Magnesium Requirements and Dietary Sources

Magnesium is a major mineral, and it's the fourth most abundant mineral; the adult body contains about 25 grams of magnesium. About 50% to 60% of the magnesium in your body is stored in your bones, while the rest is at work in the cells of your organs and other tissues.

Magnesium is required for more than 300 enzyme systems that carry out various biochemical reactions in the body. It's crucial for normal muscle and nerve function and helps maintain a regular heartbeat. You also need magnesium for strong bones and a healthy immune system.

Dietary Reference Intakes

The National Academies of Sciences, Engineering, and Medicine, Health and Medicine Division has determined the dietary reference intakes (DRI) for magnesium. The suggested daily intake varies by age and by sex. In addition, women who are pregnant need more magnesium. The Daily Value (DV), which is set by the Food and Drug Administration (FDA) and is found on food labels, recommends 420 milligrams of magnesium per day for children ages 4 and older.

Sources of Magnesium

Magnesium-rich foods include:

• Spinach
• Legumes, such as kidney beans, black beans, and edamame
• Nuts, including almonds, Brazil nuts, and cashews
• Seeds, such as pumpkin and chia seeds
• Potatoes with skin
• Whole grains and fortified cereals
• Yogurt
• Milk

Deficiency Symptoms

Magnesium deficiency is rare in healthy people, because the kidney prevents its excretion. But it can occur when you habitually don't consume enough foods that contain magnesium. It can also happen if you suffer from certain health problems or take medications that may result in the loss of magnesium or reduce the amount your body can absorb in your small intestine. Diabetes, alcoholism, Crohn's disease, celiac disease, or intestinal surgery may result in magnesium deficiency.

Older people are also at risk for magnesium deficiency due to overall decreased intake. Not getting enough magnesium may increase the risk of cardiovascular diseases, type 2 diabetes, and migraine headaches. In addition, magnesium deficiency decreases immune system function.

Symptoms of magnesium deficiency are weakness, fatigue, loss of appetite, nausea and vomiting. Numbness, tingling, muscle cramps, seizures, and abnormal heart rhythms can develop as the deficiency progresses. Severe deficiency can cause low calcium and potassium in the blood because homeostasis is disrupted.

If you have these symptoms or are at risk because of a medical condition, see a health care provider and registered dietitian nutritionist. They can order blood tests to determine if a magnesium deficiency is a problem or if there are other causes.

Magnesium Supplements

Magnesium supplements may be beneficial for people who take certain medications that may cause loss of magnesium or reduce absorption, such as diuretics and antibiotics. The elderly, alcoholics, and people with gastrointestinal absorption issues may all benefit from taking supplements.

Supplementation should not exceed 350 mg per day, Since supplements are not regulated by the FDA, make sure the bottle shows third-party verification of the contents (USP, NSF, or Consumer Labs, for example) before taking a supplement. Follow up with your health care provider and registered dietitian nutritionist.

Taking Too Much Magnesium

Getting too much magnesium from the foods you eat is very unlikely, because the kidneys excrete excessive intakes. But taking large amounts of dietary magnesium supplements can cause diarrhea, nausea, and abdominal cramps. Taking too much magnesium for longer periods of time may result in changes in mental status, nausea, loss of appetite, diarrhea, weakness, low blood pressure, difficulty breathing and irregular heartbeat.