Causes, Signs and Symptoms of Magnesium Deficiency

Magnesium Deficiency Symptoms


The beginning of our understanding of the role nutrients have on the human body can date back to 1550 BC, where a group of British sailors found that citrus fruits relieved the bleeding gums of the crew members, known as scurvy. Fast forward to the early 20th century, the compound in these citrus fruits was identified as vitamin C [1].

While it is common knowledge to consume plenty of fruits and vegetables to prevent vitamin C deficiency, the causes, signs & symptoms of other equally important nutrients are less known. One of these essential nutrients is magnesium.

Magnesium is an essential nutrient because the human body cannot make enough on its own to survive, therefore the mineral must be obtained by eating food or consuming supplements. Magnesium is responsible for over 300 metabolic reactions in the body, and plays an important role in muscle contraction, blood sugar regulation, heart and bone health [2].

How much magnesium do I need per day?

The amount of magnesium you need per day depends on your sex and your age. Health officials determine requirements for magnesium based on population studies, where the amount is estimated to meet the needs for up to 98% of healthy individuals.

It’s important to understand that the recommended daily intake is designed for people without medical conditions. If you live with a chronic condition or take certain medications, your magnesium needs can be higher or lower.

The recommended daily intakes of magnesium for healthy adults over the age of 18 are [3]:

  • 270 mg per day for women
  • 320 mg per day for men

Causes of magnesium deficiency

Not getting enough magnesium through diet

The most obvious, yet most common cause of magnesium deficiency is not eating enough foods high in magnesium each day.

Processed and packaged foods, like those from fast food restaurants or convenience snacks at the grocery store make up a large consumption of our energy intake during the day but are extremely nutrient poor.

For example, a national survey conducted in the UK found that 53% of foods consumed by the population are ultra-processed foods [4]. Similarly, it is estimated that 60% of adults do not meet their magnesium needs each day [5].

As magnesium is found primarily in unprocessed, whole foods like dark leafy greens, vegetables, fruits, whole grains, dairy products and lean meats, replacing processed foods with these unprocessed foods could drastically improve magnesium intake.

Older adults can also have a unique challenge when it comes to getting enough magnesium each day if they struggle with lower appetite. Sensations of hunger can decrease in older adults, leading to lower overall intake of foods each day including those that are rich in magnesium [6].

Decreased absorption, storage and increased loss of magnesium

As we age, our body changes the way we absorb and lose magnesium. In older adults, the digestive system becomes less efficient at absorbing magnesium through the small intestine.  The capacity of bones to store magnesium also decreases with age [6].

Alongside decreased absorption and storage of the mineral, older adults also increase the amount of magnesium lost in their urine [6]. Overall, older adults may need to consume more magnesium each day to keep up with the natural changes occurring in their body.

Consuming too much alcohol

While a glass of wine at dinner a few times of week can provide health benefits, consuming too much alcohol or having a chronic alcohol dependency can harm magnesium levels in the body [2].

Drinking too much alcohol can act as a diuretic for magnesium, meaning that a lot of the body’s magnesium will become lost through the urine. Over time, excessive alcohol intake can deplete the stores of magnesium found in the bones [2].

Sometimes, people also replace healthy meals and snacks with alcohol, resulting in less magnesium being consumed overall from the diet [2].

Medical conditions and medications

The relationship between medical conditions and magnesium deficiencies may be bi-directional. This means that a medical condition could increase the risk of magnesium deficiency, while magnesium deficiency may increase the risk of a medical condition.

The following medical conditions are associated with lower levels of magnesium:

  • High blood pressure
  • Heart disease and stroke
  • Type II diabetes
  • Osteoporosis
  • Chronic migraines
  • Alcoholism

On the other hand, some medications can interfere with the absorption or increase the losses of magnesium [2]:

  • Loop diuretics, including furosemide (Lasix®)
  • Proton pump inhibitors, including lansoprazole (Prevacid®)
  • Antibiotics, including ciprofloxacin (Cipro®)

Signs & symptoms of magnesium deficiency

Magnesium deficiency, or hypomagnesaemia is common in the general population, especially in older adults. Magnesium deficiency may be diagnosed if blood levels of magnesium are less than 0.75 mmol/L [9].

At the beginning, magnesium deficiency can present with little to no symptoms. As time goes on and the deficiency worsens, it’s important to look for the following signs and symptoms of magnesium deficiency [9]:

Early signs of magnesium deficiency

  • Fatigue and weakness
  • Loss of appetite
  • Nausea and vomiting
  • Body aches

Serious symptoms of magnesium deficiency

  • Muscle cramps and spasm
  • Poor memory
  • Arrhythmias

If magnesium deficiency progresses, it can manifest into more serious disorders, including seizures and heart problems. It’s important to speak with your doctor right away if you think you are deficient in magnesium or experience any of the above signs and symptoms.

Can I test for magnesium deficiency?

There are laboratory tests that exist to test for magnesium deficiency. A doctor will draw blood and measure the amount of magnesium found. The normal range for magnesium in blood is usually between 0.76-1.15 mmol/L [7].

However, estimations of magnesium status in the body can be difficult as up to 60% of magnesium is stored in the bones [7].This means that sometimes the amount of magnesium found in blood is not reflective of the overall amount in the body.

Because of the difficulties diagnosing magnesium deficiency, it’s important to speak with your doctor so they can perform an assessment based on your medical history, medications and signs and symptoms. You may also be referred to a dietitian who can assess your magnesium intake from food.

What foods should I be consuming each day to get enough magnesium?

The recommended daily intake for magnesium, from both foods and supplements, ranges from 270-300 mg

Some of the best sources of magnesium include:

  • Pumpkin Seeds (30g): 156 mg or 37% DV 
  • Almonds (30g): 80 mg or 19% DV
  • Spinach, boiled (125 ml): 78 mg or 19% DV
  • Black Beans, cooked (125 ml): 60 mg or 14% DV
  • Yogurt, plain (250 ml): 24 mg or 10% DV
  • Salmon, cooked (30g): 26 mg or 6% DV



  1. Maxfield, L., & Crane, J. S. (2019). Vitamin C deficiency (scurvy). StatPearls [Internet].
  2. National Institutes of Health. (2020, September 25). Magnesium. Dietary Supplement Factsheet.
  3. Public Health England. (2016, August 01). Government Dietary Recommendations. Government recommendations for energy and nutrients for males and females aged 1 – 18 years and 19+ years.
  4. Adams, J., & White, M. (2015). Characterisation of UK diets according to degree of food processing and associations with socio-demographics and obesity: cross-sectional analysis of UK National Diet and Nutrition Survey (2008–12). International Journal of Behavioral Nutrition and Physical Activity, 12(1), 1-11.
  5. Volpe, S. L. (2013). Magnesium in disease prevention and overall health. Advances in nutrition, 4(3), 378S-383S.
  6. Huang, Y. C., Wahlqvist, M. L., Kao, M. D., Wang, J. L., & Lee, M. S. (2015). Optimal dietary and plasma magnesium statuses depend on dietary quality for a reduction in the risk of all-cause mortality in older adults. Nutrients, 7(7), 5664-5683.
  7. Gröber, U., Schmidt, J., & Kisters, K. (2015). Magnesium in prevention and therapy. Nutrients, 7(9), 8199-8226.