Calcium Supplement Uses, Benefits, Dosages & Side Effects

Calcium (Ca) is the most prevalent mineral in the human body. Most people know that calcium is important for bone and teeth health, but many do not know that it has many other functions in the body as well.

Calcium is involved in a number of metabolic and physiological processes, like facilitating proper function of the heart and other muscle, as well as facilitating nerve signalling.

Calcium is an essential dietary nutrient, and failure to get enough of it can lead to serious deficiency symptoms. You can get calcium from numerous food sources, some medications, and from dietary supplements. [1][2]

This article will review the ways that calcium works inside the body, why it important for health, daily dosage recommendations, natural food sources, and possible side effects and drug interactions.

Calcium

Essential Mineral

Bone Health

Immune Function

Muscle Function

How It Works:

• Helps build strong bones
• Involved in neuromuscular function
• Helps maintain a healthy immune system

Dosage:

Between 1000 - 2500 mg per day

Safety:

Rated Likely Safe

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View User Ratings* ❯

Why do people use Calcium Supplements?

Calcium (Ca) is a metallic element with atomic number 20. It a basic constituent of most living organisms and it makes up about 3% of the earth’s crust.

The Natural Medicines Comprehensive Database (NMCD) states that calcium supplements are used for various purposes. Some uses include: [3]

• Seizures associated with sudden declines in blood levels of calcium;
• Rectal epithelial hyperproliferation following intestinal bypass;
• Leg cramps and depression associated with pregnancy;
• Latent tetany (involuntary muscle contractions);
• Hypocalcemia (low calcium in the blood);
• Osteoporosis (soft, porous bones);

Calcium dietary supplements are also used orally for diabetes, metabolic syndrome, PMS (premenstrual syndrome), hypoparathyroidism, pre-eclampsia and hypertension.

Oral calcium supplements are also used for diarrhea, reducing elevated lead/fluorine levels, and reducing the risks for developing cardiovascular disease, cancer and stroke.

Calcium is also used orally for lowering LDL-C (low density lipoprotein cholesterol), Lyme disease, retaining teeth in the elderly, weight loss – and to increase survival rates in heart attack patients. [3]

There are various other oral, topical and intravenous uses for calcium-based supplements and medicines. Most uses for calcium have not been substantiated clinically.

How does Calcium Work inside the Body?

About 99% of the body’s total calcium supply is stored inside bone and tooth tissue.

The remaining 1% is found in the blood, extracellular fluid and tissues and cells throughout the body.

When the body needs calcium for metabolic purposes, it “borrows” it from the bones. [1]

The National Institutes of Health (NIH) reports that “Serum calcium is very tightly regulated and does not fluctuate with changes in dietary intakes; the body uses bone tissue as a reservoir for, and source of calcium, to maintain constant concentrations of calcium in blood, muscle, and intercellular fluids.”. [2]

Calcium plays many important roles in the body, including: [1, 2]

• Maintaining proper blood pressure levels;
• Modulating blood clotting;
• Facilitating neuronal communication in the central nervous system;

NIH reports that calcium is also needed for neuronal transmission, secreting hormones, intracellular signaling, muscle contraction, vascular (blood vessel) contraction, and vasodilation (blood vessel expansion). [1]

Calcium is also associated with helping to reduce tenderness, bloating and pain commonly experienced in women with PMS (premenstrual syndrome).

This mineral has also been researched for its ability to help regulate mood swings and for anti-cancer effects in the gastrointestinal tract.

Calcium in Bones and Teeth

Less than 1% of the body’s total calcium stores are needed to facilitate its many critical metabolic functions. The remainder is used to build healthy bones and teeth. [1]

Stored calcium in bone and teeth tissue supports their structure and facilitates their functions. Bone tissue is constantly being replaced in a process called remodeling.

In this process, calcium resorption (breakdown) and deposition (formation) occur continuously in the formation of new bone cells. [1]

NIH states that the balance between deposition and resorption changes as we age. In young people, new bone formation exceeds resorption.

In early and middle adulthood, the processes are about equal in occurrence. And in older people, breakdown exceeds formation. This is particularly true in postmenopausal women. [1]

When bone breakdown exceeds formation for too long, a condition called osteoporosis can develop. Osteoporosis is marked by soft, porous bones. [1]

NMCD states that calcium in bone tissue is primarily in the form of hydroxyapatite.

Women with low estrogen levels may experience reduced calcium absorption and retention. This may lead to an increase in bone turnover, and a loss of bone mass. [3]

Calcium levels in the body can be decreased via defecation, urination and perspiration. [3]

Benefits of Calcium Supplements

In people who have a calcium deficiency, a number of physiological processes can be impaired.

Aside from the functions listed above, calcium is also critical inside the body for maintaining: [3]

• Numerous enzymatic reactions;
• Cell membrane permeability;
• Proper kidney function;
• Capillary permeability;
• Blood coagulation;

Calcium is also important for uptake and binding of amino acids, absorption of vitamin B12 (cyanocobalamin), gastric secretion and hormone storage.

