Do you know what magnesium does for the human body, how much we need on a daily basis or what food sources provide it? Magnesium is an abundant mineral and its important to many biochemical processes including regulation of muscle and nerve function, blood glucose control, blood pressure regulation, protein formation and the structural development of bone.
The amount of magnesium we need depends on age and gender. For adults over age 51, the Recommended Dietary Allowance (RDA) is 320 mg/day for women and 420 mg/day for men. 50-60% of the magnesium in the body is found in the bones and most of the rest is present in soft tissue and blood serum. Magnesium balance is controlled by the kidney – when status is low, excretion in the urine is reduced; the body can conserve magnesium if reserves are low.
Magnesium is found naturally in many plant and animal products, as well as fortified foods like some breakfast cereals. It is also available as a dietary supplement and present in some medicines such as antacids and laxatives. The best way to meet the RDA is by choosing a variety of foods, and note that foods with dietary fiber generally contribute more magnesium. Consider these foods in your meal plan:
- Nuts (almonds, cashews & peanuts including “butters”), legumes (black beans
- and kidney beans), seeds (pumpkin and sunflower), whole grains (whole wheat
- bread & brown rice), and green leafy vegetables (spinach and Swiss chard)
- Fortified breakfast cereals and products fortified with 10% of the
- “Daily Value” for magnesium
- Soy products – soymilk and shelled edamame (green soybeans)
- Dairy products such as plain low fat yogurt and milk
Diets of most Americans provide less than the recommended amounts of magnesium. Men over age 70 and teenage girls are most likely to have low intakes. When magnesium from the diet and supplements are combined, intake is generally above recommended amounts. Deficiency, due to low dietary intake in healthy people, is not generally common due to the kidney’s ability to control excretion, but the following groups of people are more likely to get too little magnesium:
- Those with gastrointestinal diseases such as Crohn’s disease and celiac disease
- Those with type 2 diabetes and/or insulin resistance
- Those with long-term alcoholism
- Older adults whose intake of magnesium is less than younger adults; they are also more likely to be experiencing chronic diseases and taking medications affecting magnesium absorption
Several types of medications can interfere with magnesium status or function incorrectly if not taken at the right time with magnesium supplements. Those medications include biophosphates which are used to treat osteoporosis; antibiotics because absorption might be affected; diuretics which can increase or decrease magnesium loss depending on type of diuretic; and medications treating acid reflux or peptic ulcer which can affect blood levels of magnesium if taken for a long period of time. Check with your physician or pharmacist about all dietary supplements and medications you take, both prescription and “over the counter”, to avoid drug interference or interactions. Your healthcare provider is the best person to answer your specific health questions.
Information for this article was provided with assistance from “Magnesium” Fact Sheet for Consumers (reviewed 2/2014) and “Magnesium” Fact Sheet for Health Professionals (reviewed 11/2013) NIH Office of Dietary Supplements and National Nutrient Database for Standard Reference, Release 27, 2015.