By Dr. Mercola
For the past several years, I’ve increasingly recommended avoiding most seafood due to widespread contamination, primarily by mercury, PCBs and other environmental pollutants.
Shrimp, however, due to their small size, have generally been considered to be one of the safer kinds of seafood. But a recent article1 may make you think twice about eating shrimp, unless you know it’s wild-caught from a clean source.
A major part of the problem is farmed shrimp which, like farmed fish, tends to be far more contaminated than its wild-caught counterparts. Aquatic farms of all kinds also pose grave dangers to ecological systems. Another problem is lack of inspection and oversight of imported seafood.
According to the featured article:
“90 percent of the shrimp we eat has been imported, but less than two percent of that gets inspected by US regulatory agencies. What's the big deal?
Imported shrimp, more than any other seafood, has been found to be contaminated with banned chemicals, pesticides... and it skirts food-safety authorities only to wind up on your plate. The number one reason for all that: the dirty conditions in which farmed shrimp are raised.”
What You Need to Know About Farmed Shrimp
As a result of declining seafood stocks of all types, aquatic farms of various kinds have become big business. Unfortunately, aquatic farming has turned loose all sorts of environmental hazards, all of which ultimately threaten your health.
The featured article highlights several disturbing facts about farmed shrimp:
- Contamination is rampant. Farmed shrimp can contain a wide variety of contaminants, including chemical residues from cleaning agents, pathogens like Salmonella and E.coli, along with other contaminants like mouse and rat hair. According to Food and Water Watch, imported shrimp “accounts for 26 to 35 percent of all shipments of imported seafood that get rejected due to filth.”
Another concern relates to chemicals purposefully used on shrimp. Back in 2009, scientists discovered that 4-hexylresorcinol, a preservative used to prevent discoloration in shrimp and other shellfish, acts as a xenoestrogens and can increase the risk of breast cancer in women and reduce sperm counts in men. Xenoestrogens have been associated to a number of human health effects.
A toxicology study2 by the University of Surrey School of Biological Sciences showed that 260 mg/kg of 4-hexylresorcinol was lethal to all cats used in the study, and they also found it was carcinogenic in both the 13-week and two-year long studies. It also caused a high incidence of nephropathy (an autoimmune disease that affects your kidneys) in mice.
While astaxanthin is one of the most profoundly effective antioxidants, farmed shrimp have very little to no astaxanthin and are given synthetic astaxanthin,3 to provide the right color because astaxanthin-deficiency in shrimp produces specimens that look blue rather than pink.
In fact, so-called “blue shrimp syndrome” was a persistent and alarming problem of earlier shrimp farms. It is important to know that synthetic astaxanthin is made from petrochemicals that are not approved for human consumption.
- Shrimp-packing plants are filthy. As reported by Rodale:
“A report published in the November 2012 issue of Bloomberg magazine4 revealed some truly disgusting facts about the conditions in which shrimp are packaged and shipped.
At one particular facility in Vietnam, the magazine's reporters found processing-plant floors littered with garbage, flies buzzing around, and shrimp that wasn't being stored at proper temperatures.
The shrimp itself was packed in ice made from local tap water, which public health authorities warned should be boiled before using due to microbial contamination, potentially exposing the shrimp (and eaters) to more bacterial contamination.
According to Bloomberg, FDA inspectors have rejected 1,380 loads of seafood from Vietnam since 2007 for filth and salmonella, including 81 from the plant the reporters visited.”
- Imported shrimp may contain hazardous antibiotics. Scientists from Texas Tech University's Institute of Environmental and Human Health recently tested 30 shrimp samples for the presence of three classes of antibiotics. The shrimp were obtained from US grocery stores. Two samples of farm-raised shrimp imported from India and Thailand tested positive for nitrofuranzone.5
This drug can promote overgrowth of fungi, and has been found to cause breast cancer in female rats when given orally in high doses. Disturbingly, the shrimp were found to contain levels 28 and 29 times higher than allowable limits set by the FDA.
The antibiotic chloramphenical was also detected in some shrimp samples. Chloramephenical is banned in food production in the US due to potentially severe side effects, including aplastic anemia and leukemia. Shrimp may also be contaminated with penicillin, which can trigger allergic reactions in susceptible individuals who might never suspect shrimp as a potential source.
