Animal Seafood & Your Dinner Table

By J.M.S. Robertson

Most of us have heard references to the dangers of large, predatory fish such as swordfish, shark and tuna and correlating high levels of mercury, but is this all that a health-conscious domestic goddess has to worry about when making the weekly shopping list?

In actuality, there are numerous factors that come into play when questioning the health and safety issues surrounding a particular marine animal as a dietary choice:

• Where is the animal found?
• What is its life span?
• What does it primarily feed on, and how does it process its food?
• Do its tissues contain a high percentage of oil or fat?

Many of the finfish and shellfish that are commonly consumed as part of a standard, “healthy” American diet have not been tested for contaminants of any kind. As a vegan, this may be an issue that you feel is irrelevant to you, however, it never hurts to be prepared with a little bit of info when dealing with friends and loved ones when they ask you why you abstain from seafood. While it is true that fish are a good source of lean animal protein as well as healthy fats and oils in many cases, the current state of our planet’s marine environment certainly lends itself to a bit of examination when it comes to harvesting its living resources as a food source. Here are a few of the main areas of concern and how to best minimize the risk of over-exposure for those of you who may still choose to include seafood in your diet:

Metals
Heavy metals such as mercury and lead are currently hot topics when it comes to seafood. When contaminants are released into the air from industrial sources, they eventually find their way down into our water supplies through condensation and rain. Mercury is then transformed into a substance called ‘methylmercury’ in our oceans. As most animals (including humans!) have difficulty ridding themselves of heavy metals, these substances have a tendency to bioaccumulate, meaning that the body tissues of many marine organisms will contain metals in concentrations which are reflective of the contaminated sources which they have consumed over their lifetimes. For this reason, large, long-lived species which eat other long-lived species are most likely to have the highest amount of stored metals in their bodies. Examples of species most at risk include shark, swordfish, tilefish, king mackerel, and albacore tuna.

Pesticides
Agricultural pesticides frequently seep into water supplies including lakes, rivers, creeks and oceans due to terrestrial runoff from storm water or irrigation. Animals which may be affected include any commercially or recreationally caught fish or shellfish which live and feed in coastal and fresh waters, as opposed to the open ocean. Organochlorine and organophosphorous pesticide residues include substances such as DDT, which is commonly detected in food samples despite its ban from agricultural use in the US in 1972.

Pharmaceuticals
As the pharmaceutical industry for both humans and aquaculture continues to grow, medication concentrations in our seafood supply will also be on the rise. Pharmacological substances primarily find their way into rivers and streams through treated sewage water (most sewage treatment centers are not equipped to remove these chemical substances). In addition, diseases which plague fish farms are often combated with antibiotics or anti-parasitic medication, which can remain in seafood tissue long after they were administered.

PCBs
PCBs, or ‘polychlorinated biphenyls,’ are industrial compounds with uses including formulating lubricants, hydraulic fluids, and some plastic products. The use of these substances has been banned in the U.S., but they continue to be employed elsewhere in the world. Research has shown PCBs to be carcinogenic (cancer-causing). PCBs accumulate in the fatty tissue of finfish, as opposed to metals, which can be found throughout the tissues, including muscles and organs.

Dioxins
Dioxins are a group of chemicals which are normally formed as by-products of industrial activity, including waste-burning incinerators, production of PVC plastics and the chlorine-bleaching of paper, and are highly toxic to marine life and humans, linked to cancer and both developmental and reproductive problems. Generally, higher levels of dioxins are found in beef and dairy than in seafood, but avoiding DHA supplements made from fish oils unless they are tested and guaranteed to be free from heavy metals and have been distilled to remove chemical contaminants would be ideal. Another alternative are vegan supplements of omega oils extracted from marine algae, which are widely available for purchase at health food stores or online.

What to do if you just can’t kick the habit?
• Avoiding high-risk fish completely would be the best way to lower your chances of heavy metal poisoning, especially for pregnant women and young children.
• Knowing the source of your seafood will be helpful in avoiding pesticide-contaminated animals. Ideally, one should only purchase seafood from a reputable fish monger who can (and will) answer any questions you might have about where the food for sale is coming from. Checking for local advisories is also essential if you plan to participate in recreational fishing activities.
• There is not much that a consumer can do to avoid pharmaceuticals in the wild population, but buying farmed fish which has been tested and deemed safe to eat would be the best option if you do not choose wild stock animals when shopping.
• A good way to reduce your family’s seafood-related PCB intake would be to avoid some of the worst offenders (bluefish, Atlantic salmon and wild striped bass), remove as much of the fat or oil from your fish before cooking as possible, and choose steaming or grilling as a cooking option so that oils can drip away from the meat and be collected and discarded.

As always, research your food sources, arm yourself with knowledge, and then make your choices based on informed decisions according to what you and your family feel comfortable with and what makes sense with your lifestyle, your budget and the availability in your area.

Helpful links:
• Environmental Defense Fund’s Seafood Selector
• KidSafe Seafood Program
• Healthy Child Safe Fish Chart
• EPA Fish Advisories (U.S.A.)

Jennifer Robertson is a cephalopod biologist finishing up her PhD thesis while transitioning to a raw, vegan diet.  She has spent the last year living in Mumbai, India with her new husband and blogs about her experiences in maintaining sanity and health in the city of chaos at The Robertsons of Mumbai.