Is It Safe to Take Iron and Magnesium Together?
Whether taking iron with magnesium is safe will depend on whether we mean safe in general and, conversely, safe for your particular situation. If we mean safe in the latter sense, it will depend on factors such as which form of iron and magnesium supplements you are taking and your general health.
For example, evidence shows that ingesting iron supplements and magnesium peroxide leads to the formation of extra ‘oxygen free radicals’, a class of molecules that promote oxidative damage to the body [1]. So, it appears that combinations of iron and magnesium can be harmful, in the extreme, when magnesium peroxide is also present.
However, separate studies have demonstrated that magnesium won’t compete with oral iron absorption. One is a small-scale study examining the combination of ferrous gluconate (a form of iron) and magnesium-L-aspartate hydrochloride. When administered together by mouth, this formula did not prevent iron absorption [2].
In fact, in another study, supratherapeutic doses of iron (i.e., more significant than the recommended therapeutic dose) did not reduce iron absorption in humans after magnesium hydroxide [3].
Risks of Taking Iron and Magnesium Together
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An example of a risk is a rise in reactive oxygen species (ROS) formation. This increases oxidative stress, a risk factor for health problems in which oxidants attack cells and cause damage [5].
Concomitant iron and folic acid supplementation can further decrease magnesium status in the body, as observed in a study of young women [6].
Magnesium & Iron Side Effects
Potential side effects of taking iron and magnesium together include:
- upset stomach,
- diarrhoea,
- nausea,
- and abdominal cramping [7].
More severe symptoms can result from taking large amounts of these supplements, including muscle weakness, low blood pressure, drowsiness, irregular heartbeat, and, in severe cases, cardiac arrest [8].
However, note that these side effects can also occur from simply taking magnesium alone.
Interactions with Other Medications
When taken with certain medications, such as antibiotics, calcium channel blockers, muscle relaxants, water pills and bisphosphonates, magnesium is better tolerated if taken two hours apart from the pills. Iron can also interact with other medicines, so it’s always a good idea to consult a health provider before starting another supplement [4].
Considerations For Specific Populations
Populations at greater risk of experiencing adverse effects by taking iron and those with kidney disease for whom the kidneys might not be adept at removing excessive amounts of magnesium from the body [4]. Those who are pregnant might also wish to consult their doctor about taking magnesium supplements [9].
In summary, iron and magnesium are nutritionally essential, but their combined intakes reduce iron absorption, increase oxidative stress and may cause a range of side effects. Anyone considering adding supplements, especially iron and magnesium, to their diets should first consult a healthcare provider.