Magnesium in diet

Alternative names 
Diet - magnesium

Magnesium is an essential mineral for human nutrition.

Magnesium in the body serves several important metabolic functions. It plays a role in the production and transport of energy. It is also important for the contraction and relaxation of muscles. Magnesium is involved in the synthesis of protein, and it assists in the functioning of certain enzymes in the body.

Food Sources

Most dietary magnesium comes from vegetables, particularly dark green, leafy vegetables. Other foods that are good sources of magnesium are:

  • Soy products, such as soy flour and tofu  
  • Legumes and seeds  
  • Nuts (such as almonds and cashews)  
  • Whole grains (such as brown rice and millet)  
  • Fruits or vegetables (such as bananas, dried apricots, and avocados)

Side Effects

Toxic symptoms from increased magnesium intake are not common because the body eliminates excess amounts. Magnesium excess almost always occurs only when magnesium is supplemented as a medication.

Magnesium deficiency is rare. The symptoms include muscle weakness, fatigue, hyperexcitability, and sleepiness. Deficiency of magnesium can occur in alcoholics or people whose magnesium absorption is decreased due to surgery, burns, or problems with malabsorption (inadequate absorption of nutrients from the intestinal tract). Certain medications or low blood levels of calcium may be associated with magnesium deficiency.

Deficiency symptoms have three categories:

  • Early symptoms include irritability, anorexia, fatigue, insomnia, and muscle twitching. Other symptoms include poor memory, apathy, confusion, and reduced ability to learn.  
  • Moderate deficiency symptoms consist of rapid heartbeat and other cardiovascular changes.  
  • Severe deficiency of magnesium could lead to tingling, numbness, sustained contraction of the muscles, and hallucinations and delirium.


These are the recommended daily requirements of magnesium:

  • Children       o 1-3 years old: 80 milligrams       o 4-8 years old: 130 milligrams       o 9-13 years old: 240 milligrams       o 14-18 years old (boys): 410 milligrams       o 14-18 years old (girls): 360 milligrams  
  • Adult females: 310 milligrams  
  • Pregnancy: 360-400 milligrams  
  • Breastfeeding women: 320-360 milligrams  
  • Adult males: 400 milligrams


Johns Hopkins patient information

Last revised: December 8, 2012
by Brenda A. Kuper, M.D.

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