Dioxins and PCBs: not worth worrying about

There’s no need to worry about dioxins and dioxin-like substances such as PCBs in our food supply.

“Consumers should eat a balanced diet and follow the Dietary Guidelines for Americans, 2010, and should not avoid any particular foods because of dioxin,says a new publication (Feb. 2012) from the US Food and Drug Administration.

The “Dietary Guidelines” recommend Americans increase their consumption of seafood to at least 8 ounces per week, because the benefits of healthy Omega-3 oils and other nutrients including Vitamin D far outweigh any risks from mercury or other contaminants.

And when it comes to Omega-3 content, Atlantic (farmed), Chinook and Coho salmon are at the top of the list of beneficial seafoods.

The FDA publication is related to new information published last week by the Environmental Protection Agency (EPA) about dioxins. The EPA has assessed a number of studies about dioxins and their risks to animal and human health, in an attempt to more accurately determine risk levels, and is publishing its “Reanalysis” in two volumes. Volume 1, which looks at all health effects except cancer, was published Feb. 17. Volume 2, which looks at cancer, has not yet been published.

Volume 1 of the report suggests that an appropriate reference dose (the largest dose before exposure starts increasing health risks) for dioxins and dioxin-like substances is 7 x 10-10 mg / kg / day.

This is based on one study of men in Italy who had a lower sperm count after being exposed to PCBs as boys.

In terms which are slightly easier to understand, that means the EPA suggests people should consume no more than 0.0000000007 milligrams of dioxins per kilogram of their body weight each day for the rest of their lives if they want to avoid any risk of negative effects to their health.

This is interesting from a science perspective, especially since the hundreds of pages of analysis leading up to this number in the report show there is a wide range of opinion on what constitutes risk, how much is too much and what actually matters.

But to the average person in the grocery store agonizing over what to buy, this is worse than useless — in fact, it may actually discourage people from buying healthy food, if this reference dose is used as a club to bash certain foods.

It’s been done before. Despite studies published in the years before and after showing that the benefits of eating farmed salmon outweigh the risks, the most-referenced and well-known scientific study used to bash farmed salmon as “contaminated” is a 2004 study which used an extremely low reference dose pulled from EPA draft guidelines.

This study, and the months of media controversy which followed, actually caused people to buy less salmon, period. Frozen (i.e. wild) salmon sales dropped as well as fresh.

Because people were scared into thinking they were at risk from dioxins in salmon, they decreased the total amount of seafood in their diet, increasing their other health risks, particularly cardiovascular disease.

Most scientists agree that the benefits of eating oily fish, such as salmon, far outweigh the risks. Oily fish contains Omega-3s, which is proven to reduce heart disease in humans. On the flip side, there is no proof whatsoever that dioxins and PCBs in oily fish actually cause cancer in humans.

So ringing the alarm bells about potential risks, while leaving out a fair analysis of the benefits, is dishonest.

A reference dose is just a number. It does not mean that if you exceed that number you are guaranteed to have health problems and it does not mean that if you are careful to stay below that number you are guaranteed to have no health problems.

It means that science shows that after this number is exceeded, bad stuff might happen.

It’s meaningless to the average person in the grocery store.

When it comes to food, the most important decision people need to make is not whether this particular food will bump up their daily consumption of dioxins over the limit and how they can reduce that number tomorrow.

The most important decision people can make about food is to choose a healthy balance of vegetables, fruits, proteins and grains.

In Canada we all learned about “Eating the food pyramid” and those basic guidelines are present in the 2010 “Dietary guidelines” for Americans.

Eat smaller portions. Snack less. Eat less sugar. Eat less junk food. Eat less processed food. Eat lots of vegetables. Eat seafood at least once per week. Go outside.

Leave it to the EPA and FDA to worry about PCB and dioxin levels, and leave it to them to make sure food suppliers meet those standards.

“The U.S. food supply is among the safest and most nutritious in the world. Although the federal food and environmental agencies are concerned about dioxin, EPA’s final Dioxin Reanalysis, Volume 1 (noncancer) document does not change the government’s view of the overall safety of the food supply in this country,” says the FDA report.

The same goes for Canada.

And if people don’t trust government agencies, they are always free to choose whatever food they think is best.

As for us, we are confident that the FDA’s guidelines and recommendations are grounded in good science.


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