fishHealth experts of all stripes have been promoting seafood, freshwater fish, and fish oil supplements as a healthier protein source compared to red meat and poultry as well as a clean source of essential fatty acids such as Omega-3, but is it true? Do all fish species confer these health benefits? How do you recognize quality in fish? Is it the same for shellfish? There are some important facts that you should know before deciding whether to add fish to your diet.

In the United States alone, the demand for seafood is enormous. The per capita consumption of seafood is over 50lbs per year, which includes the use of fish in the production of nutritional supplements. This includes all types of seafood including shellfish, crustaceans, and sport fish.

Not all of the fish we eat comes from the ocean, or from lakes and rivers, in fact the last 25 years has seen a real boom in the aquaculture industry or ‘fish farming’. Roughly 50% of the global seafood supply is now produced through commercial agriculture facilities.

Which is better to eat then, from the farm or from the wild?

plasticWild caught fish will only be as healthy as the environment they’re taken from. There is currently a perfect storm of environmental concerns brewing in the Pacific Ocean, the primary fishing region of the world. For the last two decades, perhaps earlier, scientists have been warning of the growing quantity of persistent organic pollutants in the world’s oceans, particularly in the Pacific. The organic pollutants (POPs) come from industrial and consumer waste predominantly in the form of plastics. Bottles, caps, packaging, primarily made from plastic contain a diverse number of toxic chemicals that are not only harmful to the marine life, but to humans as well.

According to Dr. Hideshige Takada, Environmental Organic Geochemist at Tokyo University of Agriculture and Technology, “POPs are hazardous human-made chemicals that are resistant to degradation in the environment.  Polychlorinated biphenyls (PCBs), different sorts of organochlorine pesticides (e.g. DDTs and HCHs) and brominated flame-retardants are all POPs.  Because they are basically lipophilic (i.e. have a high affinity for oils and fats), POPs accumulate in fatty tissues of marine organisms.  They have the potential to cause many adverse effects in wildlife and humans (e.g. cancer, malformation, decrease in the immune response, impaired reproductive ability).”

There are some skeptics who argue that the Pacific Ocean is so enormous and so vast that such pollutants are widely dispersed and diluted and pose little to no consequence on human health. Unfortunately, this opinion does not coincide with reality.

There is an oceanic phenomenon called a gyre, which is a series of currents that travel in a circular path and essentially create a very large, but very slow ‘whirlpool’ in a body of water. The center of this gyre is called the ‘convergence zone’.  The Pacific Ocean has two gyres, one in the eastern portion near Japan and Micronesia, the other is about 2000 miles off the West coast of Mexico. These two regions have become affectionately known as the Great Pacific Garbage Patch. Plastics and other man-made waste have become trapped in these currents and have accumulated together to form massive bundles of debris. No one has been able to accurately measure the extent of the debris. It is conservatively estimated to be twice the size of Texas.

pacific garbage patch

These marine plastics contain additives such as plasticizers, antioxidants, anti-static agents and flame retardants.  Some additives and additive-derived chemicals (e.g., nonylphenol, bisphenol A) cause endocrine disruption--that is they interfere with body processes mediated by hormones.  The potential damage from this can be impaired brain development, disabilities in learning and behavior, malformations of the body and limbs, disruption of normal sexual development (including feminization of males or masculinization of females) and increased incidents of cancer (e.g. breast and prostate cancers).

fukushimaWhile the story of industrial and consumer pollution of the Pacific Ocean has been going on for decades, there is a new crisis brewing. In March, 2011, a 9.0 earthquake struck off the coast of Japan and the resulting tsunami caused major structural damage to the Fukushima Daiichi Nuclear Power Plant. Several of the reactors were damaged and one of them was so badly hit the roof caved in. As part of an emergency measure to prevent a full scale meltdown of the reactors, cold seawater was pumped inside in order to cool the radioactive fuel rods. The water, which now contains radioactive particles, is transferred into storage tanks. Several of these storage tanks are leaking and according to TEPCO, the Japanese organization that has been handling the repair and containment of the radioactive waste, an organization that has already admitted to falsifying security documents, claims that so far 400 tons of radioactive water has leaked into the ocean.

The Japanese government has already implemented radiation testing of seafood and other foods grown with nearby groundwater to protect Japanese citizens from consuming radioactive compounds, but the problem has become much larger than this. Research conducted by scientists at the Helmholtz Centre for Ocean Research in Germany, particularly the study by Erik Behrens et al, shows that the radiation leaked into the ocean from this disaster will eventually saturate the entire northern Pacific Ocean with radioactive Cesium-137.

Between the plastic and chemical contamination and the radiation, it is pretty safe to say that wild caught fish from the Pacific Ocean are effectively contaminated to the point that the potential health benefits from their consumption are outweighed. Even if one had the naïve assumption that fish quality is unaffected by these environmental conditions, there is a well-known and thoroughly proven biological phenomenon that happens in the animal kingdom. Animals that are higher up on the food chain accumulate the toxins from the species they consume and their tissues develop higher concentrations of these toxins, typically 10x the amount of the species beneath them. This is also true for marine life. Larger fish species like swordfish and tuna, tend to have much higher amounts of and concentrations of toxins in their tissues compared to smaller fish and fish that they consume. This phenomenon is called bioaccumulation. This is another reason why one shouldn’t consume large amounts of fish, especially of the larger species.

