Q. Does magnesium help you sleep?

A. Studies have found a link between low levels of magnesium, an essential mineral that plays a crucial role in a wide range of bodily processes, and sleep disorders. But if you are concerned you aren’t getting enough magnesium, changing your diet may be a better option than taking a supplement, as “there is really sparse evidence that taking super-therapeutic doses of magnesium will give you a benefit,” said Dr. Raj Dasgupta, a professor of pulmonary and sleep medicine at the University of Southern California.

The mineral is widely available in both plant and animal-based foods, and the kidneys limit urinary excretion of magnesium, so deficiencies are rare in healthy people. Leafy green vegetables, nuts, legumes and whole grains are good sources of magnesium; fish, chicken and beef also contain magnesium. Older adults and people with certain disorders, such as Type 2 diabetes, gastrointestinal diseases and alcoholism, however, may have inadequate amounts.

“Magnesium deficiency has been associated with higher levels of stress, anxiety and difficulty relaxing, which are key ingredients to getting good sleep at night,” Dr. Dasgupta said. He noted that magnesium interacts with an important neurotransmitter that favors sleep.

One small double-blinded clinical trial of 43 elderly people in Tehran who were randomly assigned to receive either 500 milligrams of magnesium or a placebo for eight weeks found that those who received the supplement fell asleep faster and spent more of their time in bed asleep, but their total sleep time was not necessarily longer.

An even smaller study of 10 people done nearly 20 years ago found that taking a magnesium supplement helped people with restless leg syndrome get more sleep.

If you suspect you’re deficient in magnesium or want to take magnesium supplements, talk to your doctor first. Magnesium can interact poorly with other drugs, and taking excessive amounts in the form of supplements can cause stomach cramps, diarrhea and nausea. Including more leafy green vegetables, legumes, nuts, seeds and whole grains in your diet may be a better option, doctors say.

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