NMCD reports various pharmacological effects associated with calcium in research. Following are brief descriptions of each:

Antacid effects:

Many OTC and prescription antacids contain calcium. The form of this mineral in these medications is calcium carbonate. It works by reacting chemically with hydrochloric acid inside the stomach.

Calcium carbonate is known to be the most potent antacid by weight. Sodium bicarbonate (baking soda) in the next strongest. [3]

Anticancer effects:

Researchers are interested in calcium as a potential anticancer agent. Some preliminary evidence suggests that it might have an antiproliferative effect on colorectal cancer cells; possibly slowing down their abilities to rapidly replicate and progress into tumors.

Oral doses of calcium seem to reverse the hyperproliferation of rectal epithelial cells in intestinal bypass patients. This may occur due to inhibition of excessive output of certain lipids, and bile acids. [3]

Antidiabetes effects:

Some evidence from epidemiological research (population studies) suggests that increased calcium intake is associated with a lower risk for developing type 2 diabetes mellitus.

This seems to be true weather calcium in increased on its own or in combination with vitamin D.

Although mechanisms are unclear, calcium also seems to increase sensitivity to insulin in those without diabetes. [3]

Antihypertensive effects:

Calcium is important for maintaining healthy blood pressure levels. Preliminary evidence suggests that not getting enough calcium in the diet raises the risks for not only hypertension (high blood pressure), but also for cardiovascular disease and stroke.

Although it is not yet clear, researchers think that calcium might reduce blood pressure by upregulating excretion of sodium from the kidneys. In animals, calcium seems to inhibit salt-sensitive-hypertension. [3]

BMD (bone mineral density) effects:

Clinical research shows that calcium seems to suppress certain biochemical markers of bone tissue breakdown (resorption). If so, it might help to reverse, or at least slow down the onset of osteoporosis and/or other bone and joint disorders. [3]

Cholesterol effects:

Calcium may be able to help lower high serum cholesterol levels. It seems to do so by forming insoluble complexes with fatty acids like cholesterol and triglycerides inside the intestinal tract.

When bound into these complex molecules, the fatty acids are excreted in fecal matter without being absorbed into the bloodstream.

Research continues to explore how calcium might help to balance overall blood-lipid levels, and possibly decrease risk factors for cardiovascular disease. [3]

Premenstrual effects:

During the premenstrual period before menstruation begins, women may have decreased calcium levels. This is due to variations in calcium absorption and metabolism via the effects of estrogen.

Researchers believe that low calcium levels may contribute to mood swings, and/or certain other symptoms of PMS. [3]

Kidney effects:

Calcium is able to bind with phosphate inside the intestines. In doing so, phosphate absorption is prevented.

This reduces the risk for hyperphosphatemia (high phosphates) commonly associated with renal (kidney) failure. Both calcium acetate and calcium carbonate are used for preventing this condition.

Calcium citrate is not recommended for preventing hyperphosphatemia because it is known to increase the absorption of aluminum.

Those with hypophosphatemia (low phosphates in the blood) have increased calcium absorption in the gut, and higher levels of calcium in the blood.

Both of these factors can slow down the formation of new bone tissue, and possibly increase the risk for developing calcium stone formations inside the kidneys. [3]

Weight loss effects:

Calcium seems to regulate obesity related to dietary intake by slowing down lipogenesis (fatty acid synthesis), speeding up lipolysis (fatty acid breakdown), and promoting fat loss.

Researchers think these effects might be caused by suppression of a vitamin D analogue called calcitriol, which is known to lower levels of intracellular calcium in adipose (fat) tissue.

Chronic reduction of intracellular calcium in fat cells decreases expression of lipogenic genes, and increases lipolysis. This can lead to a reduction in overall obesity.

Increasing calcium intake can possibly result in lower body weight, mainly due to decreased fat mass.

According to NMCD, “Calcium seems to repartition dietary energy from adipose tissue to lean body mass.” [3]

Calcium Health Benefits

NMCD rates effectiveness of herbs, nutrients and supplements in specific health conditions.

Depending on available clinical evidence, each substance can be rated Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, Ineffective – or Insufficient Reliable Evidence to Rate.

NMCD rates calcium as Effective for: [3]

• Hyperkalemia (high potassium levels);
• Hypocalcemia (low calcium levels);
• Dyspepsia (indigestion);
• Renal (kidney) failure;

Calcium is rated Likely Effective for improving: [3]

• Corticosteroid-induced osteoporosis;
• PMS (premenstrual syndrome);
• Hyperparathyroidism;
• Osteoporosis;

Calcium is Possibly Effective for: [3]

• Fluorosis (excessive fluorine compounds);
• Hypercholesterolemia (high cholesterol);
• Hypertension (high blood pressure);
• Fetal bone mineralization;
• Colorectal cancer;
• Tooth retention;
• Pre-eclampsia;
• Weight loss;

Calcium is Possibly Ineffective for: [3]

• Myocardial infarction (heart attack);
• Cardiovascular disease;
• Breast cancer;

Calcium is rated Ineffective for treating cardiac arrest.

