What Level of Magnesium Is Too Low?

Medically Reviewed on 9/22/2022
What level of magnesium is too low?
Magnesium is a mineral that is an essential electrolyte needed for several body functions.

The normal adult value for serum magnesium levels is:

  • 1.46 to 2.68 mg/dL
  • 1.5 to 2.5 mEq/L
  • 0.75 to 0.95 mmol/L

Magnesium deficiency (Hypomagnesemia) is an electrolyte disturbance caused when there is a low level of serum magnesium in the blood typically less than:

  • 1.46 mg/dL
  • 0.75 mmol/L

A value of magnesium levels below 1.25 mg/dL is considered severely low.

Normal daily requirements of magnesium

According to the National Institutes of Health, the recommended dietary allowance (RDA):

  • For people between 19 and 30 years:
    • Females: 310 mg
    • Males: 400 mg
  • For people above 31 years:
    • Females: 320 mg
    • Males: 420 mg

What is magnesium?

Magnesium is a mineral found in the body as well as in the earth’s crust.

It is an essential electrolyte needed for several body functions, such as bone health, cellular functions, nerve conduction, and other needs including:

What foods contain magnesium?

Magnesium is naturally found in many foods, such as:

  • Peanut butter
  • Nuts
  • Spinach
  • Beans
  • Whole grains
  • Bananas
  • Milk
  • Salmon
  • Magnesium-fortified breakfast cereals or bottled water

What are the symptoms of low magnesium (hypomagnesemia)?

Symptoms from low magnesium (hypomagnesemia) are not evident unless they persist for a long time. However, symptoms may include:

Magnesium deficiency also can cause hypocalcemia (decreased calcium levels) and hypokalemia (decreased potassium levels).

Magnesium affects the electrical activity of the myocardium and vascular tone making patients with hypomagnesemia at risk for cardiac arrhythmias.

QUESTION

According to the USDA, there is no difference between a “portion” and a “serving.” See Answer

What causes hypomagnesemia?

Hypomagnesemia can be attributed to:

How is hypomagnesemia diagnosed?

A blood test is the most common way to determine magnesium levels.

The doctor may also recommend checking the following in a patient suspected of having hypomagnesemia:

  • Serum phosphate and calcium levels
  • The basic metabolic panel, including serum creatinine/kidney function and glucose levels
  • Electrocardiogram

Complications of hypomagnesemia

Magnesium depletion can get complicated in many ways including neuromuscular, cardiovascular manifestations, and other electrolyte abnormalities.

  • Neuromuscular manifestations:
    • Tremors
    • Tetany (positive Trousseau and Chvostek signs, that means on tapping the side of the jaw or inner corner of the elbow, there is muscle twitch in the nearby areas)
    • Muscle spasms or muscle cramps
    • Seizures
    • Vertical nystagmus
    • Apathy
    • Delirium
    • Coma
  • Cardiovascular manifestations:
    • Electrocardiogram changes (widening of the QRS complex, peaked T waves, prolongation of the PR interval)
    • Atrial and ventricular premature systoles
    • Atrial fibrillation
    • Ventricular arrhythmias (torsades de pointes)
    • Cardiac ischemia
  • Other electrolyte and hormonal abnormalities:
    • Hypocalcemia
    • Hypoparathyroidism
    • Hypokalemia
  • Patients with hypomagnesemia should be encouraged to eat the following foods:
    • Green vegetables such as spinach
    • Beans
    • Legumes
    • Peas
    • Nuts
    • Seeds
    • Unrefined grains

For severe cases or those with significant hypomagnesemia, a doctor may recommend a high dose of magnesium supplements or injecting magnesium into a muscle or vein for some time.

Medically Reviewed on 9/22/2022
References
Image Source: iStock Image

Carol DerSarkissian. What Is a Magnesium Test? WebMD: https://www.webmd.com/a-to-z-guides/magnesium-test

Hypomagnesemia. NIH: https://www.ncbi.nlm.nih.gov/books/NBK500003/

Hypomagnesemia (Low Level of Magnesium in the Blood). MSD Manual: https://www.msdmanuals.com/en-in/home/hormonal-and-metabolic-disorders/electrolyte-balance/hypomagnesemia-low-level-of-magnesium-in-the-blood

Magnesium. Medscape: https://emedicine.medscape.com/article/2088140-overview#a1