Magnesium is an essential mineral that many Americans don’t get enough of in their diet. Magnesium plays essential roles in health, such as regulating blood sugar and muscle function, and falling short on magnesium could lead to health issues like high blood pressure, poor sleep, and mood disorders.
Many people rely on magnesium supplements to both increase their magnesium intake and to improve issues like stress, headaches, and sleep issues.
But while magnesium supplements can be helpful, they don’t always work well with everything else in your supplement routine. Some nutrients compete with magnesium for absorption in the gut, which can negatively impact magnesium status.
Calcium supplements are commonly taken to improve and maintain bone health, often alongside magnesium.
Although it’s safe to take them together, separating magnesium and calcium supplements may improve the absorption and maximize the benefits of both of these nutrients.
Calcium and magnesium compete for absorption in the gut. Excess calcium blocks the absorption of magnesium into the cells lining the gut and increases urinary excretion of magnesium.
“When calcium is present in higher concentrations compared to magnesium, the body’s ability to absorb and use magnesium significantly decreases and supplementation is less effective,” Leigh Erin Connealy, integrative and functional medicine doctor and Medical Director at Center for New Medicine, told Health.
To get the most out of your magnesium and calcium supplements, Connealy recommends waiting around two hours between taking magnesium and supplementing with other minerals, like calcium.
Iron is a mineral that’s necessary for growth, energy production, hormone synthesis, and neurological development. It’s an essential part of hemoglobin, a protein in red blood cells that carries oxygen from the lungs to the rest of your body.
Like calcium, it’s generally safe to take iron and magnesium together. However, taking either in high doses can decrease the absorption of both minerals, as they compete for absorption in the gut.
While taking iron and small doses of magnesium usually won’t cause an issue, it’s best to take them separately, separated by a few hours, to promote optimal absorption.
Magnesium salts like magnesium oxide are more likely to reduce iron absorption. They may interfere with iron by raising the pH in the intestines. Since iron availability depends on an acidic environment, this reduces its absorption. Additionally, some forms of magnesium salts can directly bind to iron, further interfering with its absorption.
For the most benefits, it’s recommended to take iron separately from other minerals, like magnesium, ideally on an empty stomach.
Zinc is required for immune function, protein production, skin health, and many other essential processes. When taken in high doses, zinc and magnesium can compete for absorption.
“Zinc and magnesium are like two people trying to get through the same small doorway at the same time,” Jobby John, PharmD, the CEO and founder of both Lake Hills Pharmacy and also Nimbus Healthcare, told Health.
“They compete for the same absorption pathways in your small intestine. If you take a very large dose of zinc with magnesium, the zinc can “win” this competition, leading to less magnesium being absorbed,” he explained.
Doses of over 50 milligrams per day, which far exceeds the 40 milligram upper limit set for zinc, may interfere with magnesium absorption.
Other factors can influence how well your body absorbs and retains magnesium.
Here are other things that can affect magnesium absorption:
- Medications: Proton pump inhibitors (PPIs), diuretics, and antibiotics can reduce magnesium absorption or increase the amount of magnesium you lose through urine.
- Health conditions: “Conditions that affect the small intestine, such as Crohn’s disease, celiac disease, or diarrhea, can significantly impair the body’s ability to absorb magnesium and other nutrients,” John said.
- Nutrient levels: John explained that having adequate vitamin D levels is important for optimizing how much magnesium your body can use from food and supplements.
- Age: As you age, a natural decrease in stomach acid in the digestive tract can lead to reduced absorption of minerals, including magnesium.
- Diet: Excessive alcohol and caffeine consumption can interfere with magnesium absorption and also increases its excretion through the urine.
Being aware of how these factors influence your ability to absorb magnesium and maintain healthy levels can help you make smarter choices about your diet and supplement routine.
While magnesium supplements can help you reach and maintain optimal levels, taking magnesium supplements with mineral products, like calcium, iron, or zinc, may lead to reduced absorption or increased excretion.
To reduce this risk, it’s best to take magnesium separately from other minerals and to be aware of other factors, such as medications and medical issues, that could impact magnesium levels.
