Cancer Research UK cautious over minerals research
A new French study has suggested that raised blood levels of magnesium -most commonly found in leafy green vegetables - over a person's lifetime may reduce the long term risks of cancer and heart disease.
It also found that high levels of copper increased cancer risk, and that changes in zinc levels could modify the effects of the other two substances.
Cancer Research UK emphasised that the study only looked at a relatively small number of individuals, and did not show whether the levels of minerals were actually responsible for the effects or simply a result of having cancer or heart disease.
"Cancer Research UK is currently funding part of the European Prospective Investigation into Cancer and Nutrition (EPIC), the largest study of diet and health ever attempted," said Henry Scowcroft, senior science information officer at the charity.
"Nearly half a million participants have been recruited into the study, which is being conducted across ten EU countries. This should provide further insights into the role of these minerals in cancer risk, he added.
Zinc, copper and magnesium play a number of key roles in the body, for example in the immune response, inflammation and oxidative stress.
The study measured blood levels of the three minerals in 4,039 men between the ages of 30 and 60 over an 18 year period. During the study period there were 56 deaths from heart disease and 176 from cancer.
The men who had the highest copper levels in the blood at the beginning of the trial had a 50 per cent increased chance of death and a 40 per cent increased chance of dying from cancer compared to men with the lowest levels.
Those with the highest magnesium levels had between a 40 to 50 per cent reduced chance of dying compared to men with the lowest levels.
The researchers, from the Lille Pasteur Institute in France, said that much more work would be needed to clarify the effects of these minerals.
The research is published in the journal Epidemiology.