Calcium: Benefits, Deficiency, Sources and More (2026)
This article discusses the benefits of calcium, the risk factors and symptoms of calcium deficiency, and calcium-rich foods to include in your diet. As a bonus, we list our favorite calcium supplement products for those of you who want extra help maintaining an optimal daily calcium intake.
Table of Contents
Calcium is the most abundant mineral in the human body. The vast majority of it (99 percent) is stored in the bones and teeth, while the remaining 1 percent resides in the blood and other tissues.
According to the National Institutes of Health (NIH), many people living in the United States get less than the recommended amount of calcium from their diet. Calcium supplements can help make up the difference, but also come with health risk concerns and potential side effects (more about this below). Luckily, there are many calcium-rich food sources that can help you achieve an adequate calcium intake.
While calcium is most commonly associated with bone health, it is also vital to healthy brain, heart and muscle function. Consequently, an inadequate calcium intake can lead to a variety of health issues as well as increase the risk of osteoporosis. Moreover, various health conditions can cause a calcium deficiency in the blood, such as vitamin D deficiency and low levels of parathyroid hormone (PTH).
Author’s Note: For the purpose of this article, ‘calcium deficiency’ is used interchangeably with ‘calcium inadequacy’, but is differentiated from ‘calcium deficiency disease’ (hypocalcemia).
This content is meant to be informative, but should not be taken as medical advice. It is not intended for use as diagnosis, prevention or treatment of health problems. Always speak with your healthcare provider before starting any new supplement or exercise regimen.
What Is Calcium?
Calcium is a mineral essential to human health. It plays a key role in bone mineralization and is required for normal growth, development and bone strength. Additionally, it has a role in numerous biological functions, such as nerve impulse transmission, metabolism, and muscle contraction.
The human body cannot make calcium on its own, so we must get it from food sources or dietary supplements. Dairy products like milk and cheese are popular dietary sources of calcium, but it is also found in dark leafy green vegetables, poultry, fish and fruits. If you are lactose intolerant or allergic to dairy, rest assured that many good sources of calcium are non-dairy.
Benefits of Calcium
Calcium is vital to the body’s structural integrity and healthy functioning. An adequate intake of calcium benefits the health of bones, teeth, brain, heart and muscle function. Calcium even helps to promote hair growth and prevent hair loss.
Calcium and Bones
The effects of calcium on bone development and maintenance are well understood. It is critically important to maintain an adequate level of calcium throughout your lifetime because bone tissue is in a constant state of remodeling. In other words, bone is constantly being broken down (by osteoclasts) and rebuilt (by osteoblasts) as we grow and age.
During adolescence, calcium intake heavily influences skeletal calcium retention and thus, affects peak bone mass achieved in early adulthood. When children don’t get enough calcium, growth is stunted and they fail to reach their full height potential. As we mature past the age of 50, bone density loss becomes a normal part of the aging process, but maintaining an adequate calcium intake can slow it down.
While calcium is the most abundant mineral in our bones, it isn’t the only one. Within our bones, calcium combines with other compounds to form calcium hydroxyapatite—a highly organized crystal of calcium and phosphorus that provides the hardness of bone. Additionally, you’ll find sodium, magnesium, fluoride, potassium and strontium within the bone matrix.
Calcium and Teeth
Calcium is necessary for a picture-perfect smile, as it plays a key role in the formation and maintenance of healthy teeth and gums. Calcium works in conjunction with other minerals like fluoride and phosphorus to help build strong teeth. Calcium also protects and strengthens the enamel (surface) of the teeth, which helps prevent tooth decay. In addition, the calcium in our saliva is needed to drive the remineralization of teeth and repair damage caused by bacteria, sugar and ultimately acid.
A low calcium intake increases your risk of dental problems, such as irritated gums and brittle teeth. Moreover, a calcium deficiency can lead to periodontal disease.
Calcium and the Brain
In the brain, calcium acts in its free form as a calcium ion (Ca2+) and regulates several neuronal functions. It plays a key role in neurotransmitter synthesis and release, neuronal excitability and cell-to-cell communication. Moreover, calcium is fundamental to gene expression, synaptic plasticity, learning and memory formation.
Emerging evidence indicates that calcium homeostasis is not only critical for cell physiology and health, but also plays a key role in the pathology of neurodegenerative diseases. When calcium homeostasis is deregulated, it can lead to the death of brain cells and contribute to the pathogenesis of various brain diseases, such as Alzheimer’s, Parkinson’s and Huntington’s diseases.
