The human body contains more copper than any other mineral, except iron and zinc, and has been known to be essential for both human and animal health since the earliest days of Western medicine. Yet even now the full range of copper's many functions is believed to be imperfectly understood, and researchers are still learning more. Copper principally acts within the body as a key component of many of the enzymes which govern its vital physiological processes and biochemical reactions. Perhaps most importantly, different copper dependent enzymes are vital for the production of energy within cells, for the production of collagen, a protein essential for the health and strength of the body's connective tissue, and for the metabolism of a number of important neuro-transmitting hormones within the brain and central nervous system.



More specifically, low blood levels of copper have been associated with anaemia, poor functioning of the immune system, and raised cholesterol levels, to name but a few. But nutritional therapists are most likely to recommend increased copper intake as a safeguard against the demineralisation of bones, leading to osteoporosis, and particularly in the treatment of rheumatoid arthritis. Copper is known to help in the body's production of superoxide dismutase, a powerful anti-inflammatory enzyme, which may well account for this effect; and there's evidence for the effectiveness of supplements of the safe compound, copper sebacate, and the wearing of copper wrist bands as alleviatory treatments. Copper is also important as an anti-oxidant, but care needs to be taken because both in excess and deficiency it can also function as a pro-oxidant, potentially accelerating the damage to and degeneration of the organism which may be caused by free radicals. Copper's interaction with zinc, one of the most vital minerals for human health, is particularly important in this context. High intakes of copper are associated with deficiencies of zinc, and the reverse is also true. High levels of copper, with low zinc, have been identified as a factor in correspondingly high levels of oxidised low-density lipids (LDL), or "bad cholesterol"; a key risk factor for the development of atherosclerosis (hardening of the arteries), still one of the major causes of premature death in the West. And it's worth noting in this context that adequate amounts of both copper and zinc are required for the production of superoxide dismutase, one of the body's most important anti-oxidant enzymes. Low zinc levels caused by excess copper have also been associated with mental problems such as depression, anxiety and even schizophrenia.

Achieving the right balance of intake of the minerals is therefore crucially important and the ratio of 1, copper: 10, zinc is generally recommended. A similar relationship exists between copper and iron, with an excess of one leading to a deficiency of the other; both excess and deficiency having potentially serious long-term consequences for health. Copper dependent enzymes are also closely involved in the metabolism of vitamin C, and there is some, though inconclusive, evidence that high intakes of the vitamin may increase the body's demand for copper. This is not to suggest that vitamin C intake should be restricted, because the health benefits of this nutrient are far too powerful for that. But it is yet another example of the body's holistic functioning; meaning that it is rarely if ever a good idea to supplement with high doses of a single nutrient, and that attention needs always to be paid to obtaining a balanced and comprehensive supplementation programme. A wide variety of foods are useful sources of dietary copper, but the problem is that the richest ones, liver and shellfish particularly, are foods which not everyone finds easily palatable or accessible. Nuts and pulses, whole-grain cereals and green vegetables may also provide a certain amount, but levels have been badly affected by the demineralisation of farm soils. A further problem is that dietary copper is often poorly absorbed, particularly when the diet is high in refined carbohydrates or artificial sweeteners.

The risks of copper toxicity appear to be low, although prolonged high doses may sometimes give rise to liver problems. The US Food and Nutrition Board has therefore prescribed an upper safe limit of 10 mg per day for copper consumption. Some authorities, however, argue that the potential pro-oxidant action of copper, and its interaction with other vital minerals, particularly zinc, makes this limit too high for safety; and certainly for optimal health. That said, the US Recommended Dietary Allowances (RDA) for copper of just 2 mg has, like all RDAs, been set only at the level judged sufficient for the avoidance of outright deficiency and is almost certainly well below the level required for optimal health. European authorities have not set an RDA, but figures for the UK suggest that average copper intake may be as low as 1.6 mg, with the corollary that 50% of the populace fails to achieve even this low figure. Figures for the US are likely to be similar, and the presumption must therefore be that most people in the West are far more likely to suffer from a deficiency than an excess of copper.

The potentially harmful interaction with other minerals means, however, that any supplementation of copper should be undertaken only as a part of a comprehensive multi-mineral and multi-vitamin regime.