Calcium is one of the most well-known minerals and is often the first thing we think of when it comes to bone health. However, calcium is not only a key component of our bones and teeth- it also plays an important role in a variety of bodily functions (NIH, 2022). Several factors can cause our bodies to not receive enough calcium or properly use the calcium we receive through our diets. A deficiency of this mineral can have a significant impact on health and increase the risk for a variety of diseases (Cleveland Clinic, 2023). Read on to learn more about the functions of calcium in our bodies, how much calcium is needed for good health, how to meet your calcium needs, and what can cause a calcium deficiency.

Table of contents

• What is calcium?
• What is calcium’s function in the body?
• How much calcium do I need?
• What is calcium deficiency?
• Causes of calcium deficiency
• Symptoms of calcium deficiency
• Risk groups for calcium deficiency
• Calcium deficiency and other diseases
• Diagnosing calcium deficiency
• How is calcium deficiency treated?
• Can calcium levels in the body be elevated?

What is calcium?

Calcium is an essential mineral that performs many important functions in our bodies. It is the most abundant mineral in the human body, making up to 1.5-2% of our body weight. Much of the calcium in our bodies – about 99 percent – is stored in our bones and teeth (NHS, 2023). Minerals are  naturally occurring, inorganic substances, meaning they do not come from living things. Along with calcium, there are several other minerals that play a crucial role in many biological functions and are essential for human health. These minerals include phosphorus, potassium, sodium, selenium, and magnesium. The human body requires minerals in varying amounts, from trace elements (very small amounts) to bulk elements (in larger amounts) (MedlinePlus, 2022). Although our bodies use calcium all the time, they cannot produce it themselves. Therefore, we must get calcium from food, drinks, or supplements to meet our daily needs. 

What is calcium’s function in the body? 

Calcium plays a role in several important body functions:

1. Building and maintaining bones and teeth:Primarily found in our bones and teeth, calcium is necessary for building and maintaining the strength and structure of our bones. Bones also serve as a reservoir of calcium that can be released into the bloodstream when needed.
2. Muscle function: Calcium is essential for normal muscle function. When a muscle cell is stimulated, calcium flows into the cell and helps the muscle contract. Calcium then escapes from the cell, causing the muscle to relax. These processes are needed for all types of muscle activity, including the function of the heart and the smooth muscle that surrounds our organs.
3. Blood clotting: Calcium plays a key role in blood clotting, the process that reduces bleeding when we are injured and helps repair damaged blood vessels.
4. Nervous system: Calcium is critical to the function of our nervous system. It contributes to the transmission of nerve impulses and enables the release of neurotransmitters, the chemical messengers that enable communication between nerve cells.
5. Metabolism: Calcium plays a role in many metabolic processes and contributes to the regulation of digestion, energy production, and hormone release.

Source: NIH, 2022, Harvard Health, 2023

How much calcium do I need?

The recommended daily allowance for calcium varies by age, gender, and certain life stages. Infants ages 1 to 3 years are recommended to receive 700 mg of calcium per day, while adolescents 9 to 18 years old need about 1300 mg/day due to rapid bone growth during this stage of life. Adults between 19 and 50 years of age and men up to 70 years of age should consume 1000 mg daily. However, older people (over 70 years of age) and women between 51 and 70 years of age are advised to consume 1200 mg per day. Pregnant and lactating women need between 1000 and 1300 mg of calcium per day (NIH, 2021).

How can I meet my calcium needs?

In order to perform all of its important functions, calcium levels in our bodies must be carefully regulated. This is mainly done by hormones such as parathyroid hormone (PTH) and vitamin D. PTH helps control calcium levels in the blood, and vitamin D helps the body absorb calcium from food PTH (Fleet, 2017). However, calcium levels can only be regulated with a sufficient supply.

Calcium is found in a wide variety of foods, both animal and non-animal in origin. A balanced diet that includes a variety of calcium-rich foods is key to good calcium intake.

Foods of animal origin

• Dairy products: Dairy products are one of the best known and most easily absorbed sources of calcium. These include milk, yogurt, cheese, and cottage cheese. Hard cheeses, such as Parmesan, are particularly rich in calcium. 
• Certain types of fish: fish with soft, edible bones, such as sardines and salmon, are an excellent source of calcium. They also contain omega-3 fatty acids, which offer other health benefits

Foods of non-animal origin

• Green leafy vegetables: green leafy vegetables such as kale, spinach, and broccoli are excellent sources of calcium. They also contain a variety of other important nutrients such as vitamin C and iron.
• Legumes: Legumes such as beans and lentils contain a considerable amount of calcium.
• Nuts and seeds: Nuts and seeds, especially almonds and sesame seeds, contain high amounts of calcium.
• Dried figs: Dried figs are rich in calcium and are a delicious way to meet your calcium needs.
• Whole grain products: Whole grain products such as whole wheat bread and brown rice contain more calcium than their refined counterparts, such as white bread.
• Tofu: Tofu is an excellent source of calcium and is particularly suitable for those on a vegan diet or who are lactose intolerant.

