the fat. This leads to the possibility of increased levels of DLCs in meat and other animal products. The data gathered from such testing would be used to form a nationwide database maintained under the guidance of the Department of Agriculture and industry interests. However, such a monitoring organization is unlikely to produce independent recommendations for further dioxin reduction if it is under the influence of the same people who produce the harmful chemical.

"Because the risks posed by the amount of Dioxins found in foods have yet to be determined, we are recommending simple, prudent steps to further reduce dioxin exposure while data are gathered that will clarify the risks," said committee chair Robert Lawrence of the Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD.

In 2001, EPA's scientific advisory committee finalized a report stating that dioxin causes cancer in laboratory animals and possibly humans.

The full text of the report may be read online for free in a prepublication version, or ordered in hard-copy for $33 on the National Academies Press website.