Key facts
- Magnesium is a mineral that is essential for healthy muscles, nerves, bones and blood sugar levels.
- If you don't get enough magnesium in your diet over a long time, you may be at a higher risk of health problems such as heart attack, stroke, diabetes or osteoporosis.
- Severe magnesium deficiency can cause symptoms including numbness, muscle cramps and an abnormal heart rhythm.
- Foods high in magnesium include green leafy vegetables, legumes, nuts, seeds and wholegrains.
- How much magnesium you need depends on your age, sex and stage of life.
What is magnesium?
Magnesium is a mineral that is essential for healthy muscles, nerves, bones and blood sugar levels. If you don't get enough magnesium in your diet over a long time, you may be at a higher risk of health problems such as heart attack, stroke, diabetes or osteoporosis.
What does magnesium do?
Magnesium is needed for many processes in the body.
Magnesium is important:
- for muscles and nerves to work properly
- to keep blood sugar and blood pressure at the right level
- to make proteins, bone and DNA (genetic material)
What are the complications of magnesium deficiency?
Low levels of magnesium over time can lead to problems with the flow of other nutrients into and out of the body's cells, including calcium and potassium.
If you don't have enough magnesium in your body, you might have symptoms such as:
Severe magnesium deficiency can cause:
- numbness or tingling
- muscle cramps
- seizures
- an abnormal heart rhythm
People with magnesium deficiency are at greater risk of developing:
How do I get enough magnesium?
Magnesium is obtained from food or from a supplement. Foods high in magnesium include:
- green leafy vegetables
- legumes
- nuts and seeds
- wholegrains
How much magnesium do I need?
How much magnesium you need depends on your age, sex and stage of life.
See this table for magnesium requirements across the lifespan:
| Age | Magnesium recommended dietary intake (RDI)* (milligrams) |
|---|---|
| 0 to 6 months | 30 |
| 7 to 12 months | 75 |
| 1 to 3 years | 80 |
| 4 to 8 years | 130 |
| 9 to 13 years | 240 |
| 14 to 18 years | |
| Males | 410 |
| Females | 360 |
| 19 to 30 years | |
| Males | 400 |
| Females | 310 |
| 31 to 50 years | |
| Males | 420 |
| Females | 320 |
| 51 to 70+ years | |
| Males | 420 |
| Females | 320 |
| During pregnancy and breastfeeding | 310 to 400, depending on age |
Source: Eat for health
*Recommended Dietary Intake (RDI): is the average daily dietary intake level that is sufficient to meet the nutrient requirements of nearly all (97–98 per cent) healthy individuals in a particular life stage and gender group.
It's important not to have supplements with more than the recommended amount of magnesium, as this can cause diarrhoea, nausea or abdominal cramps. Extremely high levels can lead to an irregular heartbeat or cardiac arrest.
Read more about magnesium rich foods and when you may need to take supplements.
What if I am taking other medicines?
Magnesium supplements can affect the way your body absorbs some medicines, including bisphosphonates (osteoporosis medicine) and some antibiotics. If your doctor recommends a magnesium supplement, make sure they know about all the other medicines you take and check they won't interact.
Some prescription medicines used to treat acid reflux or stomach ulcers, and some diuretics can affect the levels of magnesium in the body.
Very high doses of zinc (usually taken in supplement form) can interfere with your ability to absorb magnesium.
If your doctor is concerned about your magnesium levels, they may test your levels with a magnesium blood test.
Resources and support
- Visit Nutrition Australia for information about healthy eating.
- Eat for Health has information and advice about healthy eating.
