It is necessary to take magnesium seriously. It is an essential mineral, but many people receive less than the recommended 300-400 mg per day. Before the industrial revolution it was common to receive 500 mg magnesium daily on average through the diet (some say 100 mg). Today we receive an average of under 250 mg.
In recent years, many reports have made a connection between magnesium deficiency and asthma and allergy. For example, in 1994 an English study showed that the more magnesium asthmatics received, the better their lung function became. Those who received 500 mg per day had a lung function which was 25% better than those who receive 400 mg, where lung function was determined as the amount of air that the participants could exhale in one second.
Asthma was not all that common in the past, but today it is a disturbingly common disease. Ca. one in every five children in the U.K. has suffered from asthma. The frequency of asthma cases has increased dramatically since the 1970s, and so far there have been few explanations to this increase. It is possible that magnesium deficiency could be a part of the cause.
During an asthma attack the bronchial tubes contract so that air has difficulty entering or, more importantly, leaving the lungs. As early as 1912, the famous doctor Trendelenburg (he was the doctor who discovered that raising the legs over the head in the event of a fall in blood pressure is beneficial) discovered that magnesium can dilate the bronchial tubes. He discovered this effect in research done on cows, but the same effect was demonstrated in humans in 1936.
Even so, there have only two randomised studies have been done to examine the effects of magnesium on asthma. The first of them, from 1997, showed that magnesium reduces asthma symptoms. The second, from 2003, was inconclusive, possibly because the participants in this study received so much medicine that there was nothing to improve.
Less allergy
Recently a group of Brazilian doctors have done a third study. They examined 37 children and young adults (7-19 years old) with persistent moderate asthma and allergy. They all received medical treatment in the form of an asthma inhaler containing a bronchial dilatory drug as well as steroids. They also had an inhaler with a fast acting bronchial dilator to be used in case of an acute worsening of their symptoms.
In 18 of these children, this treatment was supplemented with 300 mg magnesium daily for a period of two months. The rest of the group received a placebo. Who got what treatment was determined by lottery.
The magnesium helped. Those who received magnesium had substantially fewer days with worse than normal asthma symptoms than the group which did not receive magnesium (12 vs. 17 days). They also had fewer days where they needed the acute asthma spray (7 vs. 12 days). Even though this was a small study, the differences between the groups were statistically certain. The participants treated with magnesium also had a lesser reaction to the skin test used to test for allergy. They had actually become less allergic! The researchers could also see that the bronchial mucous membranes in the treated participants were much less irritated than before the treatment.
The conclusion was enlightening. Trendelenburg’s discovery holds up to scrutiny. But magnesium is a very cheap mineral which cannot be patented, so it is hard to find anyone who will pay for further research.
Niels Hertz
References:
- Gontijo-Amaral C et al. Oral magnesium supplementation in asthmatic children: A double-blind placebo controlled trial. European Journal of Clinical Nutrition 2007: 61:54-60.
- Britton J et al. Dietary magnesium, lung function, wheezing, and airway hyperreactivity in a random adult population. Lancet 1994;344:357-62
