Key takeaways:
Calcium is an essential mineral that you can get from foods, drinks, and supplements. Good sources of calcium include dairy products, leafy greens, and calcium-fortified drinks.
Signs of calcium deficiency include tingling, muscle spasms, and heart arrhythmias. A serious long-term effect of calcium deficiency is osteoporosis, a bone disease.
Calcium deficiency syndrome or hypocalcemia can be caused by not getting enough calcium from your diet. Another common cause is abnormal parathyroid hormone levels. It can be treated by increasing calcium intake through food or supplements.
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Calcium is an essential mineral that you need to consume daily. That’s easy to do if you love milk and yogurt, which contain lots of calcium. Calcium plays an important role in bone, muscle, nerve, and blood vessel health.
But many people in the U.S. — almost 50% — don’t meet their average daily requirement for calcium. And not getting enough calcium increases risk for calcium deficiency, which can lead to bone diseases, if left untreated.
You can prevent calcium deficiency by consuming calcium-rich foods and drinks, or using supplements, when needed.
Learn about the signs of calcium deficiency and how you can ensure you get enough calcium each day.
What is calcium deficiency (hypocalcemia)?
Calcium deficiency is when there’s a low level of calcium in your blood. It’s also called hypocalcemia.
The normal range of calcium in your blood is typically 8.8 mg/dL to 10.4 mg/dL in healthy people. (Note: The normal range can vary from lab to lab.)
Sometimes, calcium is measured with a lab test called ionized calcium. This measures the calcium in the blood that’s active and available for your body to use. For this reason, healthcare professionals sometimes use it as a more sensitive measure of calcium deficiency. A normal ionized calcium level is 4.6 mg/dL to 5.3 mg/dL.
But you don’t need an ionized calcium level to diagnose calcium deficiency. Calcium deficiency is usually defined as either:
Total calcium level: below 8.5 mg/dL
Ionized calcium: below 4.61 mg/dL
Low calcium and medications: If your calcium is low, check your medications. Some medicines — like diuretics and lithium — can lead to hypocalcemia (calcium deficiency).
Best foods for bone health: These foods that are high in calcium and vitamin D can help keep your bones strong.
Calcium supplements: Learn the differences between the two of the most common types of calcium supplements.
What are the signs and symptoms of calcium deficiency?
Early on, calcium deficiency may have no symptoms. It takes time for low calcium levels to cause symptoms. So, it may go undetected. The symptoms really depend on how low calcium levels are and how quickly the blood level is dropping.
If the calcium level drops gradually over time, the body has a longer time to adjust to it and may produce fewer signs. Symptoms are more likely when blood calcium levels are below 7.5 mg/dL, or when it drops quickly.
Since calcium is so abundant in the body, symptoms can affect all parts of the body once they do appear.
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Possible signs and symptoms of hypocalcemia include:
Tingling around the mouth
Numbness and tingling in hands and feet
Muscle cramps or spasms, especially in the hands and feet
Wheezing, tetany, throat spasms, or breathing issues
Irritability
Fatigue
Coarse hair
Brittle nails and dry skin
Hallucinations, delirium, or confusion
Dental issues (tooth decay and loosening of teeth)
Low blood pressure
Effects of calcium deficiency on bone
Low calcium can also lead to problems with your bones. The body tightly controls calcium levels in your blood. If you don’t get enough calcium daily to maintain blood levels, it’ll be borrowed from your bones. This makes bones weak.
Over time hypocalcemia can lead to:
Osteoporosis (brittle bones)
Osteopenia (reduced minerals in bones)
Osteomalacia (soft bones)
Increased risk of falls and fractures
How much calcium do you need per day?
Adult males (ages 19 to 70) require 1,000 mg of calcium per day. This amount increases to 1,200 mg over age 70.
Adult females (ages 19 to 50) need 1,000 mg of calcium per day. This increases to 1,200 mg per day for those over the age of 50.
Calcium requirements are higher for females over 50 because of their increased risk for osteoporosis — a bone disease marked by low bone mass. Menopause also decreases the ability for your body to absorb calcium.
What causes calcium deficiency?
The simplest cause of calcium deficiency is low calcium intake. This happens if you don’t consume enough calcium from foods, drinks, or supplements. If you avoid dairy products — due to preference or lactose intolerance — you’re at increased risk for calcium deficiency.
Other reasons for calcium deficiency include:
Low levels of parathyroid hormone
High phosphate levels in the blood
Kidney disease, which can affect phosphate and vitamin D levels
Certain medications that get in the way of calcium absorption
What are the best sources of calcium?
Dairy foods — such as milk, cheese, and yogurt — are the best sources of calcium. If you don’t eat dairy, you can choose other calcium-rich foods, such as canned salmon, leafy greens, and tofu (made with calcium sulfate).
Here’s the calcium content in some dairy foods.
Food | Amount | Calcium |
|---|---|---|
Yogurt (plain) | 1 cup | 488 mg |
Kefir | 1 cup | 317 mg |
Milk (nonfat, 1%, or 2%) | 1 cup | 305 mg |
Greek yogurt (plain) | 1 cup | 250 mg |
Cottage cheese | 1 cup | 233 mg |
Cheddar or mozzarella cheese | 1 slice (21 g) | 148 mg |
Here’s the calcium content in some non-dairy foods.
