Supplemental Calcium: Pros and Cons

One of the most crucial nutrients for good bone and dental health is calcium. It is widely acknowledged that calcium is necessary for the correct functioning of the heart, muscles, and nerves. Several studies also suggest that calcium and vitamin D may have advantages beyond bone health. In the United States, millions of women take calcium supplements in an effort to strengthen their bones, particularly after menopause when the risk of fractures rises. Additionally, calcium supplements are frequently taken by people with rheumatoid arthritis and other inflammatory forms of the condition.

Most people consume adequate calcium as part of a healthy diet. Those who don’t, however, might need to take calcium supplements. It’s critical for people to understand how much calcium they require as well as the best kinds of supplements to take. 1

The use of calcium supplements is not universal. For instance, calcium supplements should not be taken by persons who have hypercalcemia, a medical disease that results in an excess of calcium in the blood. For certain people, calcium excess or deficiency from food or supplementation could be harmful.

This article briefly discusses the daily requirements for calcium in humans, various calcium supplements, calcium’s role in nutrition, and the negative effects of consuming too little or too much calcium.

Different Calcium Supplement Types

Calcium supplements come in two major forms: citrate and carbonate. Since calcium carbonate is the least expensive, it is a sensible choice. Numerous distinct calcium salts are present in calcium supplements. The amount of calcium found in each salt varies. Calcium carbonate, which contains 40% elemental calcium, calcium citrate, which contains 21% elements calcium, calcium lactate, which contains 13% elemental calcium, and calcium gluconate are the most popular calcium supplements (9 percent elemental calcium).

Additionally, some calcium supplements also contain magnesium or vitamin D. To determine the type and quantity of calcium included in a product, read the product labels carefully and examine the supplement ingredients. If a person has any dietary restrictions or health issues, this information is crucial.

Dosage and management

Age and sex both affect how much calcium is needed daily. The bone mass of the body reaches its peak between the ages of 18 and 25 and then gradually decreases. For adult males, the RDA for calcium is as follows: 1,000 mg for those between the ages of 19 and 70 and 1,200 mg for those over 71. The RDA for calcium for females is 1,000 mg for those under the age of 19 and 1,200 mg for those over the age of 51.

Unless directed otherwise by a physician or nutritionist, people should not take more than 1,200 mg of calcium (in supplement form) each day. Most Americans obtain between 750 mg and 900 mg of calcium per day only from their diet.

It is now understood that calcium absorption greatly benefits from vitamin D (calciferol). Before 1997, the recommended daily allowance (RDA) for calcium and vitamin D was 200 IU (international units) for individuals under 50, 400 IU for those between 51 and 70, and 600 IU for those over 70. Due to decreased vitamin D production in aging skin, the requirements rise with age. Since then, other recommendations have been made, as will be explained below.


Lack of calcium

Hypoparathyroidism, achlorhydria, chronic diarrhea, vitamin D insufficiency, steatorrhea, sprue, pregnancy and lactation, menopause, pancreatitis, renal failure, alkalosis, and hyperphosphatemia are conditions linked to calcium shortage. Hypocalcemia may occasionally develop with the administration of specific medications (such as some diuretics and anticonvulsants), which may call for calcium replacement therapy. 3

Low calcium intake can also occur in people who consume a vegan diet, have lactose intolerance and avoid dairy products, consume a lot of protein or sodium, have osteoporosis, have received long-term corticosteroid treatment, or have certain bowel or digestive diseases like celiac disease or inflammatory bowel disease that impair calcium absorption. Calcium supplements may help people fulfill their calcium needs in certain circumstances. 3

Sources of Calcium

Calcium must be obtained from natural sources or as a supplement in order to support bone growth and maintenance to prevent osteoporosis-related fractures. Dairy products include calcium, as do a number of non-dairy items such cereals, figs, soft-boned fish, and meals that have been fortified with calcium. One might not obtain enough calcium each day even with good food and a balanced diet.
Coral calcium and oyster shell calcium are two more natural sources of calcium. Calcium carbonate in the form of coral calcium is obtained from fossilized coral sources. Chelating is a natural process that the human body goes through to combine calcium with another substance (such as an amino acid) that the body can digest. Additionally, bone grafting and maxillofacial surgery both require coral calcium. 2,4

