Outright magnesium deficiency is considered rare. Chronic poor intake, combined with some medical conditions, could deplete magnesium stores. Elderly people may not absorb magnesium so well, and their kidneys may excrete it more readily. Alcoholism, kidney and digestive diseases can all contribute to poor absorption and excess loss in urine. Research has linked low blood magnesium levels to high blood pressure and heart disease.
What foods have magnesium? This mineral is a key part of the green pigment chlorophyll, which is abundant in green vegetables. So you can expect that leafy greens and other green-colored vegetables will be good sources of magnesium. It's also high in whole grains, nuts and nut butters. If you eat plenty of those foods every day, you likely have an adequate intake.
Unfortunately, diet surveys show that the average intake of this important mineral is below the RDA. For example, intake for adult men hovers around 320 mg/day, compared to the recommended intake of 420 mg. A diet full of highly processed foods, with few dark green vegetables or whole grains, would be low in magnesium.
Simply adding a supplement to an overly processed diet isn't a good solution, since those foods are also good sources of other key nutrients like potassium, antioxidants and fiber. Improving your intake from foods is the first step. Supplements, which typically provide 250 mg of magnesium, should be taken with food.
- Children 1-3 years old 80 mg/day
- Children 4-8 years old 130 mg/day
- Children 9-13 years old 240 mg/day
- Teens 14-18 years old 410 mg/day for boys, 360 mg/day for girls
- Adults 19-30 years old 400 mg/day for men, 310 mg/day for women
- Adults 31+ years old 420 mg/day for men, 320 mg/day for women
- Pregnant women 360 - 400 mg/day, depending on age
- Breastfeeding women 310 - 360 mg/day, depending on age