In terms of protein choices, tuna really has it going on: It’s typically low in fat and high in antioxidants and nutrients. However, all fish and shellfish are naturally exposed to some form of methylmercury in their lifetime before they make it to a can, sushi roll or grill. While mercury levels differ by the fish and the preparation, you may need to limit your tuna consumption. This is particularly true if you are pregnant, nursing or have small children, according to the U.S. Food and Drug Administration. Always ask your physician if you have concerns about the appropriate tuna servings for your individual health.
Mercury and Health Concerns
Mercury is an element produced as a by-product of pollution and also occurs naturally in the environment. When mercury goes from the air to rivers and oceans, it is called methylmercury. Chronic exposure to mercury is associated with a number of harmful health conditions and can cause birth defects in unborn children. While your body can remove methylmercury from your blood, it is a slow process, which is why limiting foods high in methylmercury is important to your health.
The longer a fish lives and the larger it is, the more likely it is to have higher levels of mercury. This is why the U.S. Food and Drug Administration recommends not eating shark, swordfish, king mackerel or tilefish. Some tuna types also have more mercury than others. For example, albacore or white tuna has more mercury than its canned, light counterpart. For this reason, you should not eat more than 6 ounces of albacore tuna per week.
Chunk Light Tuna
Chunk light tuna contains less mercury than its albacore counterpart. For this reason, you can typically consume more chunk light tuna per week than albacore. The Natural Resources Defense Council outlines the amount of chunk light tuna you can consume per week based on your weight. For example, someone who weighs 70 to 80 pounds should eat no more than one can -- about 6 ounces -- of chunk light tuna every six days. Someone 90 to 100 pounds should eat no more than one can of chunk light tuna every five days. An individual who weighs 110 to 130 pounds should eat no more than one can of chunk light tuna every four days, while someone weighing more than 140 pounds should not exceed one can of chunk light tuna every three days.
Tuna Steaks and Local Fish
Tuna steaks are another popular tuna preparation, but tend to contain higher levels of mercury than chunk light tuna does, according to the FDA. The FDA recommends eating no more than 6 ounces of tuna steak per week. If you are purchasing tuna fish locally, contact your state’s health department about mercury levels in nearby bodies of water. Some bodies of water have higher levels of methylmercury than others, meaning you may need to further restrict your dietary tuna intake.
Rachel Nall began writing in 2003. She is a former managing editor for custom health publications, including physician journals. She has written for The Associated Press and "Jezebel," "Charleston," "Chatter" and "Reach" magazines. Nall is currently pursuing her Bachelor of Science in Nursing at the University of Tennessee.