Calcium and vitamin D: Vitamin D plays a crucial function in the body’s absorption of calcium and the maintenance of bone density. Because of this, some calcium pills also contain vitamin D. There are two types of this vitamin: vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). Compared to the D3 form, the vitamin’s D2 form has a shorter shelf life. 5

Egg yolks and canned salmon with bones are two examples of foods that are known to contain trace quantities of vitamin D. In addition to meals that have been fortified with vitamin D, exposure to sunlight naturally produces vitamin D. The recommended daily allowance (RDA) for vitamin D is 600 IU for people under the age of 70 and for pregnant or nursing women, and 800 IU for people over the age of 71.

The biologically active version of vitamin D known as calcitriol (Rocaltrol) is used to treat and prevent low calcium levels in the blood in patients whose parathyroid glands or kidneys are not working normally.

Calcium and vitamin K2: MK-4 to MK-10 are the names of the many isoforms or analogs of vitamin K2. This vitamin significantly reduces the risk of osteoporosis and the pathologic calcification of the arteries and soft tissues, both of which are well-known effects of aging. Animals and bacteria, especially healthy probiotic bacteria from the gastrointestinal tract, contain vitamin K2. Antibiotics affect the formation of vitamin K2 and obstruct the healthy bacteria’s ability to grow normally. 4,5

The slower-acting vitamin K2 has been acknowledged as being as vital for bone health, despite the fact that vitamin D3 has been known as the bone vitamin since it activates the osteocalcin gene and works quickly on bones. Every 8 to 10 years, healthy, dense bone completely replaces the human skeleton, and these two vitamins are crucial to that process. The daily dosage of vitamin K2 for oral osteoporosis treatment is 45 mg.

Dietary considerations

When choosing a calcium supplement, the following aspects need to be taken into account.

Elemental calcium: The quantity of calcium in a supplement that is actually absorbed by the body is crucial for bone development and other health advantages. Finding out how much calcium is in a serving by reading the label on calcium supplements is beneficial (number of tablets). For instance, 500 mg of elemental calcium is present in 1,250 mg of calcium carbonate (40 percent ).

Supplement Selection: Due to side effects such gas, constipation, and bloating, some people are unable to handle particular calcium supplements. To determine which calcium supplement he or she can tolerate the best, a person may need to test out a few various brands or varieties. Calcium carbonate, which generally causes the most constipation, has the highest calcium content and costs the least amount of money. Although calcium phosphate is more expensive than calcium carbonate, it does not result in gas or constipation. The most readily absorbed form of calcium, calcium citrate, does not require stomach acid for absorption, although it is costly and contains little elemental calcium. Women should consume enough calcium from their diet and through supplements.

There are numerous dose forms for calcium supplements, including chewable pills, capsules, liquids, and powders. Calcium supplements that are chewable or liquid can be used by people who have difficulty swallowing tablets.

Drug Interactions: Calcium supplements may interact with a wide range of prescription drugs, including calcium channel blockers for blood pressure, synthetic thyroid hormones, bisphosphonates, and antibiotics. The best experts to talk to regarding potential drug interactions and advice on calcium supplements are pharmacists.

Calcium must be able to be absorbed by the body in order for it to be functional and bioavailable. In order to enhance absorption, calcium supplements should be given in tiny quantities (500 mg at a time). The type of calcium citrate, which is equally absorbed with or without food and is advised for those with inflammatory bowel disease or low stomach acid (those who are older than 50, taking antacids, or using proton pump inhibitors), is known to be the most effective.

Cost and Quality: According to the Federal Trade Commission, supplement makers must make sure that their products are safe and that any claims they make are accurate. Numerous businesses could have their goods independently examined in accordance with USP (U.S. Pharmacopeia) standards. The USP acronym indicates that a supplement satisfies quality assurance requirements.

