What Is the Main Idea?

Copper and zinc are essential trace nutrients that play important roles in the body. In the open-access case report “Copper Deficiency Mimicking Myelodysplastic Syndrome: Zinc Supplementation in the Setting of COVID-19”, published in the journal Case Reports in Oncology, the authors discuss how oversupplementing with zinc to prevent infection can cause copper deficiency, which can cause symptoms that are similar to a group of blood cancers called myelodysplastic syndrome.

What Else Can You Learn?

In this blog post, the roles of zinc and copper in the body, and the effects of not getting enough or too much, are discussed. The symptoms of myelodysplastic syndrome are also described.

Why Does the Body Need Copper?

Copper is classed as an “essential trace nutrient”, which means that the body needs small amounts to work properly. It is involved in important processes in the body that include making energy, absorbing iron, making red and white blood cells, keeping the immune and nervous systems healthy, making collagen (which plays an essential role in the structure and function of skin, bones, cartilage, and connective tissues), and brain development. It also acts as an antioxidant, which means that it is involved in reducing levels of molecules called “free radicals” that can damage cells and DNA, and that are produced in the body as part of its normal energy-producing processes.

How Do Our Bodies Get the Copper They Need?

Most people should be able to get all the copper their body needs by eating a balanced, healthy diet. Good dietary sources of copper include offal (such as beef liver), shellfish (such as oysters and mussels), nuts (such as cashews and almonds), seeds, chocolate, dark green leafy vegetables, legumes (beans and pulses), wholegrain breads and cereals, mushrooms, and sweet potato. Copper deficiency (defined as the levels of copper in a person’s body being too low to meet their body’s needs or that the level measured by analysis of a blood sample is lower than the normal range) is rare but can be treated. It usually affects people who have had some form of gastric bypass or intestinal surgery, or who have celiac or inflammatory bowel disease. This is because their bodies may be less able to effectively absorb copper from their food.

How Much Copper Is Enough?

As with any nutrient, too little or too much copper can be harmful to the body. Guidelines regarding recommended daily intake vary by country, but are generally between 0.9 and 1.6 mg/day. Too much copper can cause symptoms that include stomach pain, nausea, diarrhea, and dizziness, and kidney and liver damage can occur if levels are too high for a long time. In contrast, copper deficiency can cause symptoms that include fatigue, decreased production of blood cells, lightened patches of skin, weak and brittle bones, increased risk of infection, and neurological symptoms such as numbness or tingling, difficulties with muscle coordination and balance, and signs of vision loss. Importantly, copper deficiency can present in the same way as myelodysplastic syndrome and is an important differential diagnosis (a disorder that could be causing the symptoms being experienced) in patients in whom myelodysplastic syndrome is suspected.

What Is Myelodysplastic Syndrome?

Myelodysplastic syndrome (also known as myelodysplasia) is the name given to a group of rare blood cancers that result in a person not having enough healthy blood cells. This is because their bone marrow (the part of the body that makes blood cells) makes blood cells that are abnormal (they do not form or do not work properly) and unable to mature. Over time, the number of immature blood cells in the bone marrow increases, preventing it from making enough healthy, mature blood cells, and the number of mature blood cells that can get into the bloodstream decreases. Myelodysplastic syndrome can develop slowly or quickly, and in some people can develop into a type of leukemia called acute myeloid leukemia. Symptoms vary from person to person (depending on which type(s) of blood cell have become reduced in the bloodstream) and can include frequent infections, weakness, tiredness, pale skin, shortness of breath, bruising and bleeding, and anemia. If a person is experiencing these symptoms, it could be that they have copper deficiency.

How Is Copper Deficiency Linked to Zinc?

A number of studies have shown that copper deficiency can be caused by “zinc overload” (taking too much zinc into the body). This is thought to be because excessively high levels of zinc cause copper to be removed from the body at an increased rate while the rate at which it is absorbed is decreased. Like copper, zinc is an essential trace nutrient. It is involved in metabolism (the process by which the body produces energy), wound healing, your sense of taste and smell, and the immune system. However, like copper, too little or too much zinc can be harmful. Symptoms of zinc deficiency include hair loss, eye and skin sores, and diarrhea. In the short term, a very high dose of zinc can cause nausea and vomiting, headache, and stomach ache and diarrhea, while high levels of zinc over a long period can reduce levels of “good” cholesterol, cause copper deficiency, and prevent the immune system from functioning properly. This last point is important, because “over-supplementing” with zinc can cause zinc overload.

How Does This Relate to COVID-19?

Because of its role in the normal functioning of the immune system, some people began taking zinc supplements during the COVID-19 pandemic in an attempt to prevent themselves from getting infected. Zinc supplements can be bought over the counter and are widely available, and there were reports in the media that zinc (among other things) could help prevent COVID-19 infection and prevent the severity of symptoms. This has led to several case reports (a case report is a type of medical summary that outlines the signs and symptoms, diagnosis, treatment, and follow-up of an individual patient) being published that have described cases where patients have presented with symptoms that have suggested that they have myelodysplastic syndrome, but have instead been found to have copper deficiency caused by zinc overload as a result of taking high-concentration zinc supplements. In one case report, a woman had been taking eight times the recommended daily amount of zinc (which varies by country but is usually between 7 and 8 mg for women, and 9.5 and 11 mg for men) in an attempt to prevent COVID-19 infection.

The authors of this case report describe the case of a man who had no pre-existing gastric or stomach problems, who presented with myelodysplastic syndrome symptoms that were found to be caused by copper deficiency. He had taken a zinc supplement of 50 mg/day for 6 months to prevent COVID-19 infection, but had stopped taking the supplement 2 months before presenting to his healthcare provider. After being advised not to take zinc and being started on copper supplementation, some of his symptoms disappeared and others improved.

Take-Home Message

This case report emphasizes the importance of not oversupplementing. Most people are able to get all the copper and zinc, as well as other nutrients, that they need from a normal healthy diet. Good sources of zinc include meat, shellfish, poultry, nuts and seeds, wholegrains, and legumes, and most of these are also good sources of copper. If you choose to take supplements, check the label and make sure that you are staying within the recommended daily amounts for your country or region. If you take more than one supplement, check that their combination does not mean that you are taking more than the recommended daily amount for a particular nutrient. If you are concerned that you may have a nutrient deficiency, talk to your healthcare provider.

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