Moreover, a 2021 study published in Science Advances found that calcium helps direct blood flow in the brain. It does so by mediating the dilation of brain capillaries (tiny vessels) in order to encourage blood flow to active areas of the brain.
Alongside calcium, natural herbal supplements such as gingko biloba, L-theanine, and ashwagandha have also been studied for their ability to support brain health, promote relaxation and reduce stress.
Calcium and the Cardiovascular System
Calcium plays a major role in the electrical activity and pumping function of the heart. Every time the heart beats, calcium ions flood into the heart muscle cells and contribute to the electrical signal that coordinates the heart’s function. Ionized calcium also binds to protein complexes to help cardiac cells contract (squeeze together), which causes the heart to pump blood.
Dysregulation of calcium can impair the pumping function or relaxation of the heart and lead to heart rhythm disorders and other heart diseases.
Calcium is also important to the vascular system (veins and arteries). It promotes the relaxation of smooth muscle around blood vessels and helps to control blood pressure. Findings from numerous studies suggest a link between a low calcium intake and high blood pressure.
Additionally, calcium is one of the many chemicals (coagulation factors) that play a role in blood clotting.
Calcium and Muscle
Calcium is involved in muscle contraction. When the brain sends a signal to the muscles to move (via nerves) calcium flows into the target muscle tissue. From there, calcium interacts with cellular protein machinery and causes the muscle tissue to contract. When calcium is pumped back out of the muscle tissue, the muscle relaxes.
Signs of Calcium Deficiency
A calcium deficiency can manifest in a number of ways. Signs and symptoms of a calcium deficiency include (but aren’t limited to):
- Muscular cramping, muscle weakness and muscle spasms
- Fatigue
- Lightheadedness, dizziness
- Brain fog (lack of focus, forgetfulness and confusion)
- Poor dental health
- Sensation of pins and needles
- Numbness and tingling in the hands and feet
- Seizures
- Kidney stones
- Dry scaly skin, brittle nails and coarse hair
Note: The above symptoms are typically associated with calcium deficiency disease (hypocalcemia), which is characterized by low calcium levels in the blood. It is very possible to have an inadequate daily intake of calcium without experiencing any of these symptoms.
Who is at Risk of Calcium Deficiency?
The risk factors for calcium deficiency can be broadly characterized as lifestyle-, age- and disease-related.
Lifestyle-related risk factors for calcium deficiency:
- Veganism
- Heavy alcohol use
- Heavy consumption of soda and caffeine
- Heavy consumption of protein and sodium
- Overconsumption of magnesium
- Abuse of drugs
- Long-term use of laxatives
When we sweat, urinate and defecate, calcium is excreted in the process. Foods and activities that encourage these functions may decrease the levels of calcium in the body.
Age-related risk factors for calcium deficiency:
- Over the age of 70
- Postmenopausal woman
In general, middle-aged women are at greater risk for osteoporosis and calcium deficiency than their male counterparts. During menopause, estrogen levels decrease. Estrogen helps increase calcium absorption and retain the minerals in bones. With less estrogen, calcium function suffers and bone loss accelerates. Consequently, many women experience muscle stiffness and joint pain during menopause.
Disease-related risk factors for calcium deficiency and/or hypocalcemia:
- Digestive diseases, such as irritable bowel disease (IBD) and crohn’s disease
- Chronic inflammatory and autoimmune diseases, such as celiac disease
- Vitamin D deficiency
- Low parathyroid hormone levels (hypoparathyroidism)
- Thyroidectomy (removal of the thyroid gland)
- Phosphate deficiency
- Some cancers
- Kidney failure
- Pancreatitis
- Amenorrhea
- Eating disorders, such as anorexia and bulimia
- Lactose intolerance and dairy allergy
- Certain genetic disorders
Additionally, prolonged use of certain medications (e.g. chemotherapy drugs and corticosteroids) can cause hypocalcemia.
