All essential nutrients are important for health. Magnesium, not to be confused with manganese, is an essential mineral that gets too little appreciation.
This is surprising because most Americans do not consume adequate magnesium and the potential health consequences are extensive.
QUESTION: What are possible signs of chronic inadequate levels of magnesium?
ANSWER: Magnesium is critical in both muscle relaxation and for normal functioning of the nervous system.
Low magnesium can cause irritability that triggers muscle spasms and cramping, especially in the hands and feet.
Additionally, because chronic low magnesium intake leads to increased inflammation, it may be a factor in increasing the risk of asthma, headaches and developing medical conditions including diabetes, cardiovascular problems, seizures, stroke, chronic obstructive pulmonary disease and some types of kidney disease.
Also associated with lower magnesium levels are nervous-system problems related to anxiety, confusion, disorientation and even vertigo.
Q: How do you know if you are getting enough magnesium?
A: Magnesium status is not commonly evaluated in medical settings, partly because blood levels are not a good indication of dietary magnesium.
Like calcium, when the diet is low in magnesium, then magnesium can be mobilized from bone reserves to maintain blood levels. Calculating the amount of magnesium in the diet is a common way to evaluate magnesium status.
The amount of magnesium a person needs is dependent on body size — between 300 and 450 mg of magnesium per day.
Q: What are good food sources of magnesium?
A: Cooked spinach provides about 150 mg of easily absorbed magnesium per cup. Whereas, calcium and iron are poorly absorbed from spinach.
An ounce of most nuts and seeds contributes 50 to 75 mg of magnesium, and cooked beans have 70 to 100 mg per cup. Cooked brown rice has about 80 mg per cup compared to only 25 mg in white rice.
Milk products can be a significant source of magnesium with about 45 mg in a cup of yogurt and 25 mg in a cup of milk.
Q: What other factors affect magnesium needs?
A: Over restricting dietary salt increases magnesium loss in the urine.
Additionally, consuming excessive aluminum (especially those foods containing baking powder), alcohol, caffeine, phosphorus, vitamin D and calcium supplements (without magnesium added) can compromise magnesium status in the body.
Also, low intakes of vitamin D, vitamin B6 and selenium can impair magnesium status.
Magnesium from a supplement can cause diarrhea when taken in a dosage greater than 350 mg a day.
Choosing a diet with a wide variety of nuts, seeds, beans, whole grains and dairy can help to meet magnesium needs.
Alan Titchenal, Ph.D., C.N.S., and Joannie Dobbs, Ph.D., C.N.S., are nutritionists in the Department of Human Nutrition, Food and Animal Sciences, College of Tropical Agriculture and Human Resources, University of Hawaii at Manoa. Dobbs also works with University Health Services.
