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United States Department of Agriculture

Agricultural Research Service

Do you have trouble sleeping? More magnesium might help
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By Forrest Nielsen 
 
Can't sleep? You are not alone. Not being able to sleep, or insomnia, is a common complaint, especially among people older than 50. More than half of all people aged 65 years and older have sleep problems.

Not surprisingly, lack of sleep is caused mainly by factors that are more common later in life, such as breathing problems, illness and medications. Yet, scientists have proved that poor sleep is not a natural part of aging.

Five common complaints are trouble falling asleep, waking up, awaking too early, needing to nap and not feeling rested.

Lack of sleep is a health concern because it can cause attention and memory problems, depressed mood and body chemistry changes that foster heart disease, diabetes and osteoporosis.

A factor getting more attention recently is poor nutrition. A low intake of the mineral magnesium may be one nutritional factor causing sleep problems.

Magnesium plays a key role in the body's chemistry that regulates sleep. This may be why persons with long-term lack of sleep, or abnormal brain waves during deep sleep, often have low magnesium in their blood.

Some small studies with humans and rats also suggest that magnesium is needed for good sleep. Magnesium treatment increased deep sleep and improved brain waves during sleep in 12 elderly subjects. Magnesium treatment decreased time to fall asleep and improved sleep quality of 11 alcoholic patients who often have a low magnesium status. Magnesium deficiency increased time awake at the expense of deep sleep in rats. Feeding magnesium to the rats restored their sleep patterns to normal.

The diets of many people do not contain enough magnesium for good health and sleep. In 1997, the United States Food and Nutrition Board set the recommended dietary allowance (or daily intake) for magnesium at 320 milligrams for women and 420 milligrams for men between ages 51 and 70. Last year, a much lower RDA of 237 milligrams per day was suggested for both men and women. This RDA was based on magnesium intake and body loss data from 27 human experiments with 243 subjects at the Grand Forks Human Nutrition Research Center.

Regardless of which RDA is correct, a national food consumption survey found that many Americans, especially older women, consume less than the RDA for magnesium. One analysis of the survey data found average daily magnesium intakes of 222 milligrams for white women, 176 milligrams for Spanish-American women and 150 milligrams for African-American women between the ages of 51 and 70 years.

Another risk factor for low magnesium status in older women is the use of calcium supplements without magnesium for bone health. High calcium intakes can make magnesium deficiency worse.

Perhaps, you have heard or read of the folk remedy of drinking a glass of warm milk before going to bed if you have trouble with falling asleep. This remedy may work for some people because milk is a fair source for magnesium. A glass of milk provides about 30 milligrams of magnesium. This amount of magnesium could be the difference between a deficient and adequate magnesium status for many people. Other foods that have good amounts of magnesium are whole grains, nuts and green leafy vegetables. Green leafy vegetables are a good source of magnesium because the green color is chlorophyll, a chemical that contains magnesium and converts sunlight into food energy.

We are planning to conduct an experiment in the Grand Forks Human Nutrition Research Center that will determine whether magnesium improves sleep behavior in people under normal life style conditions. The experiment also should identify factors that result in a relationship between magnesium and sleep. We will be looking for men and women 51 years or older with sleep problems willing to take a magnesium supplement or placebo (sugar) in pill form for seven weeks.

The study will require the filling out of questionnaires about diet, sleep, health, activity and mood. Three times during the study, subjects will have blood drawn and will have to wear an activity monitor for three 7-day periods.

If you would like to be part of the magnesium and sleep study, please call (701) 795-8396 for more information.

 


Last Modified: 7/9/2007
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