- Domestic shrimp may be tainted with oil and/or Corexit. The 2010 BP oil spill temporarily closed down shrimp fishing in the Gulf of Mexico, but the fact that shrimp fishing has resumed does not mean the shrimp are 100 percent safe to eat. The National Oceanic and Atmospheric Administration (NOAA) now oversees the Gulf seafood testing program,6 along with the FDA and Gulf states, to prevent tainted seafood from reaching the marketplace. NOAA and FDA developed a chemical test to detect oil and the oil dispersant Corexit in seafood, and claim that over 99 percent of samples have no detectable residue.
However, as reported by the featured article, scientists from the Natural Resources Defense Council (NRDC) have raised concerns about the residue limits used, warning that they’re not low enough to protect pregnant women and their unborn children.
- Non-native shrimp farms contribute to climate change. How’s that, you might ask? When farmed in non-native waters, shrimp are raised in underwater pens built along the coastlines, where native mangrove forests are frequently sacrificed to make room for them.
Mangroves serve many important functions in the environment, including providing a buffer against hurricanes and flooding, absorbing carbon dioxide (mangroves absorb more carbon dioxide than rainforests), and serve as the native habitat for a variety of fish, including snapper, tilapia, sea bass, oysters and crab. According to the featured article, as much as 80 percent of mangroves in the top five shrimp-farm areas (Thailand, Ecuador, Indonesia, China, Mexico and Vietnam) have been destroyed as a result of non-native shrimp farming.
If from a Clean Source, Shrimp Are an Excellent Food
Barring contamination, shrimp, just like fish, can be an excellent nutritious food. The trick is finding wild shrimp harvested from the cleanest cold-water sources possible. For example, shrimp7 are a good source of:
Tryptophan (an essential amino acid) Vitamin B12 Healthful fats, including omega-3, saturated fat and cholesterol Selenium Protein Astaxanthin
Monterey Bay Aquarium Seafood Watch8 rates various seafood sources based on sustainability and other parameters. While some of their “Best Choice” shrimp9 include farmed shrimp, which I cannot in good conscience recommend, some of the wild-caught shrimp on their good-to-best list include:10
- Northern shrimp, caught in US/Canadian Atlantic
- Pink shrimp from Oregon
- Wild-caught rock shrimp from the US
- Spot prawns from British Columbia (Canadian Pacific)
- California coonstripe shrimp (caught using submerged pots. To determine this, talk to your fishmonger or the fishery in question)
Buying Local Increases Food Safety and Food Security
Ideally, you’ll want to buy wild-caught seafood. However, with environmental tragedies like the BP oil spill in the Gulf, and the still-leaking nuclear plant in Fukushima, Japan,11 not to mention the general pollution in waterways across the globe, merely being “wild-caught” is certainly not a guarantee of safety. If you want to eat seafood, I strongly suggest taking the extra step or two to determine how, and from where it was procured. If at all possible, get your seafood from a source that can guarantee its purity through independent lab testing.
I believe that if you choose wisely, the health benefits of fish and other seafood can still outweigh the potential risks from contamination.
Disease in farm animals is one of the biggest sources of epidemics in humans, and fish farms are the aquatic version of a confined animal feeding operation (CAFO), which is why I simply cannot recommend farmed seafood of any kind. Just like their land-based cattle and chicken farms, aquatic CAFOs are a breeding ground for disease and toxic waste, and produce food animals of inferior quality. Due to the dramatically increased disease risk—a natural side effect of crowding—these animals are further contaminated with drugs.
Remember that farmed shrimp are also given synthetic astaxanthin12 made from petrochemicals. When you eat wild shrimp, you get the benefit of natural astaxanthin, but not so with farmed shrimp... In the latter case, you end up eating a chemical that is not even approved for human consumption!
In all, the ramifications of our large-scale, mass-producing, chemical-dependent food system are incredibly vast, which is why I urge you to become more curious about your food: Where, and how was it raised, grown, or manufactured? These things do matter; for your health, and the health and future of our planet. When it comes to seafood, whether we’re talking about fish or shrimp, there’s no doubt that aquatic farms are responsible for environmental damage of massive proportions while simultaneously producing inferior food animals, which is why, as a general rule, I recommend avoiding them.