Copper is a naturally occurring metal found in soil, water, and rocks. Copper is essential for our health. We need to get copper with our diet every day. In this article we will talk about the functions of copper in our body, how much copper we need to consume, which foods are rich in copper and what the symptoms are of too little or too much copper. And a bit of fun at the end: we’re going to talk about copper pans and copper pillowcases.
The main functions of copper
Copper helps to break down and absorb another metal, iron. Copper is important for the production of red blood cells.
In addition, copper is important for the production of collagen and therefore for connective tissue. Collagen is the most abundant protein in our body. Connective tissue is made of collagen. As the name implies, this type of tissue connects other tissues. It is an important part of bones, skin, muscles, tendons, and cartilage. It helps to make tissues strong and resilient.
Copper also supports brain development.
Copper is an antioxidant and is indispensable for the optimal functioning of the immune system.
Copper is also important for the production of pigment in our body. Therefore, structural copper deficiency can lead to premature grey hair and skin hypopigmentation. This is a condition where the skin is lighter in colour than normal.
How much copper do we need?
Copper enters our body mainly through food and is absorbed in the small intestine.
The preserved amount of copper in our body is about 100 mg, 50% of which is stored in the bones and muscles, 15% in the skin, 15% in the bone marrow, 10% in the liver and 8% in the brain.
The absorption of copper in the body is self-regulated. You absorb it better if your diet does not contain a lot of copper. And vice versa, if there is a lot of copper in your diet, copper is absorbed less efficiently.
In the Netherlands, the recommended dietary allowance (RDA) of copper for adults is 0.9 mg per day.
For a safe intake of copper, the upper limit of 5 mg (for adults) per day has been set by the European Food Safety Authority (EFSA).
Copper deficiency is rare in healthy people. It mainly occurs in people with genetic disorders or malabsorption problems such as Crohn’s disease and celiac disease. A genetic condition called Menkes disease interferes with copper absorption, leading to a severe deficiency that can be fatal without copper injections.
It is possible to create a copper deficiency by taking high doses of zinc supplements that can block the absorption of copper in the small intestine. This already happens at the dose of 40 mg zinc. It is therefore recommended to take 1 mg copper for every 40-50 mg of supplemented zinc.
A severe deficiency of copper leads to anaemia, hypopigmentation, hypercholesterolemia (too much cholesterol in the blood) and osteoporosis.
Too much copper?
People with rare Wilson’s disease have too much copper in their bodies.
For healthy people, chronic exposure to high levels of copper can lead to liver damage and gastrointestinal symptoms such as abdominal pain, cramps, nausea, diarrhoea and vomiting.
Tap water can be a source of copper. It is caused by leaked copper from old, corroded household pipes and faucets. The amount of copper you can get from tap water varies widely (ranging from 0.0005 mg/L to 1 mg/L). The risk of too much copper is greater if the water stagnates in pipes due to insufficient use. It can also be caused by using hot tap water (copper dissolves more easily at higher temperatures).
Best food sources of copper
- Cashews, 25 g: 0.55 mg copper;
- Whole wheat pasta, 100 g: 0.50 mg copper;
- Dark chocolate, 70-85% cocoa, 25 g: 0.47 mg copper;
- Sunflower seeds, 25 g: 0.45 mg copper;
- Mushrooms, 100 g: 0.32 mg copper;
- Whole wheat bread, 100 g: 0.23 mg copper;
- Potato, baked, 100 g: 0.22 mg copper;
- Almonds, 25 g: 0.22 mg copper;
- Tofu, 100 g: 0.20 mg copper;
- Avocado, 100g: 0.17mg copper.
What about copper pans?
In principle, store-bought copper pans are safe to use. The inside lining must then be made of stainless steel. This way the copper does not end up in the food. Old pans (such as those from your grandmother’s time) often do not have such a protective layer. And therefore, the risk of ingesting copper through food is higher.
Check your pans for stains and cracks that can make the metal thinner. If a copper pan is leaking, you can sometimes taste the metallic taste in your food. In that case you must throw this pan away.
Do not bring acidic foods into contact with copper as they can cause copper to dissolve into the food. Acidic foods include vinegar, citrus fruits, fruit juice and wine.
And what about copper pillowcases?
So-called copper pillowcases have been on sale for about ten years now. The claim is that when the skin comes into contact with the pillowcase, the copper fibers release copper ions into your skin. The copper ions are absorbed by the skin: they enter the skin cells and contribute to the production of collagen. This reduces wrinkles.
I actually have found a scientific article, reviewing all the known studies on copper pillowcases. In all the studies the authors reviewed, half of the research participants used pillowcases containing copper oxide, while the other half used similar pillowcases that did not contain copper oxide. The participants used the pillowcases during sleep for 4 or 8 weeks. In all studies, a significant reduction of wrinkles and crow’s feet occurred in the group that slept on copper pillowcases. Sounds like proof to me.
I searched the internet. The copper pillowcases cost 25 euros per piece on average. I might as well try it out soon. Will keep you updated!