The Facts About Perchlorate and Food

Early in 2008, the Food and Drug Administration (FDA) posted new information on its Web site regarding exploratory data on perchlorate and food See FDA's Questions and Answers... based on the results of its latest Total Diet Study ¹.

Placing the new detections in perspective, the agency has stated, "FDA is not recommending any changes to infants' and children's diets and eating habits based on current perchlorate data. FDA continues to recommend a healthy eating plan, consistent with the Dietary Guidelines for Americans, that emphasizes fruits, vegetables, whole grains, and fat-free or low-fat milk and milk products; includes lean meats, poultry, fish, beans, eggs, and nuts; and is low in saturated fats, trans fats, cholesterol, salt (sodium) and added sugars."

Some important considerations regarding this information:

1. The levels of perchlorate in foods are well below the recommended reference dose of 24.5 parts per billion (ppb).

   • Based on the FDA research, the average daily exposure for women of childbearing age is roughly seven times less than the EPA reference dose, and all FDA exposure estimates for all age groups were below the EPA reference dose.

   • FDA's findings appear to corroborate earlier statements presented in a 2004 press release from the American Thyroid Association noting that the weight of scientific evidence indicates it's highly unlikely the levels of perchlorate detected in foods have any measurable health effect. Read more...

   • To put these most recent findings in common sense terms, a person would drown in milk, for example, before perchlorate could pose a health risk. The highest level detected in some samples of milk was 11.3 parts per billion (ppb). According to Dr. Michael Payne, a toxicologist at the University of California at Davis, a person would have to drink an impossible 2'000 eight-ounce glasses of milk a day at least, for weeks or months, before there could be any risk of adverse health effects from perchlorate. Read more about health effects...

2. Levels of perchlorate found in the FDA research have no measurable effect on the body and are indistinguishable from the presence of natural elements in a serving of common vegetables.

   • Milk, lettuce, broccoli and other products have always contained naturally-occurring compounds called nitrates and thiocyanates, which are considered safe at the levels found in the environment. These elements act exactly the same way as perchlorate in the body, and like perchlorate, they have no adverse impact on the body at low levels. At levels found naturally in foods, they can partially block the thyroid gland's ability to absorb iodine, which it uses to make hormones. It is a widely-held scientific view that this in itself is harmless.

   • This iodine blockage is a natural process that happens every day. As a result of a normal and healthy diet, 50 to 70 percent of the average person's iodine is blocked from their thyroid every day. Experts report that people can experience up to 90 percent of this blockage for a long period of time before there is any risk of negative effects.

   • Perchlorate has no measurable effect on the body at levels below 245 ppb. Even at 245 ppb, perchlorate's incremental contribution to blocking iodine would not exceed two-to-three percent. In other words, at the levels found in FDA's research, perchlorate plays an almost insignificant role in blocking iodine compared to the safe and healthy impact of foods in our everyday diet.

3. The recent FDA report also evaluated the iodine content of the US diet and provide additional reassurance that there is little or no likelihood that dietary perchlorate intake could result in adverse effects.

   • FDA's findings indicate that dietary iodine consistently exceeded current Estimated Average Requirements. This is of particular importance because FDA has also determined that "the impacts of perchlorate exposure will vary depending upon an individual's iodine sufficiency.²" In other words, the impact of perchlorate is reduced in individuals with sufficient iodine intake.

   • The FDA findings emphasize that the US diet is iodine sufficient, which is consistent with recent CDC findings³. The FDA study also found that most perchlorate-containing foods contain relatively higher levels of iodine. Accordingly, it can be expected than anyone eating a perchlorate-rich diet would also ingest higher than usual levels of iodine, thus ensuring both relative and absolute iodine sufficiency.

   • Perchlorate has no measurable effect on the body at levels below 245 ppb. Even at 245 ppb, perchlorate's incremental contribution to blocking iodine would not exceed two-to-three percent. In other words, at the levels found in FDA's research, perchlorate plays an almost insignificant role in blocking iodine compared to the safe and healthy impact of foods in our everyday diet.

4. Detection of perchlorate in more places underscores the need to get the science right when taking regulatory action.

   • New analytical tools have led to the discovery of previously undetectable levels of perchlorate. In some cases, even a source for the presence of the compound is unknown. This discovery - combined with the widely-held scientific view that exposure to the trace amounts now being detected is unlikely to pose a health risk - led the federal government to undertake the deliberative NAS process to obtain the best possible data for setting standards.

   • At the request of the EPA NAS convened a world-class panel of experts to review the best available science on the issue. Fortunately, there are 50 years of research available; dating back to the time perchlorate was used as a medicine in dosages much higher than those being found in the environment. Read More...

   • After nearly two years of reviewing and analyzing the most recent scientific studies, research and data on perchlorate, the NAS issued its report on the health implications of perchlorate in January 2005. The NAS committee concluded that a reference dose of perchlorate at 0.0007 milligrams per kilogram per day is appropriate and protective for all populations, including the most sensitive population - the fetuses of pregnant women who might have hypothyroidism or iodide deficiency.

   • In February 2005, the EPA established its official reference dose of perchlorate at 0.0007 milligrams per kilogram per day, and translated that number to a Drinking Water Equivalent Level of 24.5 ppb.

1.) Murray, et. al, (2008) US Food and Drug Administration's Total Diet Study: Dietary intake of perchlorate and iodine, Journal of Exposure Science and Environmental Epidemiology
2.) US FDA: 2004-2005 Exploratory Survey Data on Perchlorate in Food (Update 2007). (http://www.cfsan.fda.gov/~dms/clo4data.html).
3.) National Center for Health Statistics: Iodine Levels, United States, 2000; CDC: 2007. (http://www.cdc.gov/nchs/products/pubs/pubd/hestats/iodine.htm).