Is Calcium Carbonate Vegan? Find Out Once And For All!

How often have you come across the ingredient calcium carbonate in foods and supplements? It’s the most common form of calcium, and I see it a lot of times.

And since calcium is an important mineral for human health, I just had to do my thing. I did my own research.

So the question is: is calcium carbonate vegan?

Guess what I found out? It actually depends on the source. That can sound tricky, I know. So how do we vegans know if we’re looking at a vegan calcium carbonate?

Tons of questions, I know. So let me start.

What Is Calcium Carbonate?

Calcium comes in many forms, but Calcium Carbonate is the most common form you’ll find. It has many uses in food and medical industry alone, so its scrutiny is a must for vegans. Essentially, it is made of carbon, oxygen, and calcium.

When a dietary supplementation of calcium is needed or recommended, calcium carbonate is also the usual choice. It is also cheaper than calcium citrate, the other form of calcium which you’ll also see in supplements.

To give you a better idea, here’s a short comparison:To give you a better idea, here’s a short comparison:


Other forms of calcium and their elemental calcium content:

  • Calcium phosphate 38.7%
  • Plant calcium 30%
  • MCHC calcium 25%
  • Calcium lactate 13%
  • Calcium ascorbate 10%
  • Calcium gluconate 9%

Calcium Carbonate In Food Products

As the most widely available form of dietary calcium, it makes a frequent appearance in many food and supplement labels.

Pharmaceutical products:

  • Calcium supplements
  • Antacids
  • Anti-hypertensive medicines

Fortified foods:

  • Cereals
  • Cereal bars
  • Milk alternatives
  • Baked goods
  • Oatmeal
  • Fruit juice
  • Crackers

For vegans, it’s worth noting that most calcium carbonates on food and medicine labels don’t mention its source. This makes calcium carbonate kind of shady, which is why I personally just choose ones with an actual vegan label.

Actual calcium supplements, however, do include their sources. Well, most of them.

Importance Of Calcium In Health And Its Supplementation: Are There Risks Too?

Calcium is one of the most popular nutrients around. I bet even kids know how important it is for health. Our body uses it a lot, in many ways, which is why we also need it in large amounts. In the following daily amounts, to be exact:

  • Women below 50 years old: 1,000 mg
  • Women above 50 years old: 1,200 mg
  • Men below 70 years old: 1,000 mg
  • Men above 70 years old: 1,200 mg

Children will of course require lower amounts. These numbers may also vary if you have medical conditions and diseases that affect the body’s ability to absorb and use calcium.

For example, pregnancy, thyroid disease, etc.. So it’s always best to consult your doctor first if you’re thinking about supplementation.

Meeting one’s daily calcium needs is of course a must to maintain its functions in the following:

  • Bone and teeth development and health
  • Heartbeat regulation
  • Brain activity
  • Muscle contraction
  • Cellular fluid balance
  • Blood clotting
  • Nerve-impulse transmission
  • Regulation of hormones

Additionally, optimum calcium levels in the body may also provide the following benefits:

  • Efficient fat loss
  • Lower colon cancer risk
  • Improved metabolic markers

Now, just a reminder. This doesn’t mean that you can go all out on calcium just to get these benefits. Like most nutrients, calcium has an upper limit which starts at 2000 mg a day.

This upper limit indicates a potentially toxic level, which means anything above it only poses health risks and not benefits.

Excessive consumption of calcium comes with the following risks:

  • Heart disease (heart attack and stroke)
  • Prostate cancer
  • Kidney stone
  • Hypercalcemia (high blood calcium levels)
  • Malabsorption of iron and zinc
  • Constipation
  • Calcium buildup in soft tissues (calcification)

Calcium is known to interfere with zinc and iron. So if you’re taking those supplements, it’s best to take them a few hours apart from each other.

Similarly, if you are taking any medications, check with your physician first about any possible drug interactions.

Experts also recommend that it is ideal to split up your daily dose into two. This is because the body can’t absorb large doses all at once. So if you want to get 1000 mg daily, take a 500 mg dose twice a day instead.


