Mercury Poisoning and Its Link with Seafood and Autoimmune Disease

Mercury poisoning is a medical condition caused due to too much exposure of the human body to mercury. Mercury is a type of elemental metal found in the earth’s crust and is toxic to human beings. A small amount of this metal may be present in our everyday food products, which may not negatively affect health.

But consuming too much mercury can be poisonous and result in mercury poisoning. Eating too much seafood can also be a cause of mercury poisoning because seafood contains mercury.

See also What Happens When You Eat Too Much Salt and Raw Vegan Sushi.

What is Mercury Poisoning?

Mercury poisoning is basically toxicity caused due to overconsumption of mercury, a metal that can come in contact with humans in many different ways. Some of the major reasons are: consuming a large amount of seafood and wearing certain kinds of jewelry.

The most common cause of Mercury poisoning is taking too much methyl-mercury or organic mercury, which is present in seafood. Mercury is a naturally occurring metal, but the amount of this metal has been raised to a dangerous level due to industrialization. Due to a large number of industries, this metal has made its way into soil and water and to animals like fish.

So consuming such foods can be a common cause of Mercury poisoning. Pregnant women and children may have more severe symptoms of this condition. But this toxicity can be prevented by limiting your exposure to this dangerous metal.

Symptoms of Mercury Poisoning

Mercury has been studied for many years due to its neurological effects. In fact, the Food and Drug Administration also said that too much mercury can cause some symptoms like:

  • Depression
  • Anxiety
  • Memory Problems
  • Irritability
  • Tremors
  • Pathologic Shyness
  • Numbness of mouth, hands, and feet

Some symptoms of Mercury poisoning build up over time. But a sudden onset of any of these symptoms could be a sign of toxicity, so consult your doctor to avoid any further complications.

Mercury poisoning Symptoms in Adults

If adults are suffering from advanced Mercury poisoning, they may experience the following:

  • Muscle weakness
  • Trouble walking
  • Lack of coordination
  • Difficulties and speech and hearing
  • Trouble walking
  • Vision changes
  • Nerve loss in face and hands

Mercury poisoning Symptoms in Infants and Children:

 Mercury poisoning can also affect fetal and early childhood development. If infants and young have high exposure to this toxic metal, they may experience a delay in their:

  • Fine Motor Skills
  • visual-spatial awareness
  • Speech and Language Development
  • Condition

Not only this but pregnant and nursing women should also avoid eating seafood with high mercury levels. Because, in this case, the mercury can be passed to the developing fetus in the womb of pregnant women or to the infant breastfeeding.

A complication of Mercury Poisoning

If mercury is consumed in a very large amount, it can lead to some long-term and sometimes permanent neurological changes. These side effects are notable mostly in young and developing children. In adults, mercury exposure can also lead to the development of the brain, which can result in a negative effect on development and learning and can cause disabilities.

According to Environmental Defense Fund, adults with higher mercury exposure may lead some life-threatening medical conditions:

  • Circulatory Failure
  • Permanent Brain Damage
  • Circulatory Failure

Fishes and Seafood: Major Cause of Mercury Poisoning

Seafood like fish is highly linked to mercury poisoning; this may be due to two reasons: Eating a certain type of fish may have a large amount of mercury or eating too much fish. These conditions can result in mercury poisoning.

Almost all types of fish have mercury; it comes from the water they live in. Large types of fish may have a higher amount of this metal because they eat small fish that already have mercury. But the concentration of mercury in seafood and fish is 1 to 10 million times that of the concentration of the water they live in.

Studies have also shown the effect of fish and seafood in increasing the mercury level of the human body. For example, one study (Stratakis, 2020), found out that the participants who eat fish less than once a week won’t have much mercury exposure. But the participant who eats 2-3 servings of fish per week has high levels of fetal mercury exposure.

That’s why the FDA recommends taking less than 2 servings of fish or seafood with low mercury levels for children under 11. The serving size can vary depending on the age of the children. For example, 1 ounce is recommended for ages 1-3, 2 ounces for ages 4-7, and 3 ounces for ages 8-10

Moreover, some territories, states, and tribes of the US have specific advisories about water resources where the fishes are caught and kept may be contaminated with mercury. So it is better to be aware of such advisories before consuming fish that is caught by your family, friends, or yourself.

word diagram of mercury poisoning and its effects

Fishes with Higher Mercury Level:

The fishes which may have a higher level of mercury are:

  • King Mackerel
  • Sharks
  • Swordfish
  • Tilefish
  • Marlin
  • Orange Roughy
  • Bigeye Tuna

Fishes and Seafood with Small Amount of Mercury:

It is also possible to get mercury poisoning by eating a large amount of seafood or fish with a low mercury level. According to the FDA, fishes with a lower amount of mercury are safe to eat for adults once per week. There are above 50 fishes and seafood which are in the category of lower mercury levels; some of the common names are:

  • Oyster
  • Shrimp
  • Squid
  • Mullet
  • Calm
  • Butterfish
  • White Fish
  • Salmon
  • Sardine

Moreover, anchovies, sole, hake, scallop, flounder, freshwater trout, canned white tuna,  Atlantic croaker and Mackerel, black sea bass, and catfish also contain low levels of mercury and are safer to eat.

