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Vitamins & minerals health centre

Magnesium

Magnesium is a mineral that's important for the body to turn food into energy and for bone health.

Although magnesium is available in supplements, most people should be able to get all the magnesium they need from a healthy balanced diet.

Magnesium uses

Experts say that many people do not eat enough magnesium-rich foods. This mild magnesium deficiency could put them at risk of a number of diseases.

For instance, there is some evidence that eating foods high in magnesium and other minerals may lower blood pressure. Magnesium supplements may help some people with heart disease, but the British Medical Journal cautions "We need bigger studies to find out for certain if taking magnesium can help to reduce blood pressure."  Type 2 diabetes is also associated with low magnesium.

Intravenous or injected magnesium is used to treat other conditions, such as eclampsia during pregnancy and severe  asthma attacks. Magnesium is also the main ingredient in many antacids and laxatives. 

Severe magnesium deficiencies are rare. They are more likely in people who:

  • Have kidney disease
  • Have Crohn’s disease or other conditions that affect digestion
  • Have parathyroid problems
  • Take antibiotics or drugs for diabetes or cancer
  • Are older adults
  • Abuse alcohol

Doctors sometimes suggest that people in these categories take magnesium supplements.

Magnesium intake

Men need 300mg a day of magnesium, Women need 270mg a day.

Taking more than 400mg of magnesium can cause diarrhoea.

Magnesium food sources

Natural food sources of magnesium include:

  • Green, leafy vegetables, such spinach
  • Nuts
  • Brown rice
  • Wholegrain bread
  • Fish
  • Meat
  • Dairy food

Whole foods are always best. Magnesium can be lost during refinement and processing.

Magnesium supplement information

Magnesium comes in many forms. Magnesium is in multivitamins, antacids and laxatives. Doctors also give magnesium intravenously or by injection. As with any supplement, keep magnesium in a cool, dry place, away from humidity and direct sunlight.

Magnesium warnings

  • Side-effects. Magnesium supplements can cause  nausea, cramps and diarrhoea.
  • Interactions. Magnesium supplements may not be safe for people who take diuretics, heart  medicines or antibiotics.
  • Risks. People with diabetes or intestinal disease should not take magnesium without first consulting a doctor.
  • Overdose. Signs of a magnesium overdose include nausea, diarrhoea,  low blood pressure, muscle weakness and  fatigue. At very high doses, it can be fatal.

 

WebMD Medical Reference

Medically Reviewed by Dr Rob Hicks on August 14, 2013

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