Copper deficiency is a very rare hematological and neurological disorder. The neurodegenerative syndrome of copper deficiency has been recognised for some time in ruminant animals, in which it is commonly known as ‘swayback’. The disease involves a nutritional deficiency in the trace element copper.
Copper is pretty much everywhere and daily requirement is low, therefore making acquired copper deficiency very rare.
Copper deficiency can manifest in parallel with vitamin B12 and other nutritional deficiencies. Copper is involved in the function of many enzymes, such as cytochrome c oxidase. These enzymes catalyse reactions for oxidative phosphorylation – a metabolic pathway that uses energy released by the oxidation of nutrients to produce adenosine triphosphate (ATP) – iron transportation, antioxidant and free radical scavenging and neutralisation, and neurotransmitter synthesis.
A regular diet contains a variable amount of copper, but may provide 5 mg/day, of which only 20-50% is absorbed. The diet of the elderly may contain a lower copper content than the recommended daily intake.
Dietary copper can be found in whole grain cereals, legumes, oysters, organ meats (particularly liver), cherries, dark chocolate, fruits, leafy green vegetables, nuts, poultry, prunes, and soybeans products like tofu.
The deficiency in copper can cause many hematological problems, such as myelodysplasia, anemia, leukopenia (low white blood cell count) and neutropenia (low count of neutrophils, a type of white blood cell that is often called ‘the first line of defence’ for the immune system).
Copper deficiency has long been known for as a cause of myelodysplasia (when a blood profile has indicators of possible future leukemia development), but it was not until recently in 2001 that copper deficiency was associated with neurological manifestations.
Some neurological manifestations can be sensory ataxia (irregular coordination due to proprioceptive loss), spasticity, muscle weakness, and more rarely visual loss due to peripheral neuropathy (damage in the peripheral nerves), myelopathy (disease of the spinal cord), and rarely optic neuropathy.
Because of its role in facilitating iron uptake, copper deficiency can produce anemia-like symptoms, neutropenia (a granulocyte disorder characterized by an abnormally low number of neutrophils), bone abnormalities, hypopigmentation, impaired growth, increased incidence of infections, osteoporosis, hyperthyroidism, and abnormalities in glucose and cholesterol metabolism. Conversely, Wilson's disease causes an accumulation of copper in body tissues.
Severe deficiency can be found by testing for low plasma or serum copper levels, low ceruloplasmin, and low red blood cell superoxide dismutase levels; these are not sensitive to marginal copper status. Explained in ‘The immune system as a physiological indicator of marginal copper status?’ by Bonham, M. et al. (2002), published in the British Journal of Nutrition, the ‘cytochrome c oxidase activity of leucocytes and platelets’ is another factor in deficiency, but the results have not been confirmed by replication.
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