Fishes and Seafood with Moderate Mercury Level:

There are certain seafood and fishes which have a moderate level of mercury in them and can be eaten by adults but in a very small amount:

  • Rockfish
  • Buffalo fish
  • albacore tuna
  • Bluefish
  • Carp
  • Snapper
  • Striped Bass

Moreover, some croakers, Mahi Mahi, monkfish, halibut, and Chilean sea bass, also have mercury in moderate amounts. But if seafood and fishes have a lower amount of mercury, it does not mean that it won’t cause mercury poisoning. So, always take care of the amount you are taking.

According to the FDA, the recommended amount of seafood for pregnant and breastfeeding women is only 2, or 3 servings of 4 ounces of fish or seafood with the lowest amount of mercury, in a week. And if the fish and seafood have a moderate amount of mercury, then the serving should be restricted to one per week.

Some Other Causes of Mercury Poisoning

Not only seafood or fish can be a reason for mercury poisoning, but there can be other causes as well, like environmental or exposure to any form of this metal, which includes:

  • Certain types of jewelry
  • Broken thermometer
  • Dental filling with amalgam
  • Household gold extraction or mining for gold
  • According to the FDA, certain skin care products have been marked illegally in the U.S.
  • Exposure to toxic air, like in industrialized communities

Diagnosis and Treatment of Mercury Poisoning

Certain symptoms can alert you to these conditions, but for proper diagnosis, there are a physical exam and specific tests like urinalysis, chest radiograph, and blood tests such as complete blood count, metabolic panel, and serum mercury levels.

Healthcare providers may ask some questions during diagnosis, like what symptoms you have. And about your lifestyle and dietary choices. If they suspect mercury poisoning, they may ask for additional tests to measure the mercury level in your body.

 The treatment depends upon the level of mercury in the body. If the level reaches a certain level, then doctors may recommend chelation therapy. Drugs or chelating agents are used to remove the toxic metal from the organs and make your body dispose of them. Some other procedures to reduce the amount of mercury in the body and gastrointestinal tract may involve:

  • Dialysis
  • Charcoal
  • Whole bowel irrigation
  • Transfusion

In cases with higher levels of mercury, the patients need long-term treatment to manage the side effect of mercury poisoning, like neurological effects. However, the best way is prevention and limit your exposure to this toxic metal.

If you eat a lot of seafood or fish, lower your intake and choose vegan protein. And if you have an environment or workplace linked with toxicity, then you should remove yourself from such an environment to prevent further side effects.

Exposure to Mercury, a Risk Factor for Autoimmune Disease

Mercury exposure not only causes mercury poisoning but Is the most significant risk factor for autoimmunity among women and childbearing age. Some findings that appear in “Environmental Health Perspectives” found that even a low level of mercury, considered safe, may be associated with autoimmune disorders. This condition makes the body’s immune system attack healthy cells. Almost 50 million Americans, predominantly women, are affected by this medical condition.

How Can Mercury Cause Autoimmune Disorder:

According to a Ph.D. professor in the Department of Internal Medicine (Somers, 2015), there is not much evidence about the reason why people develop autoimmune diseases. And a large number of cases are not linked to genetics. So studying the environmental factors helped to understand why autoimmunity happens and what should be done to improve health outcomes. As a result of the study, mercury exposure stood out as the main risk factor for autoimmunity.

Autoimmune diseases are also linked to other health conditions like inflammatory bowel syndrome, rheumatoid arthritis, lupus, Sjögren’s syndrome, and multiple sclerosis. According to a National Health and Nutrition Examination Survey, greater exposure to mercury is associated with a higher rate of autoantibodies, which leads to autoimmune disease. Most autoimmune diseases are characterized by autoantibodies, a protein that is made by the immune system when it does not understand the difference between its own tissues and harmful cells.

Many fishes are restricted to pregnant, nursing women and young children. According to the FDA and EPA, pregnant women can have only 12 ounces of fish with low mercury levels once a week. But fishes like king mackerel, tilefish, and swordfish should be avoided as these have a high level of mercury.

Research That Proves the Fact:

Mercury is a metal in the earth’s crust naturally, but when combined with other elements, it can cause harm to humans. When mercury is dissolved in water or soil, it combines with microorganisms and converts into methyl-mercury, which can be absorbed by fishes and jellyfishes.

Various types of research have shown links between mercury found in some seafood and autoimmune disorder among young children and women. For example, according to an author of one study, scientists are not sure about developing certain diseases like lupus, multiple sclerosis, rheumatoid arthritis, and others. But the large number of people suffering from autoimmune disease are mostly women and those with large consumption of seafood.

An article published on stated that higher exposure to mercury is linked with a higher rate of protein known as “autoantibodies proteins are produced when the immune no longer distinguishes between healthy cells and harmful cells.

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Mercury poisoning is a medical condition caused due to too much exposure of the human body to mercury, a metal in the earth’s crust naturally, but when combined with other elements, it can cause harm to humans. When mercury is dissolved in water or soil, it combines with microorganisms and converts into methyl-mercury, which can be absorbed by fish and seafood.

That’s why a major cause of mercury poisoning is the higher consumption of seafood or fish. Symptoms of Mercury poisoning build up over time. Some common symptoms are:

Depression, anxiety, muscle weakness, lack of coordination, and vision changes. But if this condition is not treated, it can also lead to some serious medical conditions.

Not only seafood or fish can be a reason for mercury poisoning, but there can be other causes as well, like environmental or exposure to any form of this metal, like wearing a certain type of jewelry or getting in touch with a broken thermometer. So, try to avoid anything they can get extra exposure to mercury, including fish and seafood.

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