Doctors Reveal Which Builds Stronger Bones

There are a variety of vitamins and minerals that help keep your bones strong and healthy. Two of the most important are calcium and magnesium, each of which plays a different role in bone health. But if it’s calcium vs. magnesium for bone health, does one mineral deserve more of your attention than the other?

Meet the experts: Gbolahan Okubadejo, M.D., a spine surgeon and head of The Institute for Comprehensive Spine Care in the New York City area; Brynna Connor, M.D., a family medicine physician in Austin and a healthcare ambassador at NorthwestPharmacy.com.

Here, doctors explain the ways that calcium and magnesium both directly and indirectly support better bone health, along with what to know if you’re supplementing with either and which is more important for building strong bones.

If you want your bones to be dense and strong, you need calcium. “Calcium is the main ion that provides structural integrity for the skeleton,” says Gbolahan Okubadejo, M.D., a spine surgeon and head of The Institute for Comprehensive Spine Care in the New York City area. “Calcium combines with other minerals like phosphorus to provide structure and strength for our bones.” If you aren’t getting enough calcium either from your diet or through supplementation, your body may need to pull this structural calcium from your bones to use for other critical functions like muscle contraction and nerve signaling, explains Brynna Connor, M.D., a family medicine physician in Austin and a healthcare ambassador at NorthwestPharmacy.com. “Over time, this can weaken the bones,” she adds.

What’s more, the cellular makeup of your bones is constantly changing throughout your life through a process known as bone remodeling. “This is the lifelong process in which old or damaged bone tissue is removed and replaced by new, healthy bone,” says Dr. Connor. Calcium is vital to this process, she notes. All told, research suggests that low calcium intake is tied to an increased risk of osteoporosis, a condition characterized by low bone density that makes you more prone to fractures.

Magnesium is also an essential part of bone health, says Dr. Connor. “It’s a key structural component of bone, helping the body to create, shape, and strengthen bone tissue,” she explains. Dr. Okubadejo adds that the mineral also helps control bone remodeling, preventing bone from becoming too fragile or brittle.

But perhaps more important is the way magnesium helps regulate calcium and vitamin D levels. “Magnesium helps convert vitamin D3 into its active form, which is necessary to facilitate the absorption of calcium,” explains Dr. Connor. “It also aids in the regulation of calcium transport throughout the body, making sure that calcium gets absorbed into the bones and doesn’t calcify in the soft tissues.” According to a study in the Clinical Kidney Journal, magnesium deficiency may lead to reduced concentrations of vitamin D in the body—and separate research in the International Journal of Molecular Sciences explains that side effects of vitamin D deficiency may include weakened bones and an increased risk of osteoporosis.

In other words, while calcium and vitamin D play more direct roles in maintaining bone health, they are not able to carry out their bone-supportive functions without sufficient magnesium.

If you have concerns about your bone health, the first thing you should do is discuss them with your doctor. They may recommend eating more calcium-rich foods, such as dairy, leafy greens, and chia seeds, or magnesium-rich foods, like pumpkin seeds, almonds, and brown rice. But if you and your healthcare provider determine that supplementation might be helpful, there are some possible side effects and interactions you need to know.

Taking too much calcium may cause constipation, gas, or bloating, Dr. Okubadejo says. “Some patients have also had issues with kidney stones and buildup of calcium in arteries,” he adds. Determining the appropriate dose with your doctor can help mitigate these effects. “Calcium supplements can potentially interact with some medications, including antibiotics, lithium, HIV inhibitors, and thyroid hormone treatments,” says Dr. Connor, so make sure to discuss any meds you’re taking with your provider as well.

The most common side effect of magnesium supplementation is gastrointestinal discomfort, which can vary based on the type of magnesium you are taking and the dose. Repeatedly exceeding 350 milligrams of supplemental magnesium daily may cause more serious side effects, says Dr. Connor, including low blood pressure, confusion, difficulty breathing, and an irregular heart rate, so taking the appropriate dose is key. “Magnesium can also interact with several medications, including some antibiotics, some diabetes medications, bisphosphonates, diuretics, and proton pump inhibitors,” Dr. Connor adds.

If you’re comparing calcium and magnesium for bone health, Dr. Okubadejo says there is a clear winner. “When it comes to bone health, calcium is more important as it directly leads to strengthened bone density, which overall matters most for healthy aging,” he explains. But getting enough magnesium (and enough vitamin D) as well will help ensure your body is able to effectively use the calcium you consume to support strong, healthy bones as you get older. Talking to your doctor about your specific needs is the best way to make sure you’re giving your bones and your body everything they need.

Dietary supplements are products intended to supplement the diet. They are not medicines and are not intended to treat, diagnose, mitigate, prevent, or cure diseases. Be cautious about taking dietary supplements if you are pregnant or nursing. Also, be careful about giving supplements to a child, unless recommended by their healthcare provider.