Magnesium deficiency: Causes, symptoms and prevention

1st August, 2019 • 7 min read

Magnesium is an essential nutrient that is needed for more than 300 enzymatic reactions in the body. Magnesium is used to regulate your nervous system, encourage the development of healthy bones, and maintain your blood pressure.

Magnesium is known to play an important role in maintaining blood glucose levels. If your body does not get enough magnesium, you may find that you feel tired, nauseous or weak. Low levels of magnesium are also associated with muscle cramps, seizures or abnormal heart rhythms, and there is a suggestion that chronic magnesium deficiency may be linked to a number of serious health conditions, including type two diabetes,

cardiovascular disease

Unfortunately, symptoms of low magnesium can be quite hard to spot.

In this article, you’ll find information about the causes and symptoms of magnesium deficiency, and information about the people who are most at risk of developing this condition. You will also find information that is designed to help you increase your magnesium intake.

How common is magnesium deficiency?

A recent meta-analysis of several population-based, cross-sectional studies found that approximately 10-30% of a given population may suffer from magnesium deficiency. There is also some suggestion that magnesium deficiency may be more common in high risk groups such as hospital patients, the elderly, and people suffering from

type 2 diabetes

If you are worried that you might be suffering from a magnesium deficiency, you should speak to your doctor straight away. They can help you diagnose the condition, and advise you on how to increase your magnesium intake.

You will also find information about increasing your magnesium intake at the end of this article.

What causes magnesium deficiency?

Some of the more common causes of magnesium deficiency include:

Gastrointestinal disorders

Magnesium is absorbed in the small intestine but your body can only absorb 30-40% of the magnesium present in your food.

Conditions that damage your small intestine and further reduce your body’s ability to absorb essential minerals may cause magnesium deficiency. This includes malabsorption syndromes like

Crohn’s disease
, Coeliac disease or short bowel syndrome, as well as conditions like steatorrhoea and
ulcerative colitis

Magnesium deficiency is also linked to chronic diarrhoea, which can reduce your body’s ability to absorb magnesium in the gut.

Certain medications

Some medications may also cause magnesium deficiency. This includes diuretics, digoxin, chemotherapy medications like cisplatin, certain antacids, and aminoglycoside antibiotics.

Some of these medications interfere with your kidney’s ability to absorb magnesium, while others may introduce trace amounts of metals like aluminium, which are known to interfere with magnesium uptake in the body.

The long-term use of proton pump inhibitors (PPIs) like omeprazole is also associated with magnesium deficiency.

If you are worried that your medication may be causing a magnesium deficiency, you should book an appointment with your doctor. They can test your magnesium levels, and may be able to prescribe an alternative medication if necessary.

Note: You should always consult with a health professional before you stop taking a prescribed medication.

Kidney diseases

Your kidneys are responsible for reabsorbing magnesium from your urine, and play an important role in maintaining your body’s overall magnesium levels.

Any condition that prevents your kidneys from functioning properly may cause magnesium deficiency. This includes conditions like

, pyelonephritis,
, nephrosclerosis, and renal tubular acidosis.


As we age, we see a natural decrease in our ability to absorb magnesium in the small intestines. Magnesium loss via the kidneys also increases with age, which means that elderly people are at higher risk of a magnesium deficiency.

Chronic alcoholism

Drinking too much alcohol may lead to the development of a magnesium deficiency.

A study published in The New England Journal of Medicine estimates that approximately one in three people with chronic alcohol abuse disorder will have a magnesium deficiency. This is because chronic alcohol abuse damages your kidneys, which may prevent you from properly absorbing magnesium.

Overconsumption of soft drinks

According to an article published in The BMJ, overconsumption of soft drinks may also increase your chances of developing a magnesium deficiency. This is because many soft drinks contain high levels of phosphoric acid.

Small amounts of phosphate are needed to maintain healthy teeth and bones, but high levels of phosphate in your blood can stop your body from absorbing magnesium and other minerals.

A low magnesium diet

Magnesium is found in a number of common foods, including spinach and other leafy green vegetables, almonds, peanuts, whole grains, and fortified cereals. Nevertheless, studies conducted in the UK, the United States, and Germany suggest that a certain proportion of people do not get enough magnesium from the food they eat.

A diet that prioritises heavily processed foods like polished rice, white bread, and processed cheeses has been linked to the development of magnesium deficiencies.

If you are worried that you are not eating enough magnesium-rich foods, please see your doctor to get a blood test.

Symptoms of magnesium deficiency

Mild magnesium deficiency may be asymptomatic, which means that you may not experience any readily noticeable symptoms.

That said, early symptoms of magnesium deficiency can include:

  • loss of appetite
  • nausea
  • vomiting
  • fatigue
  • weakness

Because magnesium plays an essential role in regulating your nervous system, magnesium deficiency can also cause numbness, tingling, muscle contractions and cramps, and seizures.

As magnesium deficiency progresses, it may also produce personality changes, abnormal heart rhythms, and coronary spasms. Long-term or chronic magnesium deficiency is also associated with

cardiovascular disease
type 2 diabetes
, and

If you are worried that you might have a magnesium deficiency, you should book an appointment with your doctor. They will be able to test your magnesium levels, and investigate any symptoms.

Increasing your magnesium intake

If you are worried that you may be suffering from a magnesium deficiency, you should book an appointment with your doctor straight away. They will be able to prescribe medications that will help to replenish your magnesium stores, and treat any related health conditions.

If you have been advised by your doctor to increase your magnesium intake, you will be pleased to know that magnesium is found in a number of common foods, including leafy green vegetables like spinach, legumes, nuts, seeds, and whole grains. Magnesium can also be found in some fortified cereals and breads.

The amount of magnesium you need to consume varies depending on your age and gender. As a rough rule of thumb, you should aim to eat foods containing approximately 300mg of magnesium if you are a man, and 270mg if you are a woman. Please see this government fact sheet for information about recommended magnesium intake for children and the elderly.

Some good dietary sources of magnesium are listed below, alongside their approximate magnesium content in mg (milligrams):

Food mg per serving
Almonds, dry roasted, 1 ounce 80
Spinach, boiled, ½ cup 78
Cashews, dry roasted, 1 ounce 74
Peanuts, oil roasted, ¼ cup 63
Cereal, shredded wheat, 2 large biscuits 61
Soya milk, plain or vanilla, 1 cup 61
Black beans, cooked, ½ cup 60
Edamame, shelled, cooked, ½ cup 50
Peanut butter, smooth, 2 tablespoons 49
Bread, whole wheat, 2 slices 46
Avocado, cubed, 1 cup 44
Potato, baked with skin, 3.5 ounces 43
Rice, brown, cooked, ½ cup 42
Yogurt, plain, low fat, 8 ounces 42
Oatmeal, instant, 1 packet 36
Kidney beans, canned, ½ cup 35
Banana, 1 medium 32
Salmon, Atlantic, farmed, cooked, 3 ounces 26
Milk, 1 cup 24–27

Note: Processed foods, including foods that contain refined (white) flour and polished (white) rice are likely to contain less magnesium than whole grain or unprocessed foods.

You may be able to obtain the magnesium you need by making small changes to your diet, and working to incorporate some of these foodstuffs.

Certain magnesium supplements may also interact with other medications that you are taking, so always consult with a health professional before taking one.

Important: Our website provides useful information but is not a substitute for medical advice. You should always seek the advice of your doctor when making decisions about your health.