What Happens to Your Bone Health When You Take Vitamin D and Calcium Together?

Calcium and vitamin D are both essential nutrients for maintaining strong, healthy bones. And while each plays a different role in bone health, experts say they work better when taken together.

What Calcium and Vitamin D Do In the Body

Calcium is a mineral that gives bones their structure and strength, while vitamin D is a hormone that supports bone growth, according to Natalie Allen, RD, a clinical associate professor of nutrition and dietetics in the School of Health Sciences at Missouri State University.

Adults generally need 1,000-1,200 mg of calcium daily, while most adults need 600-800 IU of vitamin D daily, though some may need more depending on age, skin tone, or medical conditions.

“Calcium is the main building block that gives bones their structure and strength,” said Diana Guevara, MPH, RD, a community health education specialist at The University of Texas Health Science Center’s School of Public Health.

“It is also used throughout other parts of the body, so if we do not get enough calcium, our bodies could be forced to pull calcium from our bones, leading to osteoporosis and a higher risk of fractures.”

Why You Should Take Calcium and Vitamin D Together

When it comes to bone health, vitamin D’s main role is to facilitate calcium absorption in the gut.

“Without enough vitamin D, calcium cannot do its job well,” Allen said. “Pairing them ensures you’re getting the bone-strengthening benefit from calcium.”

Research has shown that taking vitamin D and calcium supplements together can improve bone mineral density more than taking either supplement alone, specifically in older adults and post-menopausal women.

“Activated vitamin D binds to a receptor in the gut to start the process of absorbing calcium from food or supplements into the body,” Guevara explained.

Is It Better to Eat Nutrient-Rich Foods or Take Supplements?

It’s always best to aim to get nutrients from food first if possible, Guevara said, as nutrients in food are easier for the body to absorb and utilize.

This may mean incorporating more calcium-rich foods such as:

• Dairy foods
• Leafy greens
• Fish with bones (such as sardines or canned salmon)

It may also mean consuming more vitamin D-rich foods such as:

• Fatty fish
• Eggs
• Mushrooms
• Fortified milk

However, Allen said food sources for vitamin D are limited as these foods only contain small amounts of the hormone, so supplements are often needed to help people get enough.

Sunlight can help your body make vitamin D naturally, but too much sun exposure poses other health risks such as skin cancer.

“About 10 to 30 minutes of sun exposure, a few times per week, can be enough for some people, depending on location and season,” she said. “Darker skin tones may need more time in the sun to produce the same amount of vitamin D.”

When You May Need a Supplement

If you spend most of your time indoors or wear sunscreen daily, which Allen notes is important for skin protection, a supplement is often the most reliable way to meet your needs.

If you are going to take a supplement, Guevara said it is important to note that the upper limit of vitamin D for adults is 4,000IU per day. Since vitamin D is a fat-soluble vitamin, it can be stored in the body and build up over time.

Before starting any new supplements, always talk to your health care provider to discuss what’s right for your unique health and needs.