By medical nutritionist Dr Sarah Brewer, an expert in food, herbs and supplements
Magnesium is one of the most important minerals, and also one that is often lacking in the diet. Magnesium powers the ‘pumps’ that control how salts move in and out of cells, and is essential for nerve conduction, muscle relaxation, healthy bones, normal heart rhythm and just about every metabolic reaction in the body – including energy production.
Magnesium is obtained from wholefoods such as nuts and seeds (especially pumpkin seeds, Brazil nuts, almonds and cashews), dark green, leafy vegetables (especially spinach and Swiss chard), beans (especially soy, lentils and white beans), fish (especially mackerel), dried fruit (especially figs) and wholegrains (especially quinoa, millet, Bulgur wheat and brown rice). All the foods we know we should be eating more of for long-term good health anyway!
Drinking water can provide useful amounts of magnesium in hard water areas, and – good news – dark chocolate is also an excellent source. Unfortunately, food processing strips magnesium from food, so that average intakes are 323 mg for males and 228mg for females compared with the EU recommended daily amount of 375mg per day.
Magnesium deficiency can build up with time and lead to annoying symptoms such as constipation, sleep difficulties, constant tiredness, fatigue, weakness, muscle cramps, restless legs, migraine, pre-menstrual syndrome (PMS) and even palpitations. Lack of magnesium can also contribute to raised blood pressure and thinning bones.
Magnesium and longevity
People with good intakes of magnesium tend to live longer than those with low intakes, probably due to its effects on relaxing blood vessels to lower blood pressure, and protecting against abnormal heart rhythms. Data from 19 studies involving almost 533,000 people found that the risk of a cardiovascular event (heart attack or stroke) was 15 percent lower in those with the highest dietary magnesium intake and 33 percent lower in those with the highest blood levels of magnesium.
Magnesium is an effective laxative – a quality recognised by the Victorians who valued the use of Epsom salt. This is not necessarily a bad thing, and I usually recommend taking a magnesium supplement at night to promote a good night’s sleep, and encourage bathroom regularity next morning.
An EU safety review of magnesium concluded that doses of up to 400mg magnesium per day would not be expected to cause side effects, but some people are more sensitive to the laxative effect of magnesium than others.
Magnesium oxide is one of the most popular forms included in supplements as, gram for gram, it provides the most magnesium (600mg per gram). The oxide is less well absorbed than other forms, however, so it tends to have a greater laxative result. If you are sensitive, then magnesium citrate (which contains 113mg magnesium per gram) may suit you better.
The ‘gentlest’ form (because it contains the least magnesium) is magnesium gluconate (which supplies 58mg magnesium per gram).
Absorbing magnesium through the skin
You can also absorb magnesium through the skin, and magnesium oil, body butter and bath flakes are increasingly popular ways to boost dietary magnesium intakes.
About Dr Sarah Brewer
Dr Sarah Brewer is a medical nutritionist and an expert in food, herbs and supplements. She qualified from Cambridge University with degrees in natural sciences, medicine and surgery. After working in general practice, she gained a master’s degree in nutritional medicine. Sarah is a licensed medical doctor, a registered nutritionist and a registered nutritional therapist.
Subscribe to her newsletter to get a FREE 46-page PDF Do You Need A MultiVitamin? at nutritionupdates.subscribemenow.com.