It is important to note that the amount of calcium our bodies can actually absorb and use varies from food to food. This is also called bioavailability. Calcium from dairy products is generally more easily absorbed than from spinach.

Source: Harvard Health, 2023

What is calcium deficiency?

Calcium deficiency (hypocalcemia) is a medical condition characterized by abnormally low levels of calcium in the blood. A deficiency of this important mineral can cause a number of health problems.

Causes of calcium deficiency

The three most common causes of hypocalcemia include:

1. Parathyroid hypofunction: This condition is also known as hypoparathyroidism and occurs when the parathyroid glands do not produce enough parathyroid hormone (PTH), which is essential for regulating calcium levels. This can lead to low calcium levels.
2. Vitamin D deficiency: Vitamin D helps the body absorb calcium properly. A lack of vitamin D in the body can lead to low calcium levels in the blood and may be due to certain diseases, medications, or too little sunlight.
3. Kidney failure (renal insufficiency): Hypocalcemia in kidney failure is a result of decreased utilization of vitamin D by the kidneys. Without enough vitamin D, the body absorbs less calcium from food, causing blood calcium levels to drop (National Kidney Foundation, 2023).

In addition, certain medications, some genetic conditions, low magnesium levels (hypomagnesemia), and acute pancreatitis (inflammation of the pancreas) can also cause low calcium levels. Calcium deficiency also commonly occurs after thyroid removal or during mild dehydration (lack of fluid in the body). Early diagnosis and treatment of calcium deficiency is critical to prevent serious complications and unpleasant symptoms.

Source: Mayo Clinic, 2023

Symptoms of calcium deficiency

Since calcium plays a fundamental role in many bodily processes, a deficiency can cause a range of symptoms. In most cases, these symptoms go unnoticed at first because they are often subtle and can be confused with other medical conditions. They can also vary in severity. Here are some of the common symptoms associated with calcium deficiency:

1. Muscle weakness and cramps: Because calcium plays a critical role in muscle contraction and relaxation, a deficiency of this mineral can cause involuntary muscle contractions or cramps. 
2. Numbness and tingling: A calcium deficiency can affect the normal function of nerves, resulting in abnormal sensations such as numbness, tingling, or even burning sensations in the hands, feet, and around the mouth.
3. Bone loss and fractures: since calcium is a major component of our bones, a deficiency can lead to a weakening of the bone structure. This can lead to increased bone loss (osteoporosis) and increase the risk of fractures.
4. Fatigue and lethargy: insufficient calcium levels can lead to general weakness, chronic fatigue, or lethargy as this mineral affects energy production and nerve function.
5. Heart problems: calcium is critical for contraction of the heart muscle and electrical control of the heart. A deficiency can lead to arrhythmias and other heart-related problems. If you experience symptoms such as heart palpitations, chest pain (angina), you should see a doctor immediately. Please note these symptoms may slightly differ between women and men.

Source: Cleveland Clinic, 2023, NIH, 2021

It is important to note that these symptoms can also occur due to other health conditions or nutrient deficiencies. To rule out other possible causes, speak to your healthcare provider. If you have more than one of these symptoms, especially if you are in a risk group for calcium deficiency, they can arrange a calcium test and follow-up care if needed.

Risk groups for calcium deficiency

There are several risk groups that are particularly susceptible to calcium deficiency.

1. Lactose intolerance and milk allergies:People who are lactose intolerant or have a milk allergy may be deficient in calcium due to their limited ability to consume dairy products. This may also apply to people who follow a vegan diet, as many calcium-rich foods are of animal origin.
2. Pregnant and breastfeeding women: Women who are pregnant or breastfeeding need more calcium to meet their baby’s needs and keep their own bones healthy.
3. Older adults:Older people may be at higher risk for calcium deficiency due to inadequate calcium intake, for example, due to changes in eating habits, but also due to poorer calcium absorption. Medications: Medications that interfere with the body’s ability to absorb calcium from food can also cause calcium deficiency.
4. Postmenopausal women: women after menopause are more susceptible to calcium deficiency because their bone mass decreases (due in part to a decrease in estrogen) as they age.
5. Other health conditions:People with certain health conditions, such as chronic kidney disease or malabsorption syndromes that affect the body’s ability to absorb nutrients, are at risk of calcium deficiency.

Source: Beto, 2015

Calcium deficiency and other diseases

Calcium intake has an effect on our overall health, including risk for other diseases. Osteoporosis is a disease that affects the bones, making them weak and brittle. One of the main causes of osteoporosis is a long-term deficiency of calcium, which is necessary to maintain bone health (NIAMS, 2023).

Although further studies are needed to draw firm conclusions, there is also preliminary evidence that adequate calcium intake may reduce the risk of cardiovascular disease and certain cancers. However, excessive calcium consumption is also not optimal- high calcium levels carry an increased risk of prostate cancer and kidney stones (NIH, 2021).

