Magnesium and iron are two essential minerals used for a variety of processes in the body. Even though you should speak to your doctor about taking magnesium and iron supplements at the same time, there is no evidence that the two supplements negatively interact.
Magnesium and iron supplements are typically fine to take together, but check with your doctor.
Recommended Magnesium Intake
According to the Linus Pauling Institute at Oregon State University, magnesium is necessary for energy production, protein synthesis, creating nucleic acid and transporting ions. It also regulates blood glucose control, blood pressure, muscle function and nerve function.
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The recommended daily allowances (RDAs) for magnesium are:
- 30 milligrams per day for infants ages 0 to 6 months
- 75 milligrams per day for babies ages 7 to 12 months
- 80 milligrams per day for toddlers ages 1 to 3
- 130 milligrams per day for children ages 4 to 8
- 240 milligrams per day for children ages 9 to 13
- 410 milligrams per day for teenage boys ages 14 to 18
- 360 milligrams per day for teenage girls ages 14 to 18
- 400 milligrams per day for men ages 19 to 30
- 310 milligrams per day for women ages 19 to 30
- 420 milligrams per day for men ages 31 to 50 and men ages 51 and over
- 320 milligrams per day for women ages 31 to 50 and women ages 51 and over
- Between 350 and 400 milligrams per day for pregnant people
- Between 310 and 360 milligrams per day for breastfeeding people
Good dietary sources of magnesium include leafy greens, nuts, legumes and whole grains. Some breakfast cereals are also fortified with magnesium.
Recommended Iron Intake
Iron is crucial for creating hemoglobin, a substance in your red blood cells that helps transport oxygen to your organs and tissues. Iron is also used to create some hormones and is needed for growth and cell function. There are two types of dietary iron. Heme iron, found in animal products, is absorbed more easily by the body than nonheme iron based in plant products. Three ounces of cooked chicken liver provides almost 10 milligrams of iron; a 3-ounce serving of raw Pacific oysters provides over 5 milligrams of iron; and 1 cup of fortified puffed-wheat cereal provides almost 4 milligrams of iron.
How much iron you need every day depends on your age and sex. According to the National Institutes of Health Office of Dietary Supplements, the recommended daily allowances (RDAs) for iron are:
- 11 milligrams per day for babies ages 7 to 12 months
- 7 milligrams per day for toddlers ages 1 to 3
- 10 milligrams per day for children ages 4 to 8
- 8 milligrams per day for children ages 9 to 13
- 11 milligrams per day for men ages 14 to 18
- 15 milligrams per day for women ages 14 to 18
- 8 milligrams per day for men ages 19 to 50
- 18 milligrams per day for women ages 19 to 50
- 27 milligrams per day for pregnant people
- 9 to 10 milligrams per day for breastfeeding people
- 8 milligrams per day for adults over 51 years of age
Low Magnesium Levels
Magnesium deficiency is quite rare. According to Harvard Health Publishing, your kidneys can regulate the amount of magnesium lost through urination. However, some factors that can affect mineral and vitamin absorption and contribute to low magnesium levels in the body include:
- Gastrointestinal disorders like celiac disease and Crohn's disease
- Renal disorders such as diabetes mellitus and long-term diuretic use
- Endocrine and metabolic disorders like diabetes mellitus or parathyroid gland disorders
Symptoms of low magnesium include abnormal eye movements, muscle spasms, muscle cramps, fatigue, muscle weakness, numbness and convulsions. Your doctor can do a blood test to check your magnesium levels and recommend what steps to take if your magnesium levels are low. Treatments for magnesium deficiency include taking oral magnesium supplements or receiving intravenous magnesium.
Iron Deficiency and Anemia
If you don't have enough iron in your body, you may be diagnosed with a condition called iron-deficiency anemia (there are other types of anemia caused by low vitamin absorption). Symptoms include fatigue, having a swollen or irritated tongue, an increased heart rate, feeling dizzy when you stand up, pale or sallow skin and a craving to eat nonfood items like ice or dirt.
Your doctor can use a blood test to assess your iron levels and see if you meet the criteria for anemia. Treatments for iron-deficiency anemia include adding iron-rich foods to your diet, taking iron supplements or receiving intravenous iron.
Do Magnesium and Iron Interact?
According to the Linus Pauling Institute, magnesium and iron each interact with a few other nutrients. However, they do not seem to affect each other. Possible interactions include:
- High doses of zinc — decreased magnesium absorption
- A large increase in dietary fiber intake — decreased magnesium absorption
- Vitamin D — increased magnesium absorption
- A Vitamin A deficiency — possible worsening of iron-deficiency anemia through alteration of iron metabolism
- Calcium — decreased absorption of both heme and nonheme iron
- Zinc deficiency — possible worsening of iron-deficiency anemia
- Low copper levels — decreased iron absorption
- Low iron — possible effect on iodine levels
If you have any chronic health conditions, ask your physician if those can affect mineral and vitamin absorption. Magnesium and iron may also interact with medications you're taking:
- Magnesium interacts with a heart medication called digoxin, an antibiotic called nitrofurantoin and some anti-malarial drugs
- Iron interacts with antacids, some antibiotics and levothyroxine thyroid medication
- Oregon State University: Linus Pauling Institute: "Magnesium"
- National Institutes of Health: Office of Dietary Supplements: "Magnesium"
- USDA National Nutrient Database: "Chard, Swiss, Cooked, Boiled, Drained, Without Salt"
- USDA National Nutrient Database: "Spinach, Cooked, Boiled, Drained, Without Salt"
- USDA National Nutrient Database: "Lima Beans, Immature Seeds, Cooked, Boiled, Drained, With Salt"
- USDA National Nutrient Database: "Fish, Salmon, Chinook, Cooked, Dry Heat"
- National Institutes of Health Office of Dietary Supplements: "Iron"
- USDA National Nutrient Database: "Chicken, Liver, All Classes, Cooked, Simmered"
- USDA National Nutrient Database: "Mollusks, Oyster, Pacific, Raw"
- USDA National Nutrient Database: "Cereals Ready-to-Eat, Wheat, Puffed, Fortified"
- Merck Manual: "Hypomagnesemia"
- Harvard Health Publishing: "What You Should Know About Magnesium"
- MedlinePlus: "Low Magnesium Level"