News on Wellness

Mercury Exposure Risk from Eating the “Wrong Fish”

Mercury exposure and fish For years, people have been educated about the benefits of eating fish. In fact, the Food and Drug Administration (FDA) along with the Environmental Protection Agency (EPA), proposed new guidelines specifically for young children and women in childbearing years. According to these two government agencies, most species of fish are safe but also a great source of protein and omega-3. However, there are also fish species when consumed in large quantities or too often, can actually be dangerous.

According to these guidelines, consumers are advised to choose fish low in mercury but it is important for people to know that regardless of species, all seafood contains some level of toxins. An occasional meal is fine but too much of these “wrong fish” can lead to nervous system and/or brain damage. The main concern is mercury, which can lead to impairment associated with sleep, speech, mobility, and motor function. In addition, high levels of mercury are responsible for people experiencing tingling sensations.

To ensure safety, the most recent proposal released by the federal government encourages pregnant women, those trying to conceive, and nursing moms, as well as children, to eat no more or less than between 8 and 12 ounces of fish weekly. This is the first in history that definite guidelines have been set for fish and shellfish consumption.

What does Consumer Reports Have to Say?

Because millions of people depend on information coming from “Consumer Reports”, this has become the best go-to place to learn about the real dangers of fish opposed to exaggerated claims. For starters, data provided by the FDA and used to measure mercury levels in certain types of fish was analyzed by food safety experts associated with Consumer Reports. From this information, nearly 20 specific choices of seafood were identified and deemed safe to eat several times a week, even by the select group mentioned above.

While these 20 choices raised no concern for mercury exposure when eaten according to the guidelines, the FDA’s the recommendation regarding the amount of tuna safe for children and women was disputed. In fact, experts with Consumer Reports strongly discouraged pregnant and nursing women, along with small children, to avoid eating tuna at all. Additionally, experts felt the FDA was not doing enough to help consumers choose the right low-mercury fish and shellfish.

According to Jean Halloran, director of food policy initiatives for Consumers Union, which works with both policy and advocacy for Consumer Reports, “We’re particularly concerned about canned tuna, which is second only to shrimp as the most commonly eaten seafood in the United States”. Experts explain that canned tuna is responsible for 28% of exposure to mercury for people in the US, primarily because of its popularity and mercury content.

To support its claims and explain rationale, the FDA sent out a statement in which they said their guidelines were based on a review of the latest science. Using scientific information, they concluded there was developmental and growth benefit in children when pregnant women, those trying to conceive, and nursing mothers, as well as children, eat more fish than usual. They also stated it was possible to increase the consumption of fish while at the same time having protection from the potential harmful effects of methylmercury found in fish.

Why is there Mercury in Fish?

When looking at different bodies of water, experts identified an approximate 30% increase in mercury over the past 20 years for the northern Pacific Ocean. However, researchers at both the United States Geological Survey and Harvard University agree the risk is likely to climb to 50% or even greater by the end of 2050 due to an increase in industrial mercury emissions.

The way mercury gets into fish is by eating small plants and animals that contain it. These fish are then eaten by even larger fish, whereby mercury accumulates in tissue. For this reason, toxin levels are much higher in big fish like tuna, swordfish, and sharks and much lower in smaller fish to include trout, sole, and sardines.

In 2014, a group of policy analysts and scientists pointed out in comments submitted to federal health officials that just one six-ounce serving of salmon contains approximately four micrograms of mercury opposed to a six-ounce can of tuna and swordfish that contain 60 and 170 micrograms, respectively.

Obviously, this is a serious problem but making matters worse is the fact that over 95% of methylmercury consumed in seafood is absorbed by the body and then passed through the bloodstream where it has the ability to penetrate virtually any organ and tissue.

What are the Safest Choices for Seafood?

This is not to say that people cannot enjoy fish, to include pregnant women, those wanting to conceive, nursing moms, and children, just that the right type of fish should be chosen. Following the dietary safety limit of methylmercury provided by the EPA, Consumer Reports came up with a list of the best fish choices to include examples like anchovies and clams. Other good options include scallops, shrimp, tilapia, oysters, squid, crab, and mullet.

Just as a list of recommended fish was provided by Consumer Reports, there is also a list of fish that should be avoided, especially those within the select group mentioned and people who consume fish on a more frequent basis. Some of the top fish to stay away from include shark, marlin, swordfish, king mackerel, and gulf tilefish. In addition, consumption of certain fish should be limited to include Chilean sea bass, halibut, black cod, Spanish mackerel, bluefish, grouper, and fresh tuna, excluding skipjack.

Understanding Limits

When the recommendations were made by the FDA and EPA in 2004, a limit of no more than 12 ounces of fish per week was advised due to risk of mercury exposure. Even though these government agencies still stand by that guideline today, they have also released minimum quotes for weekly consumption. Part of this new addition has to do with more recent research conducted by the FDA.

As stated by Dr. Stephen Ostroff, acting chief scientist for the FDA, ”The latest science strongly indicates that eating 8 to 12 ounces per week of a variety of fish lower in mercury during pregnancy benefits fetal growth and development”. However, beyond this added information, the guidelines for fish consumption have remained unchanged for the past decade.

Safety experts with Consumer Reports agrees all high-mercury seafood should be avoided by those women and children but more important, they also suggest no one should ever eat more than 24 ounces of fish weekly, especially fish with high mercury levels.

The current dietary safety limit set by the EPA for methylmercury is 0.1 microgram per kilogram of body weight per day. Therefore, the agency considers the maximum acceptable level at a blood level of 5.8 micrograms per every one liter of blood. Keep in mind, that guideline is more than 10 years old and since that time, a tremendous amount of research and studies have been conducted. As a result, experts from Consumer Reports, as well as others, strongly believe it is time for updated guidelines.

Deborah Rice who co-wrote the EPA document containing current levels in 2001, agrees by saying, “Based on newer studies showing harm from mercury at lower doses, there is no question that 5.8 micrograms is too high”. She goes on to recommend lowering the acceptable level to 2, possibly 3 micrograms of mercury for every one liter of blood.

Even with the current levels set by the EPA, there are a number of other agencies with real concerns this is still too much. As an example, one of the most recommendations is that it is perfectly safe for pregnant women to eat as much as six ounces of tuna a week.

Tata from the FDA pertaining to average mercury levels was analyzed by Consumer Reports’ experts. They found that eating just four ounces of albacore tuna a week by a 125-pound woman would cause the EPA’s safe levels to be exceeded. They also found limits would be exceeded if a child weighing 48 pounds consumed approximately 1.5 ounces.

Both the FDA and EPA claim light canned tuna is a good alternative since it contains a lower level of mercury. However, the National Fisheries Institute begs to differ. The reason, although canned light tuna, which accounts for about 70% of all canned tuna consumed in the United States, contains one-third of the mercury found in albacore tuna, it has almost twice as much the average level listed by the agencies for that particular type of tuna but in addition, testing showed that the highest level of mercury found in samples still exceeded the average level of mercury for fish like king mackerel.

A huge problem is that there is no way to determine high spikes in mercury in pregnant women and with mercury being potentially damaging to tissue and the brain of a fetus, this raises risk during the most critical developmental stage. A baby born healthy undergoes a lot of complex changes while in the womb, processes that must be done not only in the right sequence but at the right time. If an expectant mother consumed amounts of methylmercury considered unsafe, the growing fetus could experience permanent and irreversible damage.

The bottom line, pregnant women, those wanting to conceive, and nursing moms, as well as small children, need to choose only good fish and even then, eat in moderation.

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