Toxic shrimp cocktail, anyone? | Docs Talk | David Suzuki Foundation
Photo: Toxic shrimp cocktail, anyone?

By Lori Petryk, RD, MSc; and David Hadley, MD

"All animals are equal, but some are more equal than others." So claimed Napoleon the pig in George Orwell's classic novel Animal Farm. Napoleon could well have been talking about the differences between farmed and wild-caught shrimp.

David HadleyMuch like other farming practices, traditional aquaculture goes back thousands of years. Early shrimp farmers developed a balanced ecosystem where small numbers of shrimp coexisted in ecological harmony with other fish species. This type of early fish farming could yield about 200 kilograms of shrimp per acre in a good year. Today, high global demand for shrimp has led to the conversion of rice fields, salt beds and fishponds for industrial shrimp farms. According to a report by the U.S. public interest organization Food & Water Watch, today's corporate-run shrimp operations can produce more than 40,000 kilograms per acre. That's 200 times more shrimp per acre than the small traditional farms produced. As with many other industrial animal-farming operations, our ability to purchase this inexpensive food comes with hidden costs to our health and the environment.

Most industrial-scale shrimp producers rely on large doses of antibiotics and pesticides to reduce diseases and parasites in overcrowded shrimp pools. Although it is illegal for North American shrimp farmers to use antibiotics to control disease, it is not illegal in many other parts of the world. Most shrimp found in restaurants and grocery stores is mass-produced by numerous overseas suppliers. We rarely know where the shrimp we are eating has been farmed. The result is that we ingest an invisible shrimp cocktail of chemicals.

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Over the past 10 years, a number of salmonella outbreaks have been linked to antibiotic-resistant salmonella from shrimp farms in Asia. As a result, Thailand has banned the use of unsafe antibiotics in aquaculture. Has this solved the problem of imported toxic shrimp? An investigation on shrimp farming, conducted by students from UBC's Graduate School of Journalism, found that as recently as October 2010, shipments of shrimp from Thailand were turned away at the Canadian border for containing nitrofuran, an antibiotic shown in animal studies to have carcinogenic properties. The UBC investigation points out that the Canadian Food Inspection Agency (CFIA) only has adequate resources to inspect five per cent of imported shrimp.

The news is not all bad, though. According to David Suzuki's Sustainable Seafood Guide, good choices for shrimp include wild spot prawns caught in Canadian Pacific waters. Spot prawns are trapped, which minimizes the environmental damage we see with methods like net fishing, where many other marine animals are caught and killed along with the intended prawn catch. Because spot prawns are wild, there is little worry that they will be contaminated with antibiotics. And because they are low on the food chain, they contain little, if any, mercury and are safe enough even for pregnant women to enjoy two to three times a week.

What about cholesterol?

Long before we worried about possible environmental toxins in shrimp, people were concerned about the high cholesterol content of some shellfish. Cholesterol, a type of fat made in the liver of all animals, has important cellular functions and is a key component in our bodies' formation of steroids such as testosterone and vitamin D. This makes it essential for all animal life. But when excess cholesterol builds up in blood vessels over years, it can restrict blood flow to such critical organs as the heart and brain and increase the risk of heart attacks or strokes.

Although it was once believed that diets high in cholesterol contributed to this risk, it is now clear that our blood cholesterol levels are more affected by the amount and type of fat we consume, especially trans- and saturated fats, than the amount of cholesterol we eat.

A healthy diet can include some cholesterol-containing foods. In this context, spot prawns caught in the Canadian Pacific by trap, with their low-fat, high-protein and delicious taste, are an excellent choice that fits well into a healthy diet. Remember, moderation is still key, so rather than reaching for an extra serving of prawns, add an extra scoop of veggies to your plate. Your health and our oceans will be thankful for it!

Lori Petryk can be seen weekly hosting "Good for You, Good for Our Earth", a nutrition and sustainable food segment on SHAW TV. Dr. David Hadley is an emergency physician in Calgary, Alberta.

August 25, 2011
http://www.davidsuzuki.org/blogs/docs-talk/2011/08/toxic-shrimp-cocktail-anyone/

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