Most people know that calcium is an important mineral but few realise that magnesium is equally important. In fact magnesium deficiency is more common. The majority (70%) of the population are low in magnesium. We only get about 10% of the magnesium we need from a typical modern diet.

Calcium is needed to contract muscle and magnesium is needed to relax it again. If you lack magnesium you can get muscle jerks, tremors and cramps. As the heart is the most important muscle, magnesium deficiency can weaken the heart leading to hypertension and abnormal heart rhythms. Magnesium is also known as nature’s tranquiliser because of its ability to relax the body. Lack of magnesium can cause anxiety, depression, and sleep disturbance. Other symptoms of low magnesium can be constipation, tingling and numbness, premenstrual tension and memory problems. Magnesium deficiency can worsen irritable bowel syndrome and asthma.

Magnesium is needed for 400 different enzymes in the body and without magnesium these vital pathways don’t work well.

Magnesium is difficult to measure and routine tests done at hospital (serum magnesium) are nearly useless as magnesium levels in the blood will stay normal until a person is nearly moribund. Basically, the body won’t allow magnesium levels in the blood to drop. Specialist labs such as Biolab ( can measure the far more useful red cell magnesium which measures magnesium inside the cell although this is rarely necessary.

The main source of magnesium is green, leafy vegetables (the greener the vegetable the more magnesium in it). Another good source is nuts and a handful of nuts each day can help keep magnesium levels up. However modern farming methods have left soils all over the world greatly depleted of magnesium. This means there is less magnesium in vegetables today and you need to eat more of them to keep your levels up. Diuretics (water tablets), PPIs (acid-blocking drugs: as the body cannot absorb magnesium without acid in the duodenum)) and alcohol can lead to magnesium loss. You also need more magnesium if you take a lot of calcium in the diet. This is a problem for milk drinkers as milk has lots of calcium but little magnesium.

Magnesium is not very well absorbed from the gut – in fact magnesium can act as a laxative. Epsom salts (magnesium sulphate) acts as a laxative when taken by mouth. However Epsom salts are well absorbed through the skin. A good way of obtaining magnesium is to put a cupful of Epsom salts in a hot bath and stay in for at least half an hour (avoid using soap and shampoos until the end of the bath). Because of the sulphur in it this will be like a spa bath (Epsom salts can be obtained from many chemists but you often have to ask as it may not be on the shelf). Magnesium is also absorbed through magnesium gels, sprays and oils which are widely available at health food shops.

Another way of obtaining magnesium is to use magnesium supplements. These can be quite big tablets as you need a lot of magnesium each day. Usually you would take about 2-300mg twice daily. Gradually increase magnesium until any muscle twitches disappear. When the stools start to get loose it usually means the body is saturated with magnesium and has enough. Supplements are available from any health food shop.