Bioaccumulation is also a problem in fresh water fish species. While seafood is being thoroughly contaminated, freshwater fish are suffering in their own way. According to the World Water Development Report by the United Nations, global freshwater sources are being massively overexploited as well as contaminated from industrial and urban sources. Heavy metals from industrial waste runoff, landfill seepage, and fossil fuel emissions all make their way into the water supply. Namely lead, cadmium, arsenic, and mercury. Mercury contamination has become particularly widespread and is especially toxic because elemental mercury can turn into a more reactive form called methylmercury in the environment which increases its toxicity and its capacity to bioaccumulate in animal and human tissues. Fresh water fish are the organisms most affected, as well as the humans who consume them.

According to the California Office of Environmental Health Hazard Assessment, “…researchers have determined that the main target of methylmercury toxicity is the central nervous system.  At the highest exposure levels experienced in these poisonings, methylmercury toxicity symptoms included such nervous system effects as loss of coordination, blurred vision or blindness, and hearing and speech impairment.  The most subtle symptoms in adults are numbness or tingling in the hands and feet or around the mouth.  Scientists also discovered that the developing nervous systems of fetuses are particularly sensitive to the toxic effects of methylmercury…. … In recent studies of high fish-eating populations in different parts of the world, researchers have been able to detect more subtle effects of methylmercury toxicity in children whose mothers frequently ate seafood containing low to moderate mercury concentrations during their pregnancy.  The effects reported were slight decreases in learning ability, language skills, attention and/or memory in some of these children… Methylmercury builds up in the body if exposure continues to occur over time.  Exposure to relatively high doses of methylmercury for a long period of time may also cause problems in other organs.”

Methylmercury contamination is present in seafood as well.

pillsBesides heavy metals, a new type of toxin, which researchers are calling ‘micro-organic pollutants’, are now affecting fresh water supplies predominantly in America: prescription and pharmaceutical medications. A pilot study conducted by the EPA in partnership with Baylor University tested fish in various streams and rivers across the country, as well as from parts of the river that were close to waste water treatment plant discharges. The most common pharmaceuticals they found in fish tissues were anti-depressants, namely norfluoxetine and sertraline (Zoloft) possible side effects of which include:

  • Insomnia
  • Nausea
  • Fatigue
  • Diarrhea
  • Drowsiness
  • Tremor
  • Indigestion
  • Suicidal Ideation
  • Anorexia
  • Decreased Libido
  • Excessive Sweating
  • Ejaculation Failure
  • Agitation

  • Since wild fish are likely contaminated, is there an alternative? There are commercial agriculture facilities that develop seafood and freshwater fish. A basic caveat, however, is that just as there are quality and production differences among livestock farms, so too are there differences in fish farms. While the farming techniques for various species are different, the basic arrangement leads to common shortcomings. Fish are kept in close quarters environments, typically pens or containers which lead to several problems. Fish in close quarters produce more waste, and they are also more prone to disease and infections, and these are transmitted through the entire population more easily. The first problem of fish waste is often remedied by either redirecting the wastewater back into the environment or by filtering. The second problem is often remediated by pesticides and antibiotics. Often these measures are used preventatively even if no infection or contamination is visible.

    fish farmBecause many fish farms are actually just netted pens in bays and inlets of seawater and freshwater, pollution and contaminants that affect wild-fish are also present in farm-raised fish. A study conducted by Hites et al found that, “Having analyzed over 2 metric tons of farmed and wild salmon from around the world for organochlorine contaminants, we show that concentrations of these contaminants are significantly higher in farmed salmon than in wild. European-raised salmon have significantly greater contaminant loads than those raised in North and South America, indicating the need for further investigation into the sources of contamination. Risk analysis indicates that consumption of farmed Atlantic salmon may pose health risks that detract from the beneficial effects of fish consumption.”

    With all of this information, it may seem as if there are no clean and healthy sources of fish left. While it may definitely appear this way, there are responsible fish farmers are developing new and better ways to raise and harvest fish that preserve their health without harming the environment. Currently, these types of operations are cost-prohibitive because they require lots of energy to filter the water and maintain adequate nutrient levels. There are also problems with preventing and combating fish diseases and parasites without the use of pharmaceuticals. This requires constant monitoring and the quarantine of possibly affected fish which also greatly increases production costs.

    The bottom line is that the currently available supply of fish from commercial sources, both wild and aquacultured, are no longer clean enough to convey health benefits that outweigh their toxicity. Until such time comes that the responsible and healthy stewardship of fish species that are not contaminated either from environmental or man-made sources are once again available, recommending whole fish as part of healthy diet is not sage advice.

    Fish oil supplements on the other hand, are subject to different standards and typically through the manufacturing process are purified of contaminants. While it would be wonderful to say that all fish oil supplements are contaminant free, the truth is that quality control varies from manufacturer to manufacturer and there are definitely products on the market that are suspect. Before purchasing any fish oil supplement do some research and contact the seller and find out if they have any documentation or independent verification of purity and that their product is free of heavy metals and other common fish contaminants.

    As a final word of advice, you should probably avoid sushi, unless you order vegetable rolls.