Weighing the Risks and Benefits of Fatty Fish: Too Much Mercury or Too Little EFA
By Barbara Lock, MDMarch 09, 2010
In 1986, California adopted Proposition 65, the Safe Drinking Water and Toxic Enforcement Act, by ballot initiative. The proposition requires the Governor to publish a list of toxins known to the state of California each year. It is because of this proposition that you will sometimes see a warning label on solvents or paints warning that they contain ingredients "known to the State of California" to cause disease.
Consumption of fish and fish oil supplements are so important for pregnant women; they supply essential fatty acids that promote healthy fetal brain development. But both fish and fish oil supplements are under particular scrutiny because they can be contaminated with toxic chemicals and elements found in industrial run-off, such as mercury and PCBs.
Mercury is of particular concern because high consumption of mercury in foods, usually fatty fish, to a level 5 to 50 times the national US average, can cause neurologic damage in fetuses and infants.
And PCBs, found in high concentrations in Great Lakes fish, can also cause lifetime neurobehavioral abnormalities! What a catch-22!
Luckily, there are some fish that have historically low levels of mercury and PCBs, and fish oil supplements are generally tested and controlled for contamination with toxins. Schiff Nutrition International confirmed the safety of its fish supplements today; the level of PCBs in the supplements were well within safe limits. Fish and seafood that are generally recognized as safe to eat for pregnant women are shrimp, wild caught salmon, canned light tuna, pollock, and catfish.
Walnuts, flaxseed and canola oil also contain some essential fatty acids (EFA). Eggs from free range hens or those supplemented with EFA in the diet contain significant quantities of EFA. However, fish oil is the most efficient way to obtain EPA (eicosapentaenoic acid), and people who have higher consumption of fish and fish oil have a lower risk of heart disease, sudden death, stroke, have a reduced risk of preterm birth, better brain funciton, lower rates of alzheimers disease, depression, and macular degeneration (degenerating vision). Clearly, it is a mistake to avoid fish and fish oil, even during pregnancy.
So how does one balance the risk of toxin exposure and the risk of insufficienty essential fatty acids? Well, most Americans are probably getting about less than half of the minimum recommended allowance of essential fatty acids, and should increase their fish consumption to two servings a week, or take a supplement.
Salmon is the only low mercury fish that contains high levels of EPA and DHA, and should be the fish of choice for pregnant women. Pregnant women are actually advised to eat fish or eggs high in EFA three times a week!
Menu for a High EFA Day (with low toxins):
Breakfast: Poached Free-Range Egg with Banana-Walnut Muffin and a cup of Canteloupe (Rock Mellon)
Lunch: Chicken Salad Sandwich with a cup of sliced Strawberries.
Dinner: Poached Wild-Caught Salmon with a Side of Chinese Broccoli.
This menu will provide more than 5 grams of essential fatty acids in the course of the day, most from the salmon, but significant quantities from all of the other foods. The minimum recommended allowance for children, men, and pregnant women is 1.4-1.6 grams per day. Have a high EFA day once or twice a week and see how much better you feel!
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