What Is Magnesium?
Magnesium is a mineral that's crucial to the body's function. Magnesium helps keep blood pressure normal, bones strong, and the heart rhythm steady.
Experts say that many people in the U.S. aren't eating enough foods with magnesium. Adults who get less than the recommended amount of magnesium are more likely to have elevated inflammation markers. Inflammation, in turn, has been associated with major health conditions such as heart disease, diabetes, and certain cancers. Also, low magnesium appears to be a risk factor for osteoporosis.
There's some evidence that eating foods high in magnesium and other minerals can help prevent high blood pressure in people with prehypertension.
Intravenous or injected magnesium is used to treat other conditions, such as eclampsia during pregnancy and severe asthma attacks. Magnesium is also the main ingredient in many antacids and laxatives.
Serious magnesium deficiencies are rare. They're more likely in people who:
- Have kidney disease
- Have Crohn's disease or other conditions that affect digestion
- Have parathyroid problems
- Take certain drugs for diabetes and cancer
- Are older adults
- Abuse alcohol
Health care providers sometimes suggest that people with these conditions take magnesium supplements.
Proton pump inhibitors (PPIs), a common type of medicine used to treat acid reflux, have also been tied to low magnesium levels. Examples of PPIs include dexlansoprazole (Dexilant), esomeprazole (Nexium), lansoprazole (Prevacid), omeprazole (Prilosec, Zegerid), pantoprazole (Protonix), and rabeprazole (Aciphex). If you take any of these medicines on a long-term basis, your health care provider may check your magnesium level with a blood test.
Magnesium Recommended Daily Allowance
The recommended dietary allowance (RDA) includes the magnesium you get from both the food you eat and any supplements you take.
Recommended Dietary Allowance (RDA)
31 years and over
Under 19 years: 400 mg/day
Under 19 years: 360 mg/day
31 years and up
Most people get more than enough magnesium from foods and do not need to take magnesium supplements. Excessive use of magnesium supplements can be toxic. In addition to what you get from food, the highest dose you should take of magnesium supplements is:
- 65 mg/day for children ages 1-3
- 110 mg/day for children ages 4-8
- 350 mg/day for adults and children ages 9 and up
These doses are the highest anyone should add to their diet. Many people ingest significant quantities of magnesium through the foods they eat. It's safe to get high levels of magnesium naturally from food, but adding large amounts of supplements to your diet can prove dangerous. Do not exceed these maximum advised levels.
Natural Sources of Magnesium
Natural food sources of magnesium include:
- Green, leafy vegetables, like spinach
- Beans, peas, and soybeans
- Whole-grain cereals
Eating whole foods is always best. Magnesium can be lost during refinement and processing.
- Side effects. Magnesium supplements can cause nausea, cramps, and diarrhea. Magnesium supplements often cause softening of stool.
- Interactions. Magnesium supplements may interact with certain medicines, including diuretics, heart medicines, or antibiotics. Check with your health care provider if you are taking any medicine before taking magnesium.
- Risks. People with diabetes, intestinal disease, heart disease or kidney disease should not take magnesium before speaking with their health care provider.
- Overdose. Signs of a magnesium overdose can include nausea, diarrhea, low blood pressure, muscle weakness, and fatigue. At very high doses, magnesium can be fatal.