Food | Amount | Calcium |
|---|---|---|
Tofu, prepared with calcium sulfate | ½ cup | 434 mg |
Fortified milk alternatives (such as almond or rice beverages) | 1 cup | 280-440 mg |
Fortified soy beverage | 1 cup | 300 mg |
Fortified soy yogurt | 1 cup | 300 mg |
Fortified orange or grapefruit juice | 1 cup | 350 mg |
Sardines (canned) | 3 oz | 325 mg |
Spinach, mustard greens, or collard greens (cooked) | 1 cup | 250-280 mg |
Salmon (canned with bones) | 3 oz | 180 mg |
Kale, bok choy, or turnip greens (cooked) | 1 cup | 175-200 mg |
Tahini (sesame seed paste) | 1 tbsp | 154 mg |
While many nondairy foods contain calcium, they may also contain compounds that hinder calcium absorption. Nutrients, such as phytates and oxalates, can inhibit calcium absorption from foods like leafy greens and soy. That means even if you eat tofu, spinach, or kale, not all of the calcium will be absorbed. Your body is better at absorbing calcium from dairy products.
How is calcium deficiency diagnosed?
Hypocalcemia is diagnosed with a blood test that measures calcium levels. If you have symptoms of calcium deficiency, or if you’re concerned about your calcium intake, reach out to a healthcare professional you trust. They can order a blood test to check your total calcium level. This includes both bound and free calcium in your blood. Some healthcare professionals prefer to measure ionized calcium — the “free” form that’s active and available for your body to use. If either level is low, it means you have hypocalcemia.
Because calcium levels can be affected by albumin, kidney function, and other electrolytes, like magnesium, additional tests are often ordered to help identify the underlying cause.
How is calcium deficiency treated?
Treatment of hypocalcemia depends on how low your calcium levels are, and what’s causing the drop. The goal is to raise the calcium to a safe level and address the underlying cause.
Treatment for hypocalcemia may include:
Oral calcium: If symptoms are mild, low calcium is usually treated with oral supplements, like calcium carbonate or calcium citrate. Vitamin D is often added to help your body absorb the calcium.
IV calcium: For more serious symptoms — muscle spasms, tingling, or abnormal heart rhythms — IV calcium (usually calcium gluconate) may be given in a monitored setting. IV treatment may also be needed if calcium levels drop suddenly, even if symptoms aren’t severe.
Vitamin D and/or magnesium supplements: Vitamin D and magnesium play key roles in maintaining healthy calcium levels. If either one is low, it can make it harder for your calcium level to improve. So, supplements are often added as part of treatment.
Parathyroid hormone: In some cases, hypocalcemia is due to low parathyroid hormone (PTH), a hormone that helps regulate calcium levels. Treatment may include PTH replacement therapy.
Frequently asked questions
You may be at risk for calcium deficiency if you don’t get enough calcium in your diet — for example, if you’re vegan or have lactose intolerance. You're also more likely to have low calcium if you have trouble absorbing it, which can happen with inflammatory bowel disease (IBD) or other digestive conditions.
Other things that can raise your risk for calcium deficiency include:
Kidney disease
Weight-loss surgery
Certain medications, like diuretics or long-term corticosteroids
Low levels of vitamin D or magnesium
Low calcium isn’t usually a sign of cancer. In rare cases, certain cancers — like thyroid or colon cancer — can lead to low calcium levels. But, more often, cancer is linked to high calcium levels. If calcium is low in someone with cancer, it’s often due to treatments like chemotherapy or certain medications, rather than the cancer itself.
It’s hard to say exactly how common calcium deficiency is, because calcium levels aren’t routinely checked. But some evidence suggests that 42% of Americans don’t get enough calcium from their regular diet. So, calcium deficiency is likely fairly common.
You may be at risk for calcium deficiency if you don’t get enough calcium in your diet — for example, if you’re vegan or have lactose intolerance. You're also more likely to have low calcium if you have trouble absorbing it, which can happen with inflammatory bowel disease (IBD) or other digestive conditions.
Other things that can raise your risk for calcium deficiency include:
Kidney disease
Weight-loss surgery
Certain medications, like diuretics or long-term corticosteroids
Low levels of vitamin D or magnesium
Low calcium isn’t usually a sign of cancer. In rare cases, certain cancers — like thyroid or colon cancer — can lead to low calcium levels. But, more often, cancer is linked to high calcium levels. If calcium is low in someone with cancer, it’s often due to treatments like chemotherapy or certain medications, rather than the cancer itself.
It’s hard to say exactly how common calcium deficiency is, because calcium levels aren’t routinely checked. But some evidence suggests that 42% of Americans don’t get enough calcium from their regular diet. So, calcium deficiency is likely fairly common.
The bottom line
Getting enough calcium every day is an important step to protect your bone health. Since calcium is the most abundant mineral in the body, it affects more than just bones. Your heart, brain, and muscles also benefit from getting enough calcium.
If you don’t eat many foods that are high in calcium — like dairy foods, leafy greens, or calcium-fortified beverages — or if you have symptoms of hypocalcemia (calcium deficiency), talk to a healthcare professional. They can help you add calcium-rich foods or supplements to your diet to make sure you get enough calcium each day.
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References
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