Calcium is an important mineral for the body and overall health. It helps improve bone, heart, and gastrointestinal (GI) health. Calcium may interact with supplements you are taking, like iron, zinc, magnesium, and vitamin D.
Iron is a mineral found in food products and as a dietary supplement. The mineral plays an important role in muscle and tissue health, as well as moving oxygen from your lungs throughout your body. Lean meats, seafood, nuts, and beans are dietary sources of iron.
Taking calcium (whether from food or supplements) can lower how much iron your body absorbs. This is because calcium interferes with iron transport in your intestines. This means your body will temporarily absorb less iron.
It is typically fine to take these together if they are both in a multivitamin. This is because you are receiving smaller doses of both minerals. If you are taking two separate supplements, you should space out when you take each. Take iron by itself on an empty stomach, or at least an hour before you eat a meal. This is especially important if you have low iron or need extra iron to help treat anemia. Calcium is usually best absorbed with a meal.
Zinc is a mineral often found in cold medicines and other over-the-counter (OTC) products. Zinc helps support a healthy immune system, wound healing, and cellular health.
Calcium and zinc also compete for absorption in your gut, so taking them together can lower how much your body absorbs of each mineral. You are unlikely to have this effect if you have enough zinc stored in your body.
Because the doses are often small, it is okay to take a multivitamin that has calcium and zinc. However, if you are taking them as individual supplements, separate calcium and zinc supplements from each other.
It’s best to take your calcium supplement with a meal. You can take zinc with or without food, but avoid taking it with calcium-rich meals. This includes milk, yogurt, cheese, and certain vegetables.
Magnesium is a mineral that plays a role in hundreds of body and cellular processes. Magnesium is important for bone, muscle, and heart health, as well as many other conditions.
It is safe to take magnesium and calcium together. However, it may be best to separate when you take each. Both minerals compete with each other to be absorbed in the body. High calcium doses (higher than 2,600 milligrams a day) can also affect your magnesium level, especially if your magnesium levels are already low.
Vitamin D is found in certain foods and supplements, and your body produces it naturally when sunshine hits your skin. Vitamin D is important for bone, heart, and mental health.
In general, it is safe to take vitamin D and calcium together. However, taking calcium with high doses of vitamin D (long-term intake of doses larger than 4,000 international units (IUs) per day) can raise your risk for dangerously high calcium levels in your blood. Taking both supplements together raises the amount of calcium absorbed and broken down in your gut. This will raise your blood calcium levels.
High calcium levels (hypercalcemia) can cause symptoms like nausea, vomiting, constipation, muscle weakness, and changes in brain function.
Calcium may also interact with medications, including:
- Quinolone antibiotics: Taking calcium with quinolone antibiotics can lower how well your body absorbs the antibiotic. Examples of quinolone antibiotics are Cipro (ciprofloxacin), Levaquin (levofloxacin), and Avelox (moxifloxacin). If taking a quinolone antibiotic and calcium, be sure to take the antibiotic two hours before or two hours after taking the calcium supplement.
- Thyroid medications: Calcium can affect how well your body absorbs thyroid medications. This may include Synthroid (levothyroxine) and other thyroid drugs. If taking both, avoid taking thyroid medication within four hours of a calcium supplement.
- Bisphosphonates: Calcium may lower how well your body absorbs bisphosphonates. These drugs, like Fosamax (alendronate), are used to treat osteoporosis (weak and brittle bones). To avoid this interaction, take bisphosphonates at least 30 minutes before a calcium supplement.
