Magnesium, the mineral your body needs

Magnesium is a mineral, one of those substances our bodies need in modest amounts but cannot make for themselves. It has to come from our diet, and although the quantities required are small, they are vital.

We hear a lot about magnesium. Many of us know it is essential, and that a balanced diet should cover our needs, yet the practical details — where to find it, what it actually does, what a deficiency might mean — often remain vague. That is why we have put together a profile of this indispensable mineral, so you can get the essentials and give your body enough for its day-to-day wellbeing. That is no small thing. Here is an overview of what magnesium does and how to get enough.

Magnesium has a central role in the body: it helps regulate nerve signalling, both within the nervous system and in the organs that receive these nerve messages. In other words, a lack of magnesium can show up in a variety of ways, but the signs are non-specific and can have many causes.

A lack of magnesium can produce signs, but they are non-specific: small twitches in the eyelid or lips, tingling in the hands and feet, numbness in the hands and feet, calf cramps, significant anxiety. Breathing difficulties or a feeling of tightness in the chest may point to respiratory or heart problems: do not dismiss them, and see a doctor.

Premenstrual symptoms are also sometimes mentioned — bloating, pain, irritability, tearfulness over little things — but they can have many causes and do not on their own confirm a deficiency. Significant stress or pregnancy can also change magnesium needs or status, without making it possible to conclude on their own that there is a deficiency. Some data suggest that oral contraception may affect magnesium status in some people; if this applies to you, speak to a healthcare professional. A diet based almost exclusively on refined cereals rather than wholegrains may also play a part. These are all situations in which you should ask a healthcare professional for advice, not self-diagnose.

How much magnesium do you need?

Our magnesium needs vary with life stage, sex and age. For the reference values that apply to you, it is best to use official guidance; recommended intakes depend on individual circumstances, especially during pregnancy. In the UK, NHS advice is a sensible starting point.

Some people, particularly those following restrictive diets or with increased needs, may find it harder to meet their magnesium needs through diet alone.

Repeated weight-loss diets can, in some people, make it harder to meet magnesium needs, because the foods that contain it are often cut out. Caution is especially important when such diets are combined with laxatives or diuretics: laxatives can increase digestive losses, while diuretics increase losses through the kidneys. In that case, it is better to speak to a healthcare professional than to continue alone.

Watching your weight is fine, but do it responsibly: if you lack confidence about food choices, consider seeing a dietitian.

Stress is also often associated with magnesium loss, and a vicious circle is possible because magnesium plays a role in nervous system function. The evidence on mood remains limited or conflicting, however, and magnesium never replaces medical advice or treatment.

Where to find it

Many foods contain magnesium, and, yes, we start with chocolate. This irresistible treat is a well-known source, although milk and white chocolate contain little: rely on dark chocolate, ideally one that is fairly rich in cocoa.

Next come soya, almonds, peanuts and walnuts, then starchy foods: lentils, white beans, sweetcorn, oats, wholemeal bread. These are among the useful sources, but their magnesium content varies with variety, preparation — raw or cooked, dried or fresh — and the composition table used.

Do not forget vegetables that provide a useful amount: spinach, avocados, potatoes, artichokes and parsley. So reach for your fork.

Bear in mind that too little magnesium is harmful, but too much is harmful as well; be sensible. There is no need to overdo supplements and similar products when you eat a varied, balanced diet. In addition, excess magnesium can cause serious health problems in people with kidney impairment.

Food supplements do not replace a varied, balanced diet and a healthy lifestyle.