Cardiovascular Effects of Calcium Supplementation

Due to the calcification of the arteries and veins, some worries have been expressed regarding the potential negative consequences of high calcium intake on cardiovascular health in the elderly. These effects could be caused by a number of pathophysiological pathways, including those that affect vascular calcification, vascular cell function, and blood coagulation. However, more recent research has not discovered an elevated risk of heart attack or stroke in women taking calcium supplements throughout the course of a 24-year follow-up period.

Some scientists think there may be no net advantages from calcium supplements because they result in slight decreases in fracture risk and small increases in cardiovascular risk. They contend that calcium from food sources may be better to supplements because they appear to have equivalent effects on bone density and are not linked to negative cardiovascular effects. To prospectively examine the impact of calcium or calcium + vitamin D supplementation beyond bone health, more research is needed. Medical professionals are still unsure of how calcium supplements affect women. 8

Calculating Calcium Levels in Coronary Arteries

At older ages, calcium deposits can be seen throughout the body. A coronary calcium scan is often performed to look for calcium deposits in plaque on the inside walls of the heart’s arteries. Scores on a coronary calcium scan can be as high as 400. A calcium score of zero indicates the absence of any discernible plaque, while a score of 400 or more suggests severe coronary constriction and atherosclerotic plaque buildup.

At least 65 years old, arterial wall calcification is prevalent. Women over the age of 50 frequently get breast calcification. Because calcification is constituted of calcium phosphate, identical to that in bone, it may be plainly seen on x-ray pictures.

Coronary calcium, which only occurs in atherosclerotic arteries and is missing from normal vessel walls, plays a role in the development of atherosclerosis. A calcium score that measures the quantity of calcium in the coronary artery walls appears to be a more accurate predictor of cardiovascular disease risk than traditional risk variables.

Getting Balance

Low Calcium Intake Risks Calcium is necessary for strong bones and teeth, as well as for normal muscle and nerve function, as was previously noted. Low calcium levels can lead to the following health issues: Both children and adults may not grow to their full adult height potential, which increases the risk of osteoporosis and hip fractures. The acts of parathyroid hormone, the kidneys, and the intestines maintain normal blood calcium levels. Serum calcium levels in adults should range from 4.5 to 5.5 mEq/L.10

About 40% of the serum calcium is ionized (free), and the remaining 60% is complexed, mostly to albumin. The only calcium that enters cells and is metabolically active is ionized calcium. Different symptoms are brought on by drops in calcium’s ionized (free) portion. Limited calcium levels, a lack of vitamin D or K2, chronic renal failure, hypoparathyroidism, and low calcium absorption are the most frequent causes of hypocalcemia, or low levels of calcium. 10

Risks of High Calcium Intake: Blood calcium levels can rise as a result of numerous factors. High calcium levels can result from underlying illnesses, drug interactions, or excessive supplement use even though the body has a built-in regulating system for calcium intake and maintenance.

A calcium level that is too high can lead to harmful health issues and needs to be treated medically. Although calcium from food is normally safe, too much calcium does not offer further bone protection. In fact, consuming too much calcium through diet and supplements can lead to kidney stones, prostate cancer, constipation, calcium accumulation in blood vessels, and decreased iron and zinc absorption.

It’s possible to raise calcium levels above average by taking calcium supplements and eating foods that have added calcium. Therefore, it is crucial to follow the RDA and not go over the advised dosage. 10


Preventing calcium shortage is the best method to treat it. Risk factor modification is essential, and pharmacists can contribute significantly in this regard. They are qualified to suggest suitable calcium and vitamin D supplements. Women in particular should consume foods and beverages high in calcium and vitamin D, give up smoking, and increase weight-bearing and muscle-strengthening activity if they are at risk of low calcium levels. In order to lower the risk of bone fractures, it’s also crucial to monitor body mass index as one matures.

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