What Happens When You Take Iron and Magnesium Together?

If you’re not getting enough nutrients from your diet, your doctor may recommend taking iron and magnesium supplements. The two mineral supplements can be taken together. However, they must be taken at different times and may cause unwanted side effects.

Iron is a mineral necessary for overall growth, energy, and many other bodily processes. It is needed to make hemoglobin, a protein found in red blood cells that carries oxygen from your lungs to the rest of your body.

Low iron levels can cause anemia (a low number of healthy red blood cells). Iron can be obtained through your diet by eating lean meat and seafood. It can also be taken as a supplement, alone or in combination with other vitamins and minerals.

Magnesium is a mineral that plays an important role in almost every bodily process. Examples include bone formation, muscle and nerve function, and blood pressure regulation.

It can be obtained through your diet from foods such as green leafy vegetables, nuts and seeds. Magnesium supplements are available in various forms, such as magnesium oxide and magnesium citrate.

Both iron and magnesium are useful for supporting your energy and that used by your cells:

• Iron supports oxygen transport throughout the body, which is essential for normal energy metabolism.
• Magnesium supports hundreds of cellular processes, giving your cells energy.
• Everything you do, from using your brain to moving your muscles, requires iron and magnesium in one way or another.

Iron absorption is reduced when taken with certain interfering minerals, including magnesium. To reduce the risk of potential absorption problems and less effective doses, separate the times you take your iron and magnesium supplements. It is often recommended to take them at different times of the day.

Clinicians recommend spacing iron and magnesium doses a few hours apart. At a minimum, take iron at least 1 hour before or at least 2 hours after taking magnesium (or eat a meal) to maximize absorption.

Magnesium, especially in high doses or in certain salts like magnesium oxide, can reduce iron absorption when taken at the same time. It does this by increasing intestinal pH and reducing iron solubility. In rare cases, extreme overconsumption of magnesium has been associated with iron deficiency anemia. Most typical supplement doses do not cause a significant effect.

Magnesium absorption varies depending on the type of magnesium supplement you take. Forms that dissolve easily in water are better absorbed from the gastrointestinal (GI) tract. Magnesium aspartate, citrate, glycinate, lactate and chloride are better absorbed by the body than magnesium oxide or sulfate.

Taking iron and magnesium may increase the risk of gastrointestinal side effects.

Possible side effects related to iron supplements include:

• Gastrointestinal side effects: Nausea, vomiting, constipation, diarrhea, flatulence (gas), and change of stools (poop) to a green or black color.
• Non-gastrointestinal side effects: Metallic taste, discoloration of teeth.

High doses of iron (45 milligrams per day or more) are more likely to cause gastrointestinal side effects.

It is generally recommended to take the iron on an empty stomach. However, if you notice gastrointestinal side effects, you can take the supplements with a small amount of food to reduce your risk. Try to avoid taking iron with milk, high-fiber foods, or caffeine. These can also affect how your body absorbs iron.

Magnesium generally doesn’t cause many serious side effects. However, taking higher doses may cause diarrhea, nausea, vomiting, and stomach cramps. These side effects are more commonly seen with certain forms of magnesium, such as magnesium carbonate, magnesium chloride, magnesium gluconate, and magnesium oxide.

If you want to take iron and magnesium together, talk to a healthcare professional. Various forms of supplements provide magnesium and iron, such as a multivitamin and mineral supplement. Depending on why you are taking the supplements, one form may be better than another. A healthcare professional can help you decide which option is best.

Magnesium and iron may also interact with other medications or supplements you take. Speak with a healthcare professional before starting either supplement. They can help you make sure it is appropriate and useful for you.