Calcium supplements: What you need to know

Calcium is important for bone health throughout your life. Adequate calcium intake can help prevent osteoporosis, a disease that causes bones to become fragile and more likely to break. Calcium is also needed for your heart, muscles and nerves to work properly. Dairy foods, green leafy vegetables and calcium-fortified foods are high in calcium. A well-balanced diet can help ensure you get the right amount of calcium. However, many Americans do not get enough calcium through diet alone. In fact, postmenopausal women, people who avoid dairy products, such as those who have a lactose intolerance or follow a vegan diet, are likely to need extra calcium. In these cases, your healthcare provider may recommend that you take a calcium supplement.

The specific amount of calcium you'll need from a supplement depends on how much calcium you get through your diet. Adult men and women (19–50 years) need 1,000 mg of calcium per day from all sources. Women 51 years and older and men 71 years and older need 1,200 mg of calcium each day.

Calcium supplements come in different forms, including tablets, capsules, chews, liquids and powders. Calcium carbonate and calcium citrate are the most common forms of calcium dietary supplements.

Calcium carbonate has the highest amount of calcium. Calcium carbonate should be taken with food for optimal absorption. This is because calcium carbonate depends on stomach acid for its absorption. Calcium carbonate appears to be more likely to cause minor side effects, such as gas, bloating and constipation. Calcium carbonate usually costs less than other forms of calcium.

Calcium citrate is more easily absorbed and can be taken with or without food, although it is better to take with food, especially to help avoid side effects. Calcium citrate is often the form of calcium recommended for people who have low levels of stomach acid, a condition more common among adults 50 years and older. Calcium citrate may also be recommended for those taking medicines to control stomach acid. Calcium citrate is also the form of calcium often recommended for people with irritable bowel syndrome or celiac disease.

According to the National Institutes of Health, calcium absorption is best when a person consumes no more than 500 mg at one time. If you take 1,000 mg of calcium per day from supplements, you should split the dose and only take half of it at a time rather than take it all at once.

Healthcare professionals advise that you should not take more than the recommended amount of calcium per day. High levels of calcium in your blood from supplements can lead to kidney problems, such as kidney stones. Some studies suggest that high calcium intake increases the risk of heart disease and prostate cancer, although further research is needed to understand the possible link.

Calcium supplements may also interact with certain prescription medications, such as blood pressure medication, synthetic thyroid hormones and antibiotics, so it is important to speak with your healthcare professional or pharmacist before starting any supplements.

Some people simply prefer liquid calcium supplements. Calcium supplement pills are usually larger and may be difficult for some people to swallow, especially children. Liquid calcium supplements can be mixed with fruit juice, if needed.

If your child's healthcare provider recommends a calcium supplement, it's important that they take it as directed. Kids need calcium to support their growing bones. Children who get enough calcium start their adult lives with the strongest bones possible, protecting them against bone loss later in life. The American Academy of Pediatrics recommends the following daily calcium intake based on age:

In addition to calcium, vitamin D and magnesium are necessary for bone health. Calcium supplements combined with magnesium supplements are available. Magnesium converts vitamin D into its active form so it can help the body absorb calcium.

When choosing a calcium supplement, or any supplement, be sure to check labels for the United States Pharmacopeia’s (USP) symbol, indicating it is verified. Be sure to check with your pharmacist or healthcare professional if you have any questions about your calcium supplement.
 

Published December 2020.
Clinically reviewed and updated by Rebeca Thomas, BSN, RN, CPHQ, December 2022.