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Sorry folks - Emily H especially but I don't know how magnesium helps in asthma. On one of my jaunts this morning I did look it up in a book in a charity shop(!) - exciting jaunts I have I know. The information was scattered through the book which was actually aimed at taking supplements. If I think it would help I would prefer to have it in food form if poss with my allergies.

Which will be the next question - Which foods are rich in magnesium.

Hope all are as well as possible Thanks SandiX

8 Replies

Hi Sandi,

Don't worry about asking questions - increasing your knowledge is often the first step towards improved asthma control.

I have included some information about intravenous and nebulised magnesium, as these are the main ways that magnesium is used in asthma, and help you to understand the whole picture, although I realise that your main question relates to dietary supplementation.

Magnesium is given intravenously in hospital during an acute severe asthma attack, when it acts directly on the airway smooth muscle in ways not fully understood, and causes bronchodilation. It’s generally given as a one-off dose that’s infused over 20 minutes or so; this can be repeated a couple of times. It’s very effective in this situation for some people (I know some people who describe it as their ‘wonder drug’) and less effective in others. It can have quite severe side effects when given in this way, such as low blood pressure and cardiac arrhythmias, although some people have no problems with it.

The evidence for its effectiveness in this situation is limited, and a lot of the literature only shows benefit in people whose CO2 has started to climb, which would be the late stages of a severe attack for most people, Nevertheless, the British Thoracic Society guidelines on managing acute attacks say that it should be used as a fourth line therapy if an acute attack fails to respond to steroids and nebulised salbutamol and ipratropium. They list it for use ahead of IV aminophylline, although some hospitals would still use IV aminophylline before magnesium if they are more familiar with it (personally, my protocol lists IV aminophylline first as I know I respond better to it from past experience).

Another route for giving magnesium in acute attacks that is currently being investigated is via nebuliser. There is an ongoing trial into nebulised magnesium sulphate in severe asthma, and there are also some people with brittle asthma who are on it as an unlicensed treatment outside of the trial. Anecdotally, again, some people do respond very well to it, although the trial is ongoing so there is not a lot of evidence for it at this point. The main disadvantage of nebulised magnesium is that there is no manufacturer at present who produces magnesium nebs – people who are on it must therefore mix it up themselves at home, and very precise measuring is required, as it can be very dangerous if the concentration is wrong. Obviously precise measurement can be difficult in an acute attack. Again, there can be significant side effects, and most people who have used it in this way would need to then go to hospital for observation and further treatment.

So now to consider dietary supplementation with magnesium. There have been a few trials looking at dietary magnesium intake and supplementation in brittle and non-brittle asthma: notably

Thorax 1999;54:115-118 ( February ), J C Baker, W S Tunnicliffe, R C Duncanson, J G Ayres. ‘Dietary antioxidants and magnesium in type 1 brittle asthma: a case control study’

Eur Respir J 1997; 10: 2225-2229, J Hill, A Micklewright, S Lewis, and J Britton

‘Investigation of the effect of short-term change in dietary magnesium intake in asthma’

The main conclusions from these studies have been that studies of the diet of asthmatics (particularly brittle asthmatics, who often have multiple food allergies) do seem to be deficient in key nutrients, particularly vitamins A and C and magnesium, when compared to other people. It has been postulated that this nutrient deficiency and reduced antioxidant activity might contribute to disease activity, although this has only really been suggested in brittle asthmatics and may not be generalisable to non-brittle asthma. Of course, the deficiency may be nothing to do with the underlying cause of the disease; there are many potential confounding factors and sources of bias in the trials.

There have been a couple of studies which have been prospective trials of supplementing the diet of asthmatics with magnesium; the results have been slightly disappointing in that although the supplementation did appear to reduce symptom scores, there was no objective change in bronchodilator use or in measures of airflow obstruction such as peak flow or FEV1.

