What is copper and why is it in your blood?
Yes, copper is naturally present in your blood, but not in its free form. It is a trace mineral crucial for many bodily functions, but in a regulated and controlled manner. After dietary copper is absorbed in the small intestine, it travels to the liver, where it is bound to a protein called ceruloplasmin. This ceruloplasmin is then released into the bloodstream, acting as the primary vehicle for delivering copper to various tissues and organs throughout the body. Very little free, or unbound, copper exists in healthy individuals.
The essential functions of copper
Copper's widespread importance stems from its role as a cofactor for numerous metalloenzymes that facilitate single electron transfer reactions. These enzymes perform critical tasks, including:
- Enabling iron metabolism: Copper-dependent enzymes are necessary for iron absorption and its transport to red blood cells, which is vital for hemoglobin creation. A copper deficiency can therefore cause a form of anemia.
- Maintaining the nervous system: Proper copper levels support brain development and the health of the nervous system. Imbalances can lead to neurological issues like numbness, tremors, and loss of coordination.
- Supporting immune function: Copper is involved in immune system processes, and low levels can result in frequent infections due to a reduced white blood cell count.
- Forming connective tissue: Enzymes that depend on copper are essential for cross-linking collagen and elastin, which maintain the integrity of bones, skin, and blood vessels.
- Producing energy: Copper is a component of cytochrome c oxidase, an enzyme critical for cellular energy production.
Causes of imbalanced copper levels
Maintaining the right balance of copper is paramount. Both insufficient levels (deficiency) and an overabundance (toxicity) can lead to serious health complications.
What causes low copper?
Copper deficiency, also known as hypocupremia, is relatively rare but can occur from various causes, including:
- Malabsorption: This can result from gastrointestinal conditions like celiac disease or from prior weight loss surgeries that interfere with nutrient absorption.
- Excessive zinc intake: High doses of zinc can compete with copper for absorption in the intestines, leading to a functional copper deficiency.
- Inherited disorders: Menkes disease, a rare X-linked genetic disorder, causes impaired copper transport and absorption, resulting in a severe deficiency despite adequate dietary intake.
- Malnutrition: Severe nutritional deficiencies can lead to low copper levels, especially in malnourished children or premature babies.
What causes high copper?
Copper excess, or toxicity, can also arise from different sources:
- Wilson's disease: The most common cause of genetic copper toxicity, this autosomal recessive disorder results from a mutation in the ATP7B gene, which impairs the liver's ability to excrete excess copper into bile. This leads to toxic copper accumulation in the liver, brain, and other organs.
- Environmental exposure: Over-consumption of copper from contaminated drinking water (e.g., from old copper pipes) or using corroded copper cookware for acidic foods can lead to toxicosis.
- Supplements: In rare cases, very high doses of copper supplements can cause toxicity.
- Inflammatory states: Conditions like chronic infections, rheumatoid arthritis, or some cancers can cause elevated ceruloplasmin levels, which in turn increase blood copper.
Symptoms of copper imbalance: A comparison
Symptoms of copper imbalance vary depending on whether the levels are too high or too low. Some symptoms can overlap, making diagnosis challenging without proper testing.
| Symptom | Copper Deficiency (Hypocupremia) | Copper Excess (Toxicity) |
|---|---|---|
| Neurological | Loss of balance, difficulty walking, tingling limbs, cognitive impairment | Tremors, stiff muscles, problems with speech or swallowing, mood changes, anxiety |
| Blood-related | Anemia, neutropenia (low white blood cells), frequent infections | Hemolytic anemia (destruction of red blood cells), liver damage |
| Appearance | Pale skin, premature graying of hair, steely or sparse hair (Menkes disease) | Jaundice (yellowing of skin and eyes), Kayser-Fleischer rings (brown/green rings around eyes in Wilson's) |
| Other | Osteoporosis, bone fractures, fatigue, weakness | Nausea, vomiting, diarrhea, abdominal pain, liver damage |
How a blood copper test works
If a copper imbalance is suspected, a doctor may order a blood test, which typically involves a simple blood draw from a vein in your arm. The sample is analyzed for total copper and ceruloplasmin levels. A 24-hour urine collection may also be used to assess copper excretion. For definitive diagnosis of conditions like Wilson's disease, a liver biopsy to measure hepatic copper content may be required.
Interpreting your copper levels
Interpreting test results requires a comprehensive assessment by a healthcare provider, considering symptoms, family history, and other test results.
Normal serum copper levels for adults are typically between 63 and 158 micrograms per deciliter (mcg/dL). A low total copper reading, possibly accompanied by low ceruloplasmin, can indicate a deficiency or Menkes syndrome. In Wilson's disease, total blood copper is often low, but toxic copper accumulates in the liver and other organs, so this single test is not sufficient for diagnosis.
High copper levels may point to toxicity from environmental exposure, certain inflammatory conditions, or chronic liver diseases. It is crucial to discuss any abnormal results with a doctor to determine the underlying cause and the correct course of action.
Conclusion: The delicate balance of blood copper
Copper is an indispensable mineral that plays a central role in your metabolism, neurological function, and overall health. Its presence in the blood, primarily bound to ceruloplasmin, is a tightly regulated process. However, this delicate balance can be disrupted by genetic conditions like Wilson's and Menkes diseases, dietary factors, malabsorption, or environmental exposure. Understanding your risk factors and recognizing the signs of imbalance—from anemia and bone weakness in deficiency to liver damage and neurological issues in toxicity—is key. If you suspect a copper imbalance, seeking medical advice and appropriate testing is the only way to get a clear diagnosis and access lifelong management, which can involve dietary adjustments, chelation therapy, or zinc supplementation.
For more detailed information on mineral metabolism, refer to the NIH Office of Dietary Supplements website.
