Magnesium is an essential nutrient used by every organ, and active in more than 300 chemical reactions in your body. It’s a key player in a wide range of processes in our bodies – from regulating muscle and nerve function, blood sugar levels and blood pressure, to making protein, bone and DNA.

Magnesium supplementation is also popular with folk that exercise regularly, as it’s believed to assist in the prevention of muscular cramps and spasms.

You’ll find magnesium in a wide range of foods

Most green vegetables, legumes, peas, beans and nuts are rich in magnesium, as are some shellfish and spices. Unrefined cereals provide a moderate amount of magnesium, though highly refined products contain very little.

Absorption of magnesium is quite adaptive to our diet – studies have demonstrated a rate of absorption at around 25% for folk following a high magnesium diet, while another found those with more limited intake absorb up to 75%.

That said, some diets and minerals may reduce the absorption of magnesium, for example:

While the best source of magnesium is food, the Bureau of Statistics' Australian Health Survey reveals about a third of adult Australians don't get enough magnesium. Because optimal levels of magnesium through the diet can difficult to obtain, the use of supplementation is popular – and effective.

It is worth noting while there's no upper limit to the amount of magnesium you can consume per day from food, research suggests the upper recommended dose for magnesium supplementation is 350mg a day – excessive intake can lead to diarrhoea and tummy upsets. Also note people with gastrointestinal or heart conditions, or diabetes should consult their healthcare provider before taking supplements. Also discuss any medications or supplements you are taking, as they can interact.

How much magnesium do you need?

The amount varies by age and gender - babies need 30mg per day, moving up to 75mg at 7-12 months (breastmilk is an excellent source of easily absorbed magnesium.) From one to three, 80mg is the RDI per day, increasing to 130mg from four to eight years of age. This jumps again to 240mgs from nine to 13 years old, then 360 to 410mgs per day by 14 through adulthood. By adulthood, males need 400mg per day until their hit their thirties, when it rises to 420mgs. Women require 310 mgs until their thirties, increasing to 320mgs thereon – except during pregnancy when it rises to 420mgs. 

Some lifestyle factors and health conditions can create magnesium deficiencies

Magnesium deficiency is rare, but can be caused by a poor diet, ongoing excessive consumption of alcohol, and some medications if taken over a long period of time – think fluid tablets and medicines for ulcers or reflux.  It’ s also linked to some health conditions, including type 2 diabetes or gastrointestinal issues.

The early signs of deficiency include loss of appetite, nausea, vomiting, fatigue, and weakness. If left untreated, numbness, tingling, muscle contractions and cramps, seizures, personality changes, abnormal heart rhythms, and coronary spasms may occur. Severe magnesium deficiency can lead to low serum calcium or potassium levels. If you’re worried about your levels, talk to your GP about a blood test.