Are Calcium Supplements Dangerous?