Calcium is a mineral that’s vital to building strong bones, also playing an important role in how nerves and muscles work.

Calcium is essential for many functions of your body, so an allergy to calcium is highly unlikely. However, it is possible you could be allergic to some compounded ingredients found in calcium supplements.

An allergy to calcium supplements isn’t the same as an intolerance to lactose or an allergy to other proteins present in milk. Even if you’re lactose intolerant, there are still ways to incorporate calcium-containing foods that aren’t likely to trigger your allergy.

Your doctor may use a few words when talking about the symptoms you describe when you take calcium supplements or eat calcium-containing foods. These may include allergy, intolerance, and sensitivity.

A true food allergy is one that causes an immune system response in the body. Something present in the substance triggers an inflammatory reaction in the body. This can sometimes cause life-threatening symptoms.

Food allergy symptoms

  • hives
  • low blood pressure
  • problems breathing
  • swelling of the mouth and airway

The next reaction type is a food intolerance. This is when you eat something and it causes symptoms that usually involve an upset stomach or something digestive-related.

A food intolerance doesn’t trigger your immune system, but it can make you feel bad.

Food intolerance symptoms

  • bloating
  • constipation
  • diarrhea
  • stomach cramping

Lactose intolerance is an example of a common food intolerance.

Some people can also experience food sensitivities. These cause asthma-like symptoms.

Food sensitivity symptoms

  • coughing
  • trouble taking a full, deep breath
  • wheezing

Food additives, like sulfites, can commonly cause food sensitivities.

Because your body must have calcium to survive, it’s unlikely that you have a true calcium allergy where your body launches an immune system response any time you have calcium.

However, it’s possible that you could have an intolerance to calcium types present in supplements or to the additives manufacturers put in the supplements.

Different calcium supplement types include:

Shop for calcium supplements.

Supplements and side effects Calcium carbonate supplements are known to cause gas and constipation that can feel like a food intolerance. Also, all calcium supplements can be coated with substances that contain milk, soy, or wheat proteins as well as dyes that can also cause allergic reactions or intolerances.

Hypercalcemia

You should also ask your doctor if your symptoms could be related to hypercalcemia. Your body can only absorb so much calcium at a time, usually no more than 500 milligrams.

Hypercalcemia symptoms

  • confusion
  • constipation
  • fatigue
  • nausea
  • stomach upset
  • thirst
  • vomiting

These symptoms are very similar to a food intolerance. However, excess calcium (hypercalcemia) can be harmful because it can interfere with your heart rhythm.

You won’t usually get too much calcium by eating calcium-containing foods. Usually, hypercalcemia will occur because you’ve taken too much calcium as a supplement.

Lactose Intolerance

Lactose intolerance and a calcium supplement allergy or intolerance aren’t the same thing.

Lactose is a type of sugar that’s found in dairy foods, such as milk, ice cream, and cheese. Some people lack enzymes to break down lactose, which can cause intolerance symptoms.

Calcium from foods While all lactose-containing foods have calcium, not all calcium-containing foods have lactose. Leafy green vegetables, almonds, beans, and foods fortified with calcium (like orange juice) all contain calcium. If you can eat these foods, but not dairy products, chances are you’re allergic to lactose, not calcium.

If you suspect you may be allergic to calcium supplements or a component of the supplements, the best treatment is to avoid them. Don’t take any supplements that cause you to have severe reactions.

If you’re taking calcium supplements because you have a hard time getting enough calcium in your diet, your doctor may refer you to a registered dietitian to determine how you can get enough calcium from foods.

For example, if you’re lactose intolerant and can’t take calcium supplements, your dietitian can recommend foods that naturally contain calcium that are less likely to cause symptoms.

High-calcium foods

  • almonds
  • canned salmon
  • canned sardines
  • cooked spinach
  • kale
  • kidney beans
  • soybeans
  • white beans

Talk to your doctor about these options to ensure you’re getting enough calcium.

A calcium supplement allergy is very rare. Therefore, traditional testing methods such as a skin prick test wouldn’t be an option.

Instead, a doctor will usually rely on a description of your symptoms when you take certain supplements.

Your doctor may ask you to keep a food diary, describing your symptoms when you eat various foods. If your reaction was following calcium supplementation, your doctor may consider the calcium supplement type and any other substances the supplement is made with.

See your doctor if you’ve had a serious reaction to calcium supplements or calcium-containing foods.

The most serious allergic reaction is anaphylaxis. This usually occurs within minutes of eating a food or taking a supplement.

Anaphylaxis symptoms

  • diarrhea
  • dizziness
  • hives
  • itching
  • low blood pressure
  • nausea
  • problems breathing
  • too-fast pulse
  • vomiting
  • weak pulse

If you’ve had this reaction type, it’s important to meet with your doctor to make sure it doesn’t happen again.

You should also talk to your doctor if you have food intolerance symptoms related to eating calcium-containing foods or taking supplements your doctor has recommended.

What you think is calcium allergy may actually be calcium intolerance or allergy to calcium supplements — either of which can cause unpleasant symptoms such as stomach cramping, nausea, and diarrhea.

These symptoms can affect your ability to get enough calcium. Talk to your doctor about alternatives to calcium supplements and other ways you can increase calcium in your diet.

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