Diagnosing calcium deficiency

Diagnosing calcium deficiency usually occurs in three parts, beginning with a trip to the doctor:

1. Medical history and physical examination: this discussion with the physician includes possible symptoms, dietary habits, and possible risk factors for calcium deficiency.
2. Diagnosis of calcium deficiency: this is done by performing a blood test to determine the level of calcium in the blood.
3. Other tests: this step is helpful to determine possible causes of calcium deficiency or to determine the severity of the deficiency. For example, these may include bone density measurements (to rule out or confirm osteoporosis), kidney function tests (to detect kidney disease that may affect calcium absorption), and vitamin D tests (because vitamin D deficiency can affect calcium absorption).

Source: Cleveland Clinic, 2022

How is calcium deficiency treated?

Treatment of calcium deficiency focuses primarily on increasing calcium intake and addressing possible underlying causes. Treatment may include:

• Treating underlying conditions: If calcium deficiency is due to a specific medical condition, such as kidney disease, it must be treated accordingly. This could include a specific medication, a change in existing medications, or other medical procedures.
• Dietary changes: one of the first steps in treating calcium deficiency is often a change in diet. Eating calcium-rich foods regularly can increase calcium levels in your body.
• Supplements: in some cases, it may be necessary to take calcium supplements to increase calcium levels. This is especially the case when it is difficult for an individual to get enough calcium from food. However, the amount and type of supplements should always be determined by a physician to avoid overdose.
• Vitamin D: Since vitamin D plays a key role in calcium absorption, it is often recommended to also take a vitamin D supplement or spend more time in the sun to increase the body’s vitamin D production.
• Regular checkups: If you have a calcium deficiency, it is important to have regular blood tests to monitor calcium levels and assess the effectiveness of treatment. This can be done in a medical laboratory or at home with using a self-test kit.

Would you like to measure your vitamin D levels in order to support proper calcium absorption and overall health? Homed-IQ’s Vitamin D Test measures the level of vitamin D in your blood in the comfort of your own home. Homed-IQ’s blood testing process is straightforward and involves taking a small blood sample using a specialized kit that is sent to your home. After collecting a blood sample from a finger prick, simply ship the test to one of our certified laboratories for analysis, with the results delivered to you digitally within a few days.

Source: Cleveland Clinic, 2022

Please note that treatment for calcium deficiency should be individualized to the patient and take place under a doctor’s supervision. Although supplements are available without a prescription, they should not be taken before consulting a physician.

Can calcium levels in the body be elevated?

An elevated blood calcium level, medically referred to as hypercalcemia, is as serious a disorder as a calcium deficiency. Some of the most common symptoms include excessive thirst, frequent urination, stomach problems, fatigue, depression, or confusion. Common causes of elevated calcium levels include hyperparathyroidism, certain cancers, and excessive vitamin D intake. Persistently high calcium levels can cause serious health problems, so it is important to check calcium levels regularly and consult a doctor if you are experiencing signs of hypercalcemia (Mayo Clinic, 2023). 

Summary

Calcium is an essential mineral that plays a central role in our bodies. A calcium deficiency can lead to health problems and long-term impacts on bone health. You can keep your calcium levels in balance by eating a balanced diet and consulting your doctor if you believe you have or are at risk of a potential calcium deficiency.

References:

Beto, J. A. (2015). The role of calcium in human aging. Clinical nutrition research, 4(1), 1-8. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4337919/

Calcium and Vitamin D: Important for Bone Health. (2023, May 1). National Institute of Arthritis and Musculoskeletal and Skin Diseases. Retrieved June 27, 2023, from https://www.niams.nih.gov/health-topics/calcium-and-vitamin-d-important-bone-health

Calcium | The Nutrition Source | Harvard T.H. Chan School of Public Health. (n.d.). Harvard T.H. Chan School of Public Health. Retrieved June 26, 2023, from https://www.hsph.harvard.edu/nutritionsource/calcium/

Definitions of Health Terms: Minerals. (2022, March 2). MedlinePlus. Retrieved June 26, 2023, from https://medlineplus.gov/definitions/mineralsdefinitions.html

Fleet, J. C. (2017). The role of vitamin D in the endocrinology controlling calcium homeostasis. Molecular and cellular endocrinology, 453, 36-45. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5529228/

Hypercalcemia – Diagnosis and treatment. (2023, April 14). Mayo Clinic. Retrieved June 26, 2023, from https://www.mayoclinic.org/diseases-conditions/hypercalcemia/diagnosis-treatment/drc-20355528

Hypercalcemia – Symptoms and causes. (2023, April 14). Mayo Clinic. Retrieved June 27, 2023, from https://www.mayoclinic.org/diseases-conditions/hypercalcemia/symptoms-causes/syc-20355523

Kidney Failure Risk Factor: Serum Calcium. (n.d.). National Kidney Foundation. Retrieved June 27, 2023, from https://www.kidney.org/content/kidney-failure-risk-factor-serum-calcium

Vitamins and minerals – Calcium. (n.d.). NHS. Retrieved June 26, 2023, from https://www.nhs.uk/conditions/vitamins-and-minerals/calcium/What Calcium Does and How Much You Need. (2023, June 13). Cleveland Clinic Health Essentials. Retrieved June 26, 2023, from https://health.clevelandclinic.org/calcium/