Calcium Phosphate vs. Calcium Carbonate: What's the Difference?

Calcium phosphate is a dietary supplement used to treat calcium deficiency. Specifically, it is naturally occurring calcium that has bonded to phosphate. For dietary purposes, it is available in tablet, powder, and chewable forms. It typically contains an impressive 39% calcium, while other supplements have only 20%.

An alternative to calcium phosphate, calcium carbonate — the latter is a mineral in limestone — has the added benefits of an antacid to neutralize stomach acid. It is one of the most common options, as it dissolves well, for rapid absorption. Calcium carbonate is available in both capsule and powder form. Typically, it is 40% calcium by weight.

Calcium supplements such as calcium phosphate and calcium carbonate provide several benefits. While the primary use is to build and maintain strong bones and prevent osteoporosis, that is not all they can achieve. Combining calcium supplements with vitamin D (which aids in the absorption of calcium) has been found to protect against cancer, diabetes, and high blood pressure.

Every person, young and old, should be meeting a daily minimum requirement of calcium. Averages change based on age and sex. For those who are not reaching this amount through natural sources such as dairy and leafy greens, a doctor may recommend a calcium supplement. In particular, the following groups may need calcium supplementation:

• Vegans
• Lactose intolerant people
• Anyone receiving long-term corticosteroid treatment
• Those with a diet high in protein or sodium
• Those with bowel or digestive issues

While any calcium delivery system has its advantages, phosphate is required for optimal bone health, making calcium phosphate ideal for those with a deficiency, typically associated with celiac disease, kidney issues, alcohol disorder, and those who take too many antacids. Another benefit of calcium phosphate is that the amount of calcium is higher than most other supplements.

While phosphate is essential for bone health, too much can lead to osteoporosis or issues with kidney function. Because most people get sufficient phosphates through diet, adding more via calcium supplements may cause issues. Because of this, calcium phosphate may only be appropriate for those with other health issues. Be sure to discuss any supplements or medications with a doctor before adding them to a daily plan.

Calcium carbonate can be used in the treatment of many disorders including dyspepsia, hungry bone syndrome, hypocalcemia, and tumor lysis syndrome. Similar to calcium phosphate, it has a high volume of calcium, making it ideal for bone deficiencies. It can also be used to decrease the levels of phosphates in blood. Additionally, it is the cheapest calcium supplement on the market and can double as an antacid.

While the benefits of calcium carbonate are numerous, it is important to note that not all advantages have been empirically proven. Additionally, it requires vitamin D to be effective. A doctor can confirm what calcium supplement is best for each patient's needs.

Both calcium phosphate and calcium carbonate can effectively increase calcium in the body, containing higher percentages of calcium than many other supplements. That said, both can react negatively with other medications. Regardless of the supplement, it is important to discuss it with a doctor prior to use.

Both supplements are available in different forms for ease of use and are absorbed more effectively with vitamin D.

Supplements are good for people who have limitations to their diet that prevent them getting enough of a vital nutrient, or those with deficiencies preventing their bodies from properly absorbing a nutrient. However, natural sources are usually the best option, and in the case of calcium, there are many choices. Excellent natural sources of calcium — that could remove the need for a supplement — include

• Milk
• Greens like okra and kale
• Bone-in fish, such as sardines and canned salmon
• Soy products fortified with calcium