Magnesium Deficiency


In A Fundamental View of IBS we saw how the signs and symptoms of IBS can be derived from two fundamental anomalies: –

  1. The gut contracts abnormally.
  2. Normal gut stimuli are painful (visceral hyperalgesia).

We saw how abnormal gut contraction is part of a generalised smooth muscle disorder. IBS patients have hypersensitivity to chronic pain and visceral pain, not just pain in the gut. This pain is mediated by NMDA receptors which are part of the enteric nervous system. We hypothesised that an NMDA receptor disorder underlies the migrating motor complex abnormalities seen in IBS patients and combined with lowered NMDA thresholds results in abnormal motor activity.


Magnesium is an ‘intracellular cation’, it is active principally in the intracellular space, in contrast to calcium which is an extracellular cation. Most magnesium is in the skeleton with the remainder in soft tissue, primarily in muscle. Blood contains less than 1% of total body magnesium. Only the free, ionized form of magnesium (Mg2+) is physiologically active. It is not practical to measure magnesium status outside of a research facility, magnesium blood tests are of little use. A low serum ionised magnesium may indicate deficiency, but a normal result does not confirm sufficiency.

I initially became interested in the role of magnesium when I had IBS and noticed I would wake up with my teeth gently clenched, a sign of tetany. Some investigations suggested this may be ‘latent tetany’, an old description for magnesium deficiency. My serum ionised Mg was normal, just a little above average. My calcium level was fine, but I exhibited a positive Chvostek sign. I tried magnesium citrate for my IBS, it helped a lot but was not a cure.

We used to take holidays in Austria and afterwards my IBS would go away for four to six weeks. I ruled out stress as a cause because I didn’t get this benefit from holidays in other places. I thought it might be due to sunlight providing vitamin D. I tried supplementing with vitamin D and found it helped (vitamin D assists magnesium absorption). In retrospect vitamin D wasn’t the major reason for this improvement (this will be explained in the Hypothyroidism section). However, the beneficial effect of vitamin D supported my magnesium hypothesis and set the direction for my research.

I noticed that IBS attacks go through stages. The first sign is that my breathing feels stuffy with a slight runniness in my nose (I now put this down to bronchial hyperactivity). My abdomen then starts to bloat and become painful after a while. The following day or two I would feel abdominal discomfort like I had tenderness inside my gut, or the chyme was too acidic and I would produce ‘ribbon stools’. Eventually, it would all pass and the attack would be over.

I discovered that if I put a magnesium citrate tablet under my tongue as soon as I sensed the stuffy breathing, I could abort the IBS attack without any follow-on symptoms. This is crucial because it demonstrates that we only need to prevent the initiation of an IBS attack, we don’t need to investigate follow-on effects. The task of understanding IBS is simplified.

Next we look at why the gut contracts abnormally in Magnesium and Smooth Muscle.