Calcium Carbonate Sources

Now where do manufacturers get the calcium carbonate that they use in food and pharmaceutical products? There are 3 kinds of sources:

1. Animal Sources

  • Marine shells (from oyster
  • Animal bones
  • Egg shells

2. Non-Animal Sources

  • Limestone
  • Marble
  • Chalk
  • Dolomite

3. Synthetic Sources

Like most chemical compounds, calcium carbonate can also be produced synthetically. It may also go by the name PCC or Precipitated Calcium Carbonate.

However, I can’t say PCCs are purely synthetic though, since its production often requires limestones too. The limestones undergo a purification process, which improves particle quality, turning it into a high grade calcium carbonate.

Strict Vegans Against Calcium From Rocks

This is probably not a popular idea, but there are stricter vegans who look at rock calcium as non-vegan. This is because rocks are a product of sedimentation of animal shells and skeletons over millions of years.

What does that mean exactly?

In simpler terms, rocks are made up of crushed animal bones and shells that have accumulated over millions of years. This of course also includes varying amounts of sand, clay, silt, and dozens of other minerals.

For some vegans, it means it makes no difference with calcium minerals from marine shells, animal bones, and the likes.

So strictly speaking, calcium carbonate from rocks are technically NOT vegan. However, for some vegans, the amount of animal remains in it is negligible enough for them to just shrug it off. So again, the decision is up to you.

Other arguments also say that rocks are not for human consumption. So getting calcium from limestones and other popular calcium-rich rocks can be questionable for some.

The thing is, there are no sufficient studies to support this argument. So you can take that info with a grain of salt.

Finally, like I say, us vegans can have our own preferences. If you ask me, I’d rather get my calcium from foods.

Vegan Calcium Supplement Brands

There’s another issue with calcium from marine shells and rocks: the lead content. In particular, significant lead content has been found in calcium supplements made from oyster shells, dolomite, and bonemeal.

But I guess the good news is, there are now manufacturing processes that can reduce lead content.

Lead can also be found in some plant calcium supplements like the popular AlgaeCal. However, a study shows that there are no significant toxicities from it. Calcium is also know to inhibit lead absorption. Most likely, this is the reason why low levels of lead in calcium supplements become insignificant.

But hey, you still have to be careful! I’m pretty sure calcium won’t do much when that lead content is too high.

Now onto more important matters! Here are some totally vegan-friendly plant calcium supplements for all you vegans like me:

Just a wee bit of info: Plant calcium is made up of 4 different calcium molecules. Namely:

  1. Calcium hydroxide
  2. Calcium chloride
  3. Calcium sulfate
  4. Calcium carbonate

Most of these plant calcium supplements also contain other beneficial nutrients such as magnesium and vitamin D, among others.

They all make it easier for the body to absorb, use, and store calcium. With marine algae being the most popular source of calcium supplements these days, we vegans are in luck!

Vegan Food Sources Of Calcium

On a nutritional standpoint, ultimately, getting calcium from food is always better than supplements. Dietary calcium supplements can be like a shortcut yes, but our body uses calcium from real food much better.

Now which foods can we vegans get the most calcium from? Take note of these ones!

  • Beans
  • Lentils
  • Almonds
  • Leafy dark greens (spinach, kale, collard greens, turnip greens)
  • Rhubarb
  • Fortified cereals and drinks
  • Amaranth grain
  • Tofu and edamame
  • Figs
  • Seeds (from poppy, sesame, celery, chia)
  • Seaweeds

If you’re looking for the most “body-friendly” calcium, then foods are your best bet. The vegan world is quite abundant with high-calcium foods, so no one can say vegans get short in calcium!


Calcium carbonate can come from both animal and non-animal sources. However, with a little argument over rock calcium’s real vegan status, you’re probably better off with plant calciums.

Or better yet, just keep tossing some high-calcium veggies on your plate!

Are you taking a vegan calcium supplement? Which one is your favorite so far? Let me know on the comment section below. And don’t forget to share this article in your favorite social media platform.

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