Again anecdotally, quite a few of the people with brittle asthma on this board have tried magnesium supplementation, and while a couple of people have felt that it has helped, the majority seem to have seen no improvement. Generally, the feeling from most consultants (including two of the consultants from the above studies, Prof Ayres and Prof Britton, both of which I have seen in the past; and also including the difficult asthma team at the Brompton) is that if you have a good balanced diet then any sort of supplementation should not be necessary, although in people with a restricted diet due to multiple food allergies, it may be recommended.

Having said that, vitamin and mineral supplementation would appear, on the face of it, to be a fairly safe and well tolerated intervention for most people, provided that the Recommended Daily Allowances are kept to – vitamins and minerals can be as toxic as any other drug in overdose. I would certainly not wish to discourage anyone from trying it, with appropriate discussion with their healthcare team – there does seem to be little to lose.

Foods that are high in magnesium include leafy green vegetables, pulses, nuts, seeds, whole unrefined grains and fish.

Hope this helps, do feel free to ask if there is anything that you want clarifying



EmH have you been eating textbooks recently by any chance? (choc is nicer)How do you actually retain all that info?


I don't know really, Katherine, I'm used to having to memorise vast amounts of medical facts from doing my post-grad exams a couple of years ago!

I have oodles of references bookmarked and mini-essays saved on my hard drive so I can easily check out stuff that I can't quite remember ;)

Basically I'm just an asthma geek... sad, I know!

Chocolate is much nicer, isn't it... and high in potassium, and dark choc is moderately high in magnesium too!




recently took part in a magnesium trial....

hi this mayb of particular interest to Em H possibly from readin this thread?

Im very well known unfortunatly at my local a and e! They were doin a trial on brittle asthmatics who needed frequent hospital admissions. It was a double blind trial that u had an infusion and a nebuliser one of which could have been magnesium but both could hav been saline.

From experience having had magnesium several times on admissions before i can say wit almost 100 percent certainty i did not hav the iv magnesium as i usually get a very odd flushin sensation wit it-and this did not happen!

The nebuliser wasnt saline i dont think as this makes me cough! Im pretty sure i had the nebulised magnesium. Side effects i had were minimal but the bronchospasm did return very very quickly and the effects of the neb were very short lived. The medics wanted to unblind the trial at one point as my condition started deteriorating again. They gave animophyline instead tho.

The next few days post neb i had a very sore mouth and throat and lost my voice for 3 or 4 days. Not sure if this is a side effect of the magnesium or not but ive never experienced that post a bad attack before.

The study is based in sheffield and the results are due to be collected by the end of the yr. There is to be a paper written about the use of magnesium in severe asthmatics wit a result in discharge from a and e! As the aim is to be able to discharge patients witout havin to admit them overnight! Im not sure this will take off but wud love to believe one day it could!! Sorry 4 the long rambly post just thought some folks would like to no about up and comin research-im a scientist so these sortsa things interest me!!

Hope everyone is keepin well. Xx


Some mineral waters have high amounts of magnesium (I drank a lot when I spent a year in France - they didn't sell dilute juice and magnesium is supposed to be good for migraines).


kit kat - i was involved in setting up the trial and with writing the questionnaires that were sent out to some participants - did you get one? I know they were only given to some participants. I personally have only nebbed magnesium once and didn't tolerate it at all well and had quite similar effects as to u - short duration of response and sore throat but am very familiar with the iv life saver!


hi hops

I did fill in all the questions on form wen they sent it thro post. I am convinced it was nebbed mg i got as saline just makes me cough.

I personally felt that nebbed mg wasnt as gud as the iv mg. I ended up on icu wen on trial as it did deteriorate despite max treatment think if id had iv mg instead it wud hav helped more. Always respond to iv mg. Dont no if this is same 4 most of trial patients or not but i personally prefer the iv mg as it does hav a much better effect witout the side effects of nausea vomiting and sore throat wit loss of voice for several days.

Hope everyone is warm and well. Take care lv kat Xx


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