Many people would agree that regularly eating fish is a recipe for a good diet. Such a diet has proven health benefits. For example, eating fatty fish like salmon provides omega-3 fatty acids, which is linked to reducing the risk of heart disease, decreasing the likelihood of age-related macular degeneration, preventing Alzheimer’s, and even adding about 2.2 years to our lives. With all of these benefits, who could possibly imagine that the same fish could possibly be linked to very serious health risks?
Unwary diners may be exposed to serious contaminants including mercury, PCBs (polychlorinated byphenyls), organochlorine pesticides, dioxins, and other environmental contaminants. Of particular concern for the savvy diner is fish raised in aquaculture outside the United States. In fact, 91 percent of U.S. seafood is imported, and half of that is from aquaculture. Consumers are left with a few important questions. First, where does the contamination come from? Second, how is the imported seafood regulated? And finally, what can a consumer do to reduce their risk of exposure?
Answering the first question is not simple. Contamination comes from a variety of sources. In the past century, urban communities and industries have mostly been to blame for releasing the aforementioned contaminants into the environment. Agricultural runoff, which likely contains harmful bacteria or nitrates from fertilizer and chemical herbicides or pesticides, also makes its way through a watershed to pollute aquatic ecosystems. Another source of contamination is from foreign aquaculture farms themselves, which may use antibiotics, feed, or other chemicals not permitted in the U.S.
Fish take in the contaminated water through their gills or skin, ingest contaminated sediment particles, and eat contaminated food. This process is known as “bioaccumulation.” Another related concept is “biomagnification,” which is where concentrations of contaminants increase in animals higher on the food chain. Therefore, fish like salmon, tuna, and tilapia, which are higher on the food chain, or bottom-feeder fish, which ingest more sediment, are more likely to contain more contaminants.
The answer to the second question is slightly less complex, but much more startling. In simple terms, the answer is that the U.S. Food and Drug Administration is responsible for inspection of imported seafood, and it doesn’t do all that much. The FDA only inspects about 2.7 percent of imported seafood, which includes testing that relies only on visual inspection to make sure it is not visibly rotting. But chemical contamination is not visible. Of the 2.7 percent of imported seafood that is inspected, much less is actually lab tested for chemical residues and only about 0.1 percent of all imported food is tested for drug residues. The FDA also tries to regulate by inspecting foreign facilities themselves. However, this method has also proven to be unsuccessful as the FDA had only inspected 1.5 percent of foreign processing facilities in the past six years.
The FDA’s lax regulation of imported seafood is particularly troubling when considering that 25 percent of all food-borne illness outbreaks came from imported seafood. Additionally, the standards in foreign aquaculture farms can be exceedingly low and still be approved for U.S. consumption. For example, a tilapia farm in China feeds fish with pig feces, which can easily result in salmonella contamination or cause disease in the fish. Another example is in Vietnam where shrimp are packed in ice made of tap water that is unsafe for drinking because of bacteria. Clearly, the FDA should be doing more to ensure the safety of U.S. consumers.
Since instituting change in the FDA’s inspection policies will likely take years, what can consumers do to protect themselves in the meantime but still get their omega-3 fatty acids? First, consumers should know where there fish comes from. If it is wild-caught, it is less likely to be contaminated. If it is raised in the U.S., the aquaculture standards are higher and is likely safer. Even if it is wild-caught or raised in the U.S., it is still important to know which watershed it came from to make sure it is not from a contaminated watershed. Second, it is important for consumers to know what kind of fish they are eating. Fish higher on the food chain or higher in fat are more likely to have higher concentrations of contaminants, so consumers should eat a variety of fish. Bottom-feeding fish should be avoided since they likely have higher concentrations of contaminants since they ingest more contaminated sediment. Last, consumers should be aware that certain cooking methods reduce their risk of exposure. Consumers should remove skin and surface fat before cooking the fish. Additionally, cooking methods that allow the fat to drip off the fish, such as grilling, are preferable to methods that do not, such as breading and frying.