All other therapeutic uses for calcium are currently considered to have Insufficient Reliable Evidence to Rate. [3]

Calcium Deficiency

The medical term for calcium deficiency is hypocalcaemia. Symptoms can range from mild to severe.

Mild hypocalcaemia symptoms can include tingling or numbness in fingers, poor appetite, cramping muscles and lethargy. [1]

More serious hypocalcaemia symptoms can include delayed infant development, skeletal malformations, chronic confusion and dermatitis. [1]

Hypocalcaemia is associated with a condition called rickets that is marked by imperfect bone tissue calcification, soft bones and bowed legs. [1]

Calcium Excess

The medical term for having too much calcium in the blood is hypercalcemia. Some possible symptoms include: [1]

• Hypercalciuria (excessive urinary calcium);
• Vascular and soft tissue calcification;
• Decreased iron and zinc absorption;
• Nephrolithiasis (kidney stones);
• Renal insufficiency;
• Constipation;

Some evidence associates hypercalcemia with increased risk for prostate cancer, but researchers are not yet sure of this. Other research associates high calcium intake from supplements with an increased risk for cardiovascular disease (more below).

Calcium RDA (Recommended Dietary Allowance):

The Mayo Clinic states that the best amount of calcium for an individual to take depends on factors like gender, age, diet and health history.

The following is the recommended daily allowances for calcium intake in adults: [4]

• 1000 mg/day for men between 19 and 70 years of age;
• 1200 mg/day for men over 70;
• 1000 mg/day for women between 19 and 50;
• 1200 mg/day for women over 50;

NIH reports that getting too much calcium from dietary sources is rare. However, using calcium supplements at high doses can increase the risk of hypercalcemia and its related symptoms. [1]

Calcium-rich Foods

Calcium is found in many food sources, making it easy for most people to get adequate amounts from the diets.

Some of the best foods for increasing intake include: dark green leafy vegetables, dried beans and legumes, dairy products, soft-boned fish like sardines, and fortified cereals. [5]

Harvard University asserts that it is always best to get the nutrients you need from fresh, organic foods, rather than getting them from supplements. [5]

NMCD states that calcium sourced from dairy products seems to regulate obesity factors more than elemental calcium supplements. This means that there might be other constituents in dairy foods that help to modulate fat tissue.

Calcium Supplements

Because calcium is very widely available for most people in the foods they eat, taking supplements is not generally recommended for healthy people. [6]

Nutrition Facts states that calcium supplements can increase the risks of developing conditions like glaucoma, kidney stones and hypocalcemia.

That is because soluble oxalates can bind to calcium inside the body and form insoluble calcium oxalate. When calcium oxalate accumulates in the body, it can form stones in the kidneys. [6]

Long-term vegans and other raw food enthusiasts seem to have the same bone concentrations of calcium, and most other minerals, as omnivores with similar age, height weight and exercise levels. This seems true even though the omnivorous diet may provide twice the calcium of a vegan diet. [6]

Increased consumption of fiber and phytates seems to improve bone-mineral density. [3]

NMCD reports that there are currently more than twelve thousand (12000) different dietary supplement products that contain calcium. If you purchase a calcium supplement, make sure it is manufactured from organic and non-GMO sources.

You should seek medical advice before beginning to use a calcium supplement. In most cases, calcium supplementation is not recommended, or necessary, for healthy individuals.

However, it may be recommended for individuals who have a family history of osteoporosis. In particular, women who have mothers with osteoporosis may be advised to use a dietary supplement.

Calcium Side Effects

NMCD states that oral calcium supplements can cause constipation, diarrhea, belching, flatulence, stomach upset and other gastrointestinal side effects. [3]

Excessive amounts of calcium carbonate (more than 20 g/day) can cause nephrocalcinosis (high kidney calcium), milk-alkali syndrome, renal insufficiency and/or hypercalcemia. [3]

Those who already have impaired kidney function can develop milk-alkali syndrome and hypercalcemia with calcium carbonate doses as low as 4 g/day. [3]

Ask your doctor if you should take a calcium supplement; and if so, what the safest dose, and best type, is for you.

Calcium Interactions

NIH states that calcium supplementation can interact with various types of medicine.

If you use any of the following medications routinely, then you should ask your healthcare provider about the safety of using this supplement. [1]

• Tiludronate disodium used for Paget’s disease;
• Fluoroquinolone and tetracycline antibiotics;
• Bisphosphonates used for osteoarthritis;
• Aluminum and magnesium antacids;
• Mineral oil and stimulant laxatives;
• Glucocorticoids like prednisone;
• Anticonvulsants like phenytoin;
• Levothyroxine (Synthroid);
• Thiazide diuretics;

If you use any type of prescription medications, or have any serious health condition, then it is best to discuss using a calcium supplement with your healthcare provider before starting to take this product.

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