Copper is an essential mineral for the body. Along with iron, it plays a vital role in the formation of Red Blood Cells (RBCs). It is a cofactor for several enzymes (cofactors are substances required for enzyme activation). Copper is a trace element - which means our body requires it only in small quantities. It is also crucial for organ functioning and a healthy metabolism. Meeting your copper requirements is important for the prevention of osteoporosis and cardiovascular diseases. The body cannot synthesize copper on its own - therefore, it must be consumed through diet or supplements.
Copper Metabolism and Absorption - Getting Technical
Hepatocytes - cells of the liver - are the primary sites for copper metabolism.
When copper enters the body through dietary sources, it is first absorbed by the intestines.
It is then transported to the hepatocytes by a tube-like structure called the portal vein.
The copper then enters the hepatocytes - this is mediated by a protein called copper transporter (CTR1). After it enters the hepatocytes, either of the two things happens:
1. With the help of another transporter protein ATP7B, it reaches the ‘Golgi apparatus’ (packages protein to transport it to the destination) where it binds to another protein, ‘apoceruloplasmin.’ Once copper binds to this protein, it becomes ceruloplasmin. Subsequently, this ceruloplasmin exits the hepatocytes and is transported to other organs.
Sometimes, the copper is loosely bound to another protein called albumin and is circulated in the blood. This is called free serum copper.
Free serum copper + ceruloplasmin = Total serum copper
These three parameters are very important for blood diagnostics of copper metabolism.
2. If the body doesn’t require copper, it is transported to the bile ducts. From there, it is excreted into the bile.
If the ATP7B protein doesn’t function well, the copper gets accumulated in the cells leading to Wilson’s disease.
Importance of Copper
Copper is found in the cells of almost all organs. It plays an important role in blood vessel formation, maintenance of the nervous and the immune system.
Our body needs copper for several activities. These include:
1. Formation and functioning of RBCs
2. Immune functioning - by forming white blood cells
3. Fetal and postnatal brain growth and development
4. Collagen formation
5. Turning sugar into energy
6. Protection from cell damage
7. Absorption of iron
8. Maintenance of healthy skin and connective tissue
Copper and Cardiovascular Health
Copper deficiency is associated with changes in lipid levels. According to animal studies, low copper levels can lead to cardiac abnormalities.
Some researchers believe that people with heart failure can benefit from copper supplementation.
Copper and Arthritis
Some studies have shown that copper may help delay or prevent arthritis. That’s why wearing a copper bracelet as a remedy for arthritis is popular.
RDA of Copper
For adolescents and adults, the RDA is about 900 mcg per day.
The upper limit for adults aged 19 years and above is 10,000 mcg, or 10 milligrams (mg) a day. An intake above this level could be toxic.
The copper requirement changes with age, gender, and events like pregnancy.
How Genes Influence Copper Intake?
SELENBP1 and Copper Requirements
The SELENBP1 is located on chromosome 1 and encodes selenium-binding protein.
Selenium is an essential mineral and is known for its anticarcinogenic properties, and a deficiency of it can result in neurologic diseases.
While selenium-binding protein has majorly been studied only for its tumor suppressant activities, a 2013 study found a significant association between this protein and erythrocyte (red blood cells) copper levels.
rs2769264 of SELENBP1 and Copper Deficiency Risk
rs2769264 is an SNP in the SELENBP1 gene. It is located on chromosome 1. This SNP has been associated with serum copper levels. According to a study, the presence of the G allele increases the copper levels by 0.25-0.38 units.
SMIM1 and Copper Requirements
The SMIM1 gene is located on chromosome 1 and encodes Small Integral Member Protein 1. This protein plays a vital role in the formation of red blood cells.
rs1175550 of SMIM1 and Copper Deficiency Risk
rs117550 is an SNP in the SMIM1 gene. This SNP has been associated with serum copper levels. People who have an A allele in this SNP are at a greater risk for copper deficiency - the presence of A allele decreases copper levels by 0.14-0.26 units.
Non-genetic Factors That Influence Copper Requirements
Breastfeeding
Infants fed on formula milk had lower copper levels than those on breast milk.
Excess zinc
Consuming excess zinc can lead to an inefficient absorption of copper.
Gastrointestinal (GI) diseases
GI conditions like celiac diseases, short-gut syndrome, and irritable bowel syndrome can impair copper absorption.
Certain health conditions
Some conditions, such as central nervous system demyelination, polyneuropathy, myelopathy, and inflammation of the optic nerve, can increase the risk of copper deficiency.
Symptoms of Copper Deficiency
Clinical symptoms of copper deficiency include:
- Premature hair greying
- Fatigue and weakness
- Sensitivity to cold
- Easy bruising
- Weak and brittle bones
- Learning and memory problems
- Pale skin
- Unexplained muscle soreness
- Loss of vision
Symptoms of Excess Copper
Copper toxicity means you have more than 140 mcg/dL of copper in your blood. It can be caused due to excess copper in drinking water, eating meals cooked in uncoated copper cookware, and IUDs (Intrauterine devices like copper-T).
Some symptoms of copper poisoning include:
- Fever
- Headaches
- Vomiting
- Diarrhea
- Yellow skin (jaundice)
- Dark stools
- Abdominals cramps
- Anxiety
- Mood changes
If left untreated, copper toxicity can lead to liver damage, heart failure, and in some cases, death.
Dietary Sources of Copper
Animal Sources of Copper
- Shellfish
- Oysters
- Organ meat
- Salmon
- Liver
- Lobster
Plant Sources of Copper
- Shiitake mushrooms
- Nuts and seeds
- Sweet potatoes
- Chickpeas
- Leafy greens
- Dark chocolate
Summary
- Copper is an essential mineral which is required for the formation of Red Blood Cells (RBCs) and healthy immune functioning. Studies have also indicated that adequate copper consumption can help prevent or delay cardiovascular diseases and arthritis.
- Liver is the primary site of copper metabolization with the involvement of 2 important transporter proteins - CTR1 and ATP7B. It is then circulated in a bound form as ceruloplasmin or as a loosely-bound form (free form) with albumin.
- Two genes, namely SELENBP1 and SMIM1, are involved in regulating copper levels in the body. The A allele in an SNP present in SMIM1 has been associated with reduced serum copper levels. People who carry the AA type may be at a greater risk of copper deficiency.
- Copper deficiency is recognized through symptoms like premature greying of hair, loss of vision, sensitivity to cold, easy bruising, and brittle bones. While lower levels of copper are dangerous, too much of it also can harm the body. Copper toxicity is characterized by anemia, mood swings, fever, headache, and vomiting.
- Copper requirements can easily be met through diet. Some dietary sources of copper include shellfish, oysters, Shiitake mushrooms, nuts, and dark chocolate.
References
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6034109/
https://pubmed.ncbi.nlm.nih.gov/10721936/
https://academic.oup.com/eurheartj/article/27/1/117/608121
https://en.wikipedia.org/wiki/Wilson%27s_disease
https://academic.oup.com/hmg/article/22/19/3998/571929
https://www.snpedia.com/index.php/Rs2769264
https://www.snpedia.com/index.php/Rs1175550
https://bmcpediatr.biomedcentral.com/articles/10.1186/s12887-015-0474-9%20
