Magnesium is considered a major mineral because the body needs it in higher quantities than trace minerals like iron or zinc. Magnesium serves as a co-factor in over 300 biochemical reactions in the body from synthesizing protein to controlling blood glucose, regulating blood pressure and building healthy bones. Magnesium is also required for energy production and transporting calcium and potassium across cell membranes, which helps with nerve transduction and muscle contraction, including the rhythm of the body’s hardest working muscle — the heart!
It is best to get nutrients, including magnesium, from foods since they provide other health benefits as well. In general, foods that have fiber provide magnesium, such as leafy greens, whole grains, beans, nuts, dairy products, and some fortified foods like cereals and pastas. Refining grains removes the nutrients from the bran and germ, which lowers the magnesium content. One serving of almonds (1 ounce) or spinach (1/2 cup) provides about 20 percent of the daily value of magnesium.
The typical American diet is low in fruits, vegetables and whole grains and high in refined grains. For this reason, surveys show that the average intake of magnesium is less than recommended. However, symptomatic magnesium deficiency is uncommon. If magnesium intake is low, the kidneys will limit urinary excretion of magnesium to help maintain homeostasis.
Very low intakes of magnesium over a long period of time or an excessive loss of magnesium due to a health condition such as celiac disease or type 2 diabetes or chronic alcoholism can lead to magnesium deficiency. Early signs include poor appetite, nausea, vomiting, fatigue and weakness. If the deficiency worsens, symptoms like numbness, tingling, muscle cramps, seizures, personality changes and abnormal heart rhythms can occur.
If you are concerned about magnesium deficiency, talk to your health care provider before starting a supplement. Magnesium supplements can interact with some medications. To avoid deficiency, focus on eating a balanced diet full of whole grains, fruits and vegetables.
Source: National Institutes of Health, https://ods.od.nih.gov/factsheets/Magnesium-HealthProfessional/