Dear Doctors: I am told that magnesium is very important, and that it can help with sleep and also with anxiety. Is that true? I struggle with anxiety, and a lot of times it keeps me from falling asleep. I'm interested in trying a supplement but not sure how it works.
Dear Reader: You're absolutely right that magnesium is crucial to good health. It plays a role in more than 300 enzyme systems that regulate metabolic processes throughout the body. These include nerve and muscle function and controlling blood sugar and blood pressure. It also plays a role in protein and DNA synthesis and skeletal development. In fact, it would be easier to say what the mineral doesn't do in the body than to list what it does.
Magnesium is an essential nutrient. It's a chemical substance the body needs to function, but the body can't produce it on its own. That means we have to get magnesium through what we eat. However, estimates suggest that up to half of us don't get the recommended minimums for the mineral. Certain health issues can also increase the risk of magnesium deficiency. Digestive problems such as Crohn's or celiac disease can cause this. Other causes could be metabolic disorders such as poorly controlled diabetes, alcohol dependence or eating lots of ultra-processed foods.
It's true that magnesium can play a role in sleep and mood. That may be why the mineral is having a moment on social media. Unfortunately, there's limited and mixed evidence that taking a magnesium supplement can improve sleep or ease anxiety. A study published in 2017 suggested that magnesium supplements may ease symptoms of mild or moderate depression. Participants also described reduced anxiety. However, the sample size of the study was quite small, with just 112 adults. It also lacked a placebo as a control. Reviews of studies that focus on magnesium's effect on anxiety conclude that while the data suggests an easing of symptoms, the results are inconclusive. The idea that magnesium can ease insomnia has slightly better support.
What is clear is that getting enough magnesium in the diet is crucial to good health. Adult women need 310 to 320 mg per day. Adult men should aim for 400 to 420 mg per day. Good sources include spinach, Swiss chard, pumpkin seeds and almonds. Black beans, quinoa, avocados, green peas, milk, yogurt and dark chocolate are also good sources. Magnesium supplements are widely touted on social media, but approach them with care. Taking too much can cause side effects such as diarrhea, nausea and abdominal discomfort. Very high doses can cause low blood pressure, muscle weakness and irregular heartbeat.
The National Institutes of Health sets the upper limit for magnesium from supplements at 350 mg per day. This is in addition to dietary sources of magnesium. People with impaired kidney function should be especially careful about daily dosage. Anyone planning to take a supplement should seek guidance from a registered dietitian or their healthcare provider.
(Send your questions to [email protected], or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10960 Wilshire Blvd., Suite 1955, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)