The Recommended Daily Intake of Calcium
According to the NIH, the daily recommended dietary allowances (RDAs) for calcium are as follows:
|
Age |
Male |
Female |
Pregnant |
Lactating |
|
0-6 months* |
200 mg |
200 mg |
||
|
7-12 months* |
260 mg |
260 mg |
||
|
1-3 years |
700 mg |
700 mg |
||
|
4-8 years |
1,000 mg |
1,000 mg |
||
|
9-13 years |
1,300 mg |
1,300 mg |
||
|
14-18 years |
1,300 mg |
1,300 mg |
1,300 mg |
1,300 mg |
|
19-50 years |
1,000 mg |
1,000 mg |
1,000 mg |
1,000 mg |
|
51-70 years |
1,000 mg |
1,200 mg |
||
|
>70+ years |
1,2000 mg |
1,200 mg |
* Adequate Intake (AI)
Sources of Calcium
While dairy products such as milk and cheese are the most well-known sources of calcium, this essential mineral is found in several other food groups as well. Some of the most calcium-rich foods are:
- Dairy milk (cow, sheep, goat)
- Soy milk, rice milk, almond milk
- Cheese
- Yogurt
- Leafy vegetables (spinach, collard greens, bok choy)
- Fish (sardines, salmon)
- Poultry
- Fruits (oranges, kiwifruit, mulberries, prickly pears)
- Juices (calcium-fortified orange juice)
- Almonds
- Calcium-fortified cereals
A Caveat to Plant-based Calcium Food Sources
It is important to note that plant-based food sources of calcium typically contain so-called “anti-nutrients” that decrease calcium’s bioavailability. For example, dark leafy green vegetables typically contain oxalates. Oxalates bind to calcium and decrease its bioavailability. While spinach, for example, is high in calcium, it is also high in oxalates. As a result, spinach has a calcium bioavailability of 5 percent. This means if you eat 100 milligrams-worth of calcium from spinach, only 5 milligrams of calcium will be absorbed by the body.
Types of Calcium
Elemental calcium is a pure form of the mineral, but there are other natural forms of calcium where calcium is combined with other compounds. Common forms of calcium you’ll find in calcium supplements include:
- Calcium Bis-glycinate (20 percent elemental calcium)
- Calcium citrate (21 percent elemental calcium)
- Calcium carbonate (40 percent elemental calcium)
- Calcium lactate (13 percent elemental calcium)
- Calcium gluconate (9 percent elemental calcium)
Different types of calcium have varying solubility rates. Their absorption by the body is affected by various factors, such as stomach acid levels. Calcium Bis-glycinate and calcium citrate are two of the most bioavailable forms of calcium. If you are deciding between different calcium supplements, products with calcium in the form of calcium Bis-glycinate and calcium citrate may be worth spending a few extra bucks on.
Who Should Consider Calcium Supplements?
Calcium supplements can help fill the gaps of a low-calcium diet. They may also be useful to individuals with a heightened risk of calcium deficiency or calcium deficiency disease (hypocalcemia). People who should consider calcium supplements includes:
- Vegans
- Individuals with osteoporosis
- Individuals with digestive disorders that limit calcium absorption
- Individuals who have had gastric bypass surgery
- Individuals who receive long-term treatment with corticosteroids
- Elderly men and women (70+ years of age)
- Individuals with a confirmed diagnosis of calcium deficiency disease (hypocalcemia)
Precautions for Calcium Supplements
Bear in mind that calcium supplements come with potential side effects. The side effects of calcium supplements include bloating, gas and constipation.
Additionally, some studies have linked the use of calcium supplements to an increased risk of heart attack. Further research is needed to fully elucidate the relationship between calcium supplements and the risk of cardiovascular disease (CVD).
Final Thoughts
Calcium helps build and maintain strong bones and teeth. It is also vital to muscle movement, brain function and heart health. Many Americans don’t get enough calcium in their diet, and that raises their risk of bone loss, osteoporosis and other health issues.
While there are many whole-food sources of calcium, a calcium supplement may be beneficial to individuals at increased risk for calcium deficiency, such as vegans, the elderly, postmenopausal women and individuals who are lactose intolerant or have a digestive disease. Additionally, healthcare providers commonly recommend calcium supplements to patients with calcium deficiency disease (hypocalcemia).
Too little calcium can cause problems, but so can too much calcium (hypercalcemia). It is important to monitor your dietary calcium intake while taking calcium supplements to avoid exceeding the tolerable upper limit for calcium.
If you experience any of the aforementioned calcium deficiency symptoms, consult a qualified health professional for additional guidance before purchasing a calcium supplement.