Surprising Side Effects of Taking Magnesium Supplements, Say Dietitians — Eat This Not That

By Ghuman

Introduction

Magnesium is an essential mineral that plays a role in many bodily functions, including muscle and nerve function, blood sugar control, and energy production. While it’s found naturally in many foods, some people may need to supplement with magnesium to meet their daily needs. But taking too much magnesium can have some surprising side effects. Dietitians weigh in on what to look out for and how to get the right amount of magnesium in your diet.

Surprising Side Effects of Taking Magnesium Supplements, Say Dietitians

Magnesium is an essential mineral that plays a role in over 300 biochemical reactions in the body. It helps regulate blood pressure, blood sugar levels, and muscle and nerve function. It’s also important for bone health and energy production. While magnesium is found in many foods, some people may need to take a supplement to get enough of the mineral.

But taking too much magnesium can have some unexpected side effects. Here’s what dietitians want you to know about the potential risks of taking magnesium supplements.

1. Diarrhea

One of the most common side effects of taking too much magnesium is diarrhea. Magnesium is a natural laxative, so taking too much can cause loose stools or even watery stools. If you experience diarrhea after taking a magnesium supplement, reduce your dosage or stop taking the supplement.

2. Abdominal Cramping

Another common side effect of taking too much magnesium is abdominal cramping. Magnesium can cause the muscles in the intestines to relax, which can lead to cramping and discomfort. If you experience abdominal cramping after taking a magnesium supplement, reduce your dosage or stop taking the supplement.

3. Nausea

Nausea is another potential side effect of taking too much magnesium. Magnesium can irritate the stomach lining, which can lead to nausea and vomiting. If you experience nausea after taking a magnesium supplement, reduce your dosage or stop taking the supplement.

4. Low Blood Pressure

Taking too much magnesium can also cause low blood pressure. Magnesium helps regulate blood pressure, so taking too much can cause the blood pressure to drop too low. If you experience low blood pressure after taking a magnesium supplement, reduce your dosage or stop taking the supplement.

5. Muscle Weakness

Taking too much magnesium can also cause muscle weakness. Magnesium helps regulate muscle function, so taking too much can cause the muscles to become weak and tired. If you experience muscle weakness after taking a magnesium supplement, reduce your dosage or stop taking the supplement.

Conclusion

Magnesium is an essential mineral that plays a role in many biochemical reactions in the body. While taking a magnesium supplement can be beneficial, it’s important to be aware of the potential side effects. If you experience any of the side effects listed above, reduce your dosage or stop taking the supplement.

Since it can be tricky to stick to a perfectly balanced diet at all times, it’s not uncommon for people (particularly as they age) to take certain supplements in an effort to ensure their bodies are getting the nutrients they need. And while supplements can help rectify some concerning nutrient deficiencies, they can also lead to some problems of their own.

Magnesium is a particularly tricky nutrient because it is involved in a variety of bodily functions. It can also be dangerous if you have either too little or too much magnesium in your system, so finding that perfect balance is key.

“Magnesium is a rarely considered mineral that plays many roles in the body—over 600 functions at the cellular level. While it is a small nutrient, a deficiency has significant implications,” says Trista Best, RD, a registered dietitian at Balance One Supplements.

Keep reading for some surprising side effects caused by magnesium supplements, according to dietitians.

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As an electrolyte, magnesium interacts with sodium levels in the body, which can cause some dramatic results. For example, “magnesium supplementation can stimulate the osmotic activity of unabsorbed salt in the small intestine and colon and also increase gastric motility,” says Mary Wirtz, RD, a registered dietitian, and consultant for Mom Loves Best. Gastric motility is the movement of food from the mouth all the way through your intestines, thus supplementing with magnesium can speed up digestion to the point that you may experience loose bowel movements.

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“On top of a well-rounded diet, magnesium supplementation can offer many benefits. If you struggle with constipation, magnesium may improve bowel regularity along with ample hydration,” shares Skylar Griggs MS, RD, LDN, a registered dietitian and nutrition expert in the Boston area. “Specifically, magnesium citrate allows for the increase of water in the digestive tract and relaxation of the bowel muscles.”

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“Along with fighting depression and lowering blood pressure, magnesium is linked to better sleep in both quality and quantity,” Best explains. “It does this by regulating and activating parasympathetic hormones and neurotransmitters that help the brain to enter a state of relaxation which is better prepared for rest. Magnesium also helps to control the symptoms of some conditions that interrupt sleep, like digestive disorders.” She adds: “Magnesium deficiencies almost always lead to or exacerbate insomnia.”

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According to Wirtz, taking magnesium supplements can also cause magnesium toxicity, which in turn can “result in various side effects such as low blood pressure, vomiting, retention of urine, depression, and muscle weaknesses.”

However, Wirtz clarifies that this particular side effect is unusual and “generally associated with extreme amounts of supplementation and/or underlying impaired kidney function.”

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“Magnesium is a mineral that plays an essential role in maintaining proper blood pressure and keeping our bones strong,” Griggs explains. “Some of the richest sources of dietary magnesium include dark leafy greens, salmon, nuts, and seeds.”

Related: The #1 Best Diet to Lower Your Blood Pressure, Says Dietitian

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If you’re taking medications, especially antibiotics, Wirtz warns that you might want to steer clear of magnesium supplements, because they can interfere with the medicine. “It’s always important to discuss any specific nutrition supplements with your primary care provider,” she says.

Per a 2019 study, magnesium can have a negative impact on the absorption of some drugs, thus making them less effective. To err on the safe side, you can always supplement your diet through food sources of magnesium: 28 Best Foods to Eat for Magnesium.