Heavy metal toxicity and fish
Seafood, and most prominently, fish, is not only an important source of protein, but also rich in essential minerals, vitamins, and unsaturated/essential fatty acids (EFAs). Yet it is just this nutrient-dense lipid content which can also pose the greatest harm.
Fish which contain the highest amounts of fat are potentially the most healthy (e.g., salmon, mackerel, herring, trout, sardines, and albacore tuna contain the highest amounts of EFAs). (1) But many of these same fish also can contain the highest heavy metal concentrations, specifically because heavy metals have an affinity for being sequestered in fat. Currently, some of the highest in methylmercury are king mackerel, marlin, orange roughy, shark, swordfish, tilefish, ahi tuna, and bigeye tuna. (2) In fact, it is recommended that women who are pregnant or trying to conceive avoid these types of fish. (3) Although the American Heart Association recommends eating fish at least twice a week to achieve recommended daily omega-3 fatty acid status, this can backfire if we aren’t careful about where we source our seafood, as well as which types we consume. (4)
The most famous heavy metal is mercury, which in its most harmful form is methylated. Methylation is a vital metabolic process which means that some carbon and hydrogen is attached to the mercury atom, making it more bioavailable to living organisms, such as fish swimming in the sea. Over time, then, this toxic methylmercury can concentrate in the fatty tissues of seafood via the ingestion of sediment, seawater, and oceanic food-chain organisms high in methylmercury. (5,6) One study found that fish muscles contained the least concentrations of heavy metals, while liver contained the highest amounts of copper, zinc, and iron, and gills contained the highest amounts of lead and manganese. (7)
Hence, it’s critical to eat sustainably harvested seafood, such as those provided by Vital Source Seafood, an inspiring company that only supplies sustainability certified fish and seafood (Marine Stewardship Council (MSC), State of Alaska, or Monterey Bay Aquarium SeafoodWatch program certified), such as wild-caught Alaskan salmon and northwest Pacific seafood, for a fair price and delivered flash-frozen to your doorstep.
Three foods that help your body remove heavy metals
The most famous herb for chelating heavy metals from the body is cilantro/coriander, or Coriandrum sativum, which has been specifically shown to help remove mercury, lead, and aluminum from the tissues. (8) Not only that, but it’s an immune-boosting herb.
2. Garlic and onions: Garlic, onion and shallot are sulfur rich foods which particularly help remove lead from the body. (9)
3. Brazil nuts: Brazil nuts contain high a
mounts of selenium, which has been shown to reduce metal toxicity. Selenium is critical for making the body’s most important antioxidant, glutathione, which protects from oxidative damage via an enzyme called gl
So why not cook sustainably harvested seafood with naturally chelating herbs, and feed two birds with one seed?! 🙂 I decided to sear a filet of wild-caught Alaskan Coho salmon with some of the ingredients mentioned above, and it came out wonderfully.
Recipe: Seared Coho Salmon with Cilantro and Brazil Nuts
¾ lb filet of wild-caught Alaskan Coho salmon
7 Brazil nuts, finely chopped
1 shallot, minced
Half a lemon
Freshly cracked pepper
Pinch of Maldon sea salt
Heat cast-iron skillet on medium, adding 1 tbsp. of coconut oil in cast-iron skillet. Lightly sauté shallot for 3-4 minutes, then remove from pan. Heat pan until very hot, then add ½ tbsp. more of coconut oil. Sear salmon fillet on both sides for 2-3 minutes, until underside is lightly browned, ending with skin side down. Plate salmon, cover in sautéed shallot, sprinkle with Brazil nuts and cilantro. Add seasoning. Squeeze lemon over. Voila! 🙂
- Fish and Omega-3 Fatty Acids. How Cigarettes Damage Your Body. http://www.heart.org/HEARTORG/HealthyLiving/HealthyEating/HealthyDietGoals/Fish-and-Omega-3-Fatty-Acids_UCM_303248_Article.jsp#.W1c9fthKg_U. Accessed July 24, 2018.
- Menon S. Mercury Guide. NRDC. https://www.nrdc.org/stories/mercury-guide. Published January 9, 2018. Accessed July 24, 2018.
- What You Need to Know about Mercury in Fish and Shellfish. WebMD. https://www.webmd.com/diet/mercury-in-fish#1. Accessed July 24, 2018.
Fish and Omega-3 Fatty Acids. How Cigarettes Damage Your Body. http://www.heart.org/HEARTORG/HealthyLiving/HealthyEating/HealthyDietGoals/Fish-and-Omega-3-Fatty-Acids_UCM_303248_Article.jsp#.W1c9fthKg_U. Accessed July 24, 2018.
Kohlstadt I. Fish, mercury, and personalized medicine. Townsend Letter: The Examiner of Alternative Medicine. June 2007.
How Does Mercury Get Into Fish? Scientific American. https://www.scientificamerican.com/article/how-does-mercury-get-into/. Accessed July 24, 2018.
El-Moselhy KM, Othman A, El-Azem HA, El-Metwally M. Bioaccumulation of heavy metals in some tissues of fish in the Red Sea, Egypt. Egyptian Journal of Basic and Applied Sciences. 2014;1(2):97-105. doi:10.1016/j.ejbas.2014.06.001.
The Health Benefits of Cilantro. Dr. Group’s Healthy Living Articles. https://www.globalhealingcenter.com/natural-health/health-benefits-of-cilantro/. Published February 16, 2017. Accessed July 24, 2018.
Negi, R., Satpathy, G., Tyagi, Y. K., & Gupta, R. K. (2012). Biosorption of heavy metals by utilising onion and garlic wastes. International Journal of Environment and Pollution, 49(3/4), 179. doi:10.1504/ijep.2012.050898.
Stockler-Pinto, M., Mafra, D., Farage, N., Boaventura, G., & Cozzolino, S. (2010). Effect of Brazil nut supplementation on the blood levels of selenium and glutathione peroxidase in hemodialysis patients. Nutrition, 26(11-12), 1065-1069. doi:10.1016/j.nut.2009.08.006
Ralston, N. V., & Raymond, L. J. (2010). Dietary selenium’s protective effects against methylmercury toxicity. Toxicology, 278(1), 112-123. doi:10.1016/j.tox.2010.06.004.