Written by Cara Rosenbloom, RD | Reviewed by Katie E. Golden, MD
Published on July 8, 2024
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 can be caused by not getting enough calcium from your diet. Another common cause is abnormal parathyroid hormone levels and it can be treated by increasing calcium intake through food or supplements.
nortonrsx/iStock via Getty Images Plus
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.
But many people in the U.S. — almost half of them — don’t meet their average daily requirement for calcium. This puts them at 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.
Why is calcium important?
Calcium is an essential mineral in your diet. It’s the most abundant mineral in the human body. It plays a role in:
The structure of bones, teeth, and body tissues
Muscle function
Blood vessel function
Blood clotting
Nerve signaling
Hormone secretion
Normal heart rhythms
Most of the calcium in the body is stored in the bones. When other parts of the body require calcium, they borrow it from your bones. You need to consume foods, drinks, or supplements with calcium daily to ensure the body gets enough.
Adult males (ages 19 to 70) require 1,000 mg calcium per day. This amount increases to 1,200 mg over age 70. Adult females (ages 19 to 50) need 1,000 mg calcium per day. This increases to 1,200 mg per day for those over the age of 50.
Calcium requirements are higher for females at age 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 is the definition of calcium deficiency?
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 that 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 is 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
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, you’re at increased risk for calcium deficiency.
Other reasons for calcium deficiency include:
Low levels of parathyroid hormone
Low levels of magnesium
Vitamin D deficiency
High phosphate levels in the blood
Kidney disease, which can affect phosphate and vitamin D levels
Pancreatitis
Certain medications that get in the way of calcium absorption
What are the earliest signs 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.
Symptoms are more likely when blood calcium levels are below 7.5 mg/dL, or when it drops quickly. If it’s dropping gradually over time, the body has a longer time to adjust to it and may produce fewer symptoms.
Since calcium is so abundant in the body, symptoms can affect all parts of the body once they do appear. Some possible symptoms of hypocalcemia include:
Tingling around the mouth
Numbness and tingling in hands and feet
Muscle spasms, especially in the hands and feet
Wheezing
Irritability
Depression
Fatigue
Coarse hair
Brittle nails and dry skin
Heart arrhythmias
Memory loss
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 it can lead to:
Osteoporosis (brittle bones)
Osteopenia (reduced minerals in bones)
Osteomalacia (soft bones)
Increased risk of falls and fractures
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 (mg) |
| Yogurt, plain | 1 cup | 488 mg |
| Kefir | 1 cup | 317 mg |
| Milk (non-fat, 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 (mg) |
| Tofu, prepared with calcium sulfate | ½ cup | 434 mg |
| Fortified milk alternatives (almond, rice, etc.) | 1 cup | 280-440 mg |
| Fortified orange or grapefruit juice | 1 cup | 350 mg |
| Sardines, canned | 3 oz | 325 mg |
| Fortified soy beverage | 1 cup | 300 mg |
| Fortified soy yogurt | 1 cup | 300 mg |
| Spinach, mustard greens, or collard greens | 1 cup, cooked | 250-280 mg |
| Salmon, canned with bones | 3 oz | 180 mg |
| Kale, bok choy, or turnip greens | 1 cup, cooked | 175-200 mg |
| Tahini (sesame seed paste) | 1 tbsp | 154 mg |
While many non-dairy foods contain calcium, they may also contain factors 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.
What should you do if you think you have calcium deficiency?
Speak with your healthcare professional if you have the symptoms of calcium deficiency or concern about your calcium intake. They can perform medical tests to assess your blood calcium levels, parathyroid hormone levels, and bone density.
If your calcium intake is low, your healthcare professional may recommend high-calcium foods and/or supplements. In addition to calcium, they may recommend supplements that help your body absorb calcium like:
Vitamin D
Magnesium
Phosphorus
The best treatment varies from person to person, based on the cause and any other nutrient deficiencies.
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 of the foods listed in this article, or if you have symptoms of 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 each day.
References
Bove-Fenderson, E., et al. (2015). Hypocalcemic disorders. Best Practice and Research Clinical Endocrinology and Metabolism.
Brown, L. L., et al. (2021). Physiological need for calcium, iron, and folic acid for women of various subpopulations during pregnancy and beyond. Journal of Women’s Health.
Leave a Reply