Magnesium Supplements: Benefits, Side Effects and Intake

Magnesium is a mineral that is vital for the body to work properly. Because the body cannot make magnesium, it needs to be taken in through the diet.

To get enough of this essential nutrient, men and women are recommended to take in 400-420 mg and 320-360 mg a day respectively, depending on age.

What Is Magnesium?

Magnesium is the fourth most abundant mineral in the body. It is needed for hundreds of metabolic processes, from nutrient and energy production to building important proteins such as those involved in DNA synthesis, and for many other important body functions.

Dietary sources of magnesium include pulses, nuts, seeds and green leafy vegetables. It is found in smaller amounts in meat and fish.

However, despite its importance, research shows that almost 50% of people in Western countries in Europe and the United States do not get enough of this essential mineral.

Effects of Magnesium on Health

It is important to get enough magnesium to help the body work at its best. Although it is possible to get enough of this mineral through diet, if you find it hard to meet your needs from food, a supplement may help, but please speak to your doctor first. Research has looked at magnesium in relation to heart health, blood pressure, mood and blood sugar control.

Blood Pressure

Magnesium supplements have been studied for their possible effect on blood pressure levels. Research has observed that in people with high blood pressure, supplementing this mineral was associated with lower blood pressure. A review of 22 studies showed that an average of 410 mg of magnesium supplements a day was associated with a 3-4 mmHg fall in systolic blood pressure (the higher number) and a 2-3 mmHg fall in diastolic blood pressure.

Similarly, a recent review of 34 studies concluded that taking about 350 mg of magnesium a day for an average of 3 months was associated with a reduction of 2.00 mmHg in systolic and 1.78 mmHg in diastolic blood pressure. Blood pressure should be managed with your doctor and not with supplements alone.

The Effect of Magnesium on Mood

Some research links low magnesium levels with depression. In studies of older adults with type 2 diabetes, magnesium deficiency and depression, magnesium has been looked at in relation to depressive symptoms.

In another 6-week study of 126 people with mild to moderate depression, those who took the mineral alongside their usual treatment reported an improvement in depression scores. However, these studies were not blinded, which means participants knew they were taking the mineral, which could skew the results. In the end, larger and longer studies are needed in this area. Magnesium is not a treatment for depression, and you should speak to your doctor about low mood.

Migraine

Low magnesium levels have been linked with migraine, a condition characterised by intense, recurring headaches. Some studies have looked at magnesium supplements in people with migraine, and more research is needed before any recommendations can be made. Please speak to your doctor about migraine.

Muscle Relaxation

Magnesium acts as a natural calcium blocker and helps muscle cells relax after they contract. When magnesium levels are low, muscles can contract more and may cause symptoms such as cramps and muscle spasms.

Sleep Quality

In a study of 46 older adults, those who took a daily magnesium supplement were seen to fall asleep faster. Sleep quality was also seen to improve and symptoms of sleeplessness to lessen.

In addition, animal studies have seen that magnesium regulates the production of melatonin, a hormone that guides the body's sleep-wake cycle.

Magnesium has also been seen to bind to gamma-aminobutyric acid (GABA) receptors. The GABA hormone helps calm nerve activity that can affect sleep.

Magnesium Side Effects and Risks

Although magnesium supplements are generally considered safe, you should speak to a health professional before taking them, especially if you have a medical condition.

Mineral supplements may not be safe for people taking certain diuretics, heart medications or antibiotics. Most people who take magnesium supplements do not experience side effects, but they can cause bowel-related problems such as diarrhoea, nausea and vomiting, especially at high doses.

It is important to note that people with kidney problems are at a higher risk of adverse effects from these supplements. In addition, there is not enough evidence that magnesium supplements benefit people who are not deficient in magnesium.

How Much Magnesium Is Taken?

Depending on the brand, magnesium supplements on the market typically provide 200-400 mg per day.

This means that a supplement may provide you with the full reference daily intake (RDI) or more. The Food and Nutrition Board of the US Institute of Medicine has set a tolerable upper limit of 350 mg a day for supplemental magnesium. Below this, you are unlikely to experience any digestive side effects.

If you have a severe magnesium deficiency, you may need a higher amount, but you should consult a health professional before taking magnesium in high doses that exceed the RDI. The amount that is right for you should be agreed with your doctor.

Which Type of Magnesium Should Be Chosen?

Some magnesium supplements come in various forms that your body may absorb better than others. The better-absorbed forms of this mineral include:

However, other factors such as your genes and whether you have a severe deficiency can also affect absorption.

In addition, although many studies show that certain types of magnesium supplements are more absorbable than others, some studies find no difference between the various formulations.

This article is for general information only; please consult your doctor and dietitian about your own situation.