Most adults in the United States don't consume enough magnesium, reports the U.S. Department of Agriculture. Your body needs magnesium to strengthen bones and teeth, to aid in energy metabolism, to regulate blood pressure and to help the nervous and muscular systems function appropriately. If you lack adequate magnesium, you may experience trouble sleeping, mental agitation, an abnormal heartbeat, fatigue, nausea, vomiting and frequent muscle cramps, including foot cramps. Talk to your doctor if you're concerned about your magnesium intake.
Who's at Risk
While most people don't get the magnesium they need, those who are severely deficient in the mineral are the most likely to develop muscle spasms and foot cramps. The elderly, Type 2 diabetics, chronic alcoholics and people with hyperthyroidism, pancreatitis and gastrointestinal disorders such as celiac disease, irritable bowel syndrome and Crohn's disease are at the greatest risk for magnesium deficiency. You may also have abnormally low magnesium levels if you regularly consume a high amount of soda, coffee or salt.
Some health experts recommend supplementing with magnesium to ward off deficiency and to prevent symptoms like foot cramps. However, a review study published in 2012 in the "Cochrane Database of Systematic Reviews" found that magnesium supplementation did not appear to be a reliable way of preventing muscle cramps in older adults or pregnant women. The researchers also concluded that there isn't enough evidence to determine if supplemental magnesium can effectively and safely treat cramps that are caused by disease or exercise.
Possible Side Effects
Do not attempt to self-treat foot cramps with supplemental magnesium until you've spoken to your doctor. Magnesium supplements may cause nausea, stomach pain and diarrhea. They may also interfere with the function of tetracycline antibiotics, diuretics, bisphosphonates used in the treatment of osteoporosis, digoxin, penicillamine and the tranquilizer chlorpromazine. Avoid supplemental magnesium if you have kidney or heart disease, and never consume more than the recommended dosage. Adults who take more than 350 milligrams of magnesium supplements daily may have an increased risk of heart and kidney problems and low blood pressure.
Dietary Sources of Magnesium
The best way to ensure you get the magnesium you need to avoid problems like foot cramps is to eat a diet that includes a variety of magnesium-rich foods. Good sources include bran breakfast cereals, brown rice, fish, nuts and vegetables like Swiss chard and spinach. A 1/2-cup serving of a ready-to-eat bran cereal contains approximately 112 milligrams of magnesium, or 28 percent of the recommended daily allowance for a 19- to 30-year-old man and 36 percent of the requirement for a woman of the same age.