How can I tell if I have low magnesium?
In this article, we look at why people need magnesium, what magnesium deficiency means, and what the main symptoms of deficiency are. We also cover diagnosis, recommended dietary allowance (RDA), foods to eat, tips for improving absorption, and magnesium supplements.
Why do we need magnesium?
Nerve and muscle function depend on magnesium.
Magnesium is an essential mineral and electrolyte that plays a role in many bodily processes, including:
- energy production
- bone and teeth structure
- muscle function
- nerve function
- DNA replication
- RNA and protein synthesis
As such, it is vital that people are getting enough magnesium in their diet each day to stay healthy.
What does magnesium deficiency mean?
The National Health and Nutrition Examination Survey (NHANES) of 2005–2006 found that the majority of people in the United States were not getting enough magnesium in their diet.
However, the body can retain good levels of magnesium, so it is quite rare for a person to experience deficiency symptoms.
Certain factors can, however, increase a person's risk of developing magnesium deficiency symptoms. These include:
- continually eating a low-magnesium diet
- having gastrointestinal disorders such as Crohn's disease, celiac disease, or regional enteritis
- losing excessive amounts of magnesium through urine and sweat resulting from genetic disorders or drinking too much alcohol
- being pregnant and lactating
- being hospitalized
- having parathyroid disorders and hyperaldosteronism
- having type 2 diabetes
- being older
- taking certain medications, such as proton pump inhibitors, diuretics, bisphosphonates, and antibiotics
Long-term magnesium deficiency may have adverse effects on:
- bone density
- brain function
- nerve and muscle function
- digestive system
Loss of bone density can be of particular concern. In younger people, magnesium deficiency may prevent bone growth. It is vital to get enough magnesium during childhood when the bones are still developing.
A magnesium deficiency may cause loss of appetite and nausea.
Early signs of magnesium deficiency may include:
- loss of appetite
As deficiency progresses, people may experience:
- lower calcium levels in the blood, known as hypocalcemia
- lower potassium levels in the blood called hypokalemia
- numbness and tingling in the extremities
- cramps and muscle contractions
- personality changes
- abnormal heart rhythms
- coronary spasms
Prolonged magnesium deficiency can have an adverse impact on a person's long-term health and increase the risk of chronic diseases, including:
Anyone who experiences any of the above symptoms should see a doctor for tests to establish the cause.
Diagnosis and RDA
Diagnosis of magnesium deficiency varies between different countries. This is because it is difficult to accurately measure the amount of magnesium in a person's body. In the United States, doctors estimate a person's dietary intake to establish their magnesium status.
According to the National Institutes of Health, the RDA for people between the ages of 19 and 30 years old is:
- 310mg for females
- 400mg for males
For people aged 31 years or older, the RDA is:
- 320mg for females
- 420mg for females
Requirements are higher in teenagers aged between 14 and 18 years old, as well as for those who are pregnant. Younger children require less magnesium than teenagers and adults.
Foods to eat
It is possible to reach the RDA for magnesium by eating foods that contain high levels of magnesium, such as green vegetables, fruit, whole grains, cereals, and legumes.
Some foods high in magnesium, listed from highest to lowest magnesium content, include:
- nuts, especially almonds, cashews, peanuts
- black beans
- peanut butter
- whole wheat bread
- fortified cereals and other foods
Other foods containing magnesium include:
- kidney beans
- banana and apples
- fish, such as salmon and halibut
- chicken breast
- broccoli and carrot
When magnesium levels are low, the body absorbs extra magnesium from the small intestine, while reducing the amount that is excreted by the kidneys.
Tips for improving magnesium absorption
Eating raw vegetables may improve magnesium absorption.
Certain nutrients and conditions can affect how much magnesium a person absorbs. People wanting to increase their magnesium levels by improving absorption could try:
- reducing or avoiding calcium-rich foods two hours before or after eating magnesium-rich foods
- avoiding high-dose zinc supplements
- treating vitamin D deficiency
- eating raw vegetables instead of cooking them
- quitting smoking
A doctor may recommend magnesium supplements for people who have poor magnesium absorption or an underlying health condition that may prevent sufficient magnesium intake. Doctors might recommend that people over 60 years of age take a magnesium supplement, as absorption decreases with age.
Anyone considering taking a supplement should speak to a doctor first to ensure the supplement does not interfere with any medications they may be taking.
A doctor can also advise on whether a person needs to take a magnesium supplement. Some studies have suggested that taking vitamin and mineral supplements when unnecessary may have no effect or even be harmful.
Magnesium supplements are available in a variety of formulations, such as:
- magnesium oxide
- magnesium citrate
- magnesium chloride
A person's body absorbs the magnesium from the citrate and chloride formulations more efficiently than the oxide form.
Exceeding the recommended dose of magnesium can cause diarrhea, cramping, and nausea. Infants, older adults, and people with reduced renal function are at increased risk of magnesium toxicity and should avoid high-dose supplements.
Many people are not getting enough magnesium in their diet. However, for people without an underlying health condition, it is unusual to experience symptoms of magnesium deficiency.
Most people can increase their magnesium levels by eating more magnesium-rich foods. Anyone experiencing symptoms of deficiency should see a doctor.