Plant-Based Calcium | Is Calcium Carbonate Vegan?

The short answer to “is calcium carbonate vegan?”…Well, it depends on the source.

To answer this question adequately, a little background information on calcium carbonate will tell you why this answer is not a simple one. But don’t worry – I did the hard work for you.

What Is Calcium Carbonate? 

Calcium carbonate is a form of calcium, the most abundant mineral in the human body. 

It is one of the main types of calcium used as a food additive in cereals, plant-based milk, and other calcium-enriched foods.2 

Calcium carbonate is the active ingredient in calcium supplements and antacid medications (Tums).

Patients with chronic kidney disease may use it as a phosphate binder to maintain normal levels within the blood. 2 

Bone tissue stores most of the calcium in the body. Adequate calcium intake during childhood forms strong, dense bones. As a result, you will have better calcium stores later in life.

Calcium not stored in bone tissue exists in the blood, muscle, and other fluids. The parathyroid hormone maintains this calcium concentration through reabsorption and deposition of bone tissue.

In other words, the body uses the movement of calcium between bone tissue (storage) and other tissues (usage) to maintain proper levels.

The bone tissue continues to reabsorb and deposit calcium throughout life. During growth periods, the formation of bone exceeds the rate of bone breakdown. As a result, you build strong, dense bones if you consume enough calcium.

On the other hand, when a person reaches ages 50 to 60, the rate of bone breakdown exceeds that of bone formation.1 Consequently, your fall risk and bone injury risk (fractures) increase as you age due to lower bone density.

While calcium exists largely in the bone tissue, it also has functions in blood clotting, normal heart functioning, nerve transmission, and smooth muscle contractions.

So Is Calcium Carbonate Vegan? 

There is no simple answer, as it depends on the source. Non-vegan calcium carbonate may come from a variety of shells, like egg and oyster shells.  

Vegan forms of calcium carbonate come from limestone, chalk, marble, and other types of rock found in nature. 2 

The ‘rock,’ and therefore vegan, sources of calcium carbonate are more available, so it is likely that calcium-fortified foods and calcium carbonate supplements contain the plant-based type.   

Unfortunately, it is hard to be certain unless the label specifies it is vegan.

The good news is that you can skip the supplement route entirely and focus on eating more whole foods with naturally occurring calcium.

Check out the list of these foods below! 

Vegan Sources of Calcium

  • Broccoli 
  • Chinese (Napa) cabbage 
  • Fortified orange juice 
  • Fortified plant milk 
  • Kale 
  • Leafy green vegetables  
  • Legumes 
  • Tofu made with calcium sulfate 

How Much Calcium Do You Need?

  • 1000 milligrams per day for males aged 19-71 years old 
  • 1000 milligrams per day for females aged 19-50 years old 
  • 1200 milligrams per day for males aged 71+ years old 
  • 1200 milligrams per day for females aged 51+ years old 

One cup of calcium-fortified soymilk contains 299 milligrams of calcium, for reference. Always try to get your nutrient requirements from food before supplements, when possible. 1 

Vitamin D and Calcium 

Vitamin D aids in the absorption of calcium, so making sure to get adequate vitamin D intake through the sun, fortified foods, or supplements is also important.

Additionally, the presence of acid also increases calcium absorption. Consider adding lemon juice to your green leafy vegetables for the extra absorption boost!

Calcium Deficiency

Hypocalcemia, or low levels of circulating blood calcium, may occur if a person has medical conditions like kidney failure, surgical removal of the stomach, or diuretic medications. 1 

These conditions interfere with calcium regulation in the body through poor absorption, reabsorption, or removal of calcium from the body. 

Symptoms of hypocalcemia first appear as symptoms such as numbness of the fingers, muscle cramps, fatigue, or poor appetite. 

Over time, inadequate calcium intake results in the body using the calcium stores in the bone. A person may develop conditions like osteopenia (low bone density) and osteoporosis because of this process. 

Calcium deficiency is more likely to occur as people age since requirements are higher later in life due to the change in rates of reabsorption and deposition of bone tissue.  

Too Much Calcium

If your diet is composed of a lot of calcium-fortified foods, foods naturally high in calcium, or supplements containing calcium, you may be at risk of hypercalcemia (high levels of circulating blood calcium), or toxicity from calcium.  

Toxicity can be fatal, so it is best to get your levels checked by a doctor if you have concerns about currently consuming a very high calcium diet. 


The Federal Department of Agriculture (FDA) lists calcium carbonate as a food additive, meaning it is Generally Recognized As Safe (GRAS) for consumption. 

Food applications, like Cronometer, are a great way to estimate your daily intake of micronutrients, like calcium, and can be a helpful tool in monitoring your health.  

In Summary

Is calcium carbonate vegan? It may be, depending on where it was sourced. Choose supplements and food products labeled ‘vegan’ if you want to be sure.

Adequate levels of calcium are essential to maintain balance within the body. To avoid conditions like osteoporosis, it is important to get adequate calcium during growth periods and to continue to meet the RDA’s as you age.

Choosing whole food sources of calcium (refer to list above) provide both calcium and other beneficial components, like phytonutrients, and are a great addition to your daily food intake.

A green vegetable a day keeps the doctor away! And don’t forget the splash of lemon.

Sources of Information

  1. Office of Dietary Supplements. (2021). Calcium: Fact Sheet for Health Professionals [Fact Sheet]. National Institutes of Health. 
  2. PubChem. (2004). Calcium Carbonate. National Library of Medicine. 

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