Seafood safety: It's the dose that makes the poison
Dr. Gina Solomon says the FDA is not protecting Gulf Coast residents from possible seafood hazards.
Thu, Dec 09, 2010 at 05:44 PM
As Capitol Hill kicks off a series of holiday parties celebrating Gulf seafood, and Louisiana House Rep. Steve Scalise says "I challenge the president to a raw oyster-eating contest," it’s a good time to reflect on the principles of an 16th century scientist who famously stated: “The dose makes the poison.” In the case of seafood contamination, this means the more you eat, the higher your risk.
When the Food and Drug Administration (FDA) calculated safe levels for cancer-causing chemicals from oil (Polycyclic Aromatic Hydrocarbons or PAHs) in Gulf seafood, the agency made some assumptions about how much seafood people eat, and used those assumptions as the foundation for its calculations. For example, the FDA assumed that people eat fish about twice a week, and shrimp only once. A serving of shrimp was assumed to consist of about four jumbo shrimp. I have blogged before about the laughter and disbelief from our Gulf Coast partners when they heard these estimates. “Four shrimp don’t even make a Po’ boy sandwich” hooted one of our Gulf Coast friends.
The FDA pulled its numbers from a national survey, not from a Gulf Coast survey, or from any other survey of frequent seafood consumers. But a safety calculation is only as good as the numbers it’s based on. If the foundation is flawed, the house can crumble.
The FDA complained that there was no survey of seafood consumption rates and quantities in the Gulf Coast region. For that reason, we decided to do our own survey.
The results of our survey confirm what local Gulf Coast residents have been telling us — the FDA’s seafood consumption numbers are way too low. In our survey of nearly 550 Gulf coast residents from Louisiana to Florida, 43 percent responded that they eat fish more frequently than the FDA estimates and 54 percent responded that they eat shrimp more frequently than the FDA estimates. The numbers were striking when it came to shrimp consumption rates, where survey responses were 3.6 to 12.1 times higher than FDA estimates. Some subpopulations, particularly Vietnamese-Americans, reported significantly higher seafood consumption rates than other survey respondents (more than double) for fish, shrimp, oysters and crab. In addition, many of our survey respondents are also more vulnerable to contaminants in seafood than FDA accounted for due to smaller body weight — 60 percent reported that they weigh less than the 176 pounds used in the FDA estimates. When coupled with increased consumption rates, this can result in a significantly increased dose of contaminants. Although our Gulf seafood consumption survey did not represent a random sample, the results are significant in that they clearly show that a significant portion of Gulf Coast residents eat substantially more seafood than reflected in the FDA’s risk assessment.
Based on these findings, we are asking the FDA to expedite a reassessment of the safety levels for Gulf seafood to ensure that local dietary patterns and other vulnerabilities are incorporated, and to assure Gulf Coast residents that their health is protected by decisions about seafood safety.
We don’t know exactly how much of the PAHs are in that Gulf shrimp. The few samples reported by FDA show very low levels, but there are so many gaps and flaws in the sampling that those results may not be reliable. So it’s tough to say how close the shrimp actually are to the levels of concern. What we do know is that the assumptions used in the safety calculations matter. For one of our survey respondents, the safety level based on her body weight and diet would be 8.6 times lower than what FDA is currently allowing, and that doesn’t factor in the increased risk she faces as a pregnant or nursing mother.
Other agencies, like the Environmental Protection Agency (EPA) and the World Health Organization (WHO) have developed guidelines that specify the need to account for local seafood consumption rates and the increased risks to vulnerable populations such as children. The FDA, in contrast, has none and has ignored the guidelines established by other agencies. In fact, the underestimates we found in our survey are a symptom of a larger problem. The FDA has been ignoring scientific findings about hazards of chemicals in foods, conducting inadequate monitoring of contaminant levels, and failing to adequately protect vulnerable populations for everything from the plastic allowed in baby bottles to pesticides on produce and mercury in fish.
So to all those folks on Capitol Hill who are chowing down on Gulf seafood at holiday parties: take a look at your plate and count carefully. The FDA’s protection stops at an average of four jumbo shrimp per week. What is party food for you this season is the foundation of a local diet for Gulf Coast residents. The dose does matter and the people of the Gulf — and anyone who eats seafood — deserve for the FDA to get it right.
The results of the Seafood Survey can be found here.
The letter to FDA, along with a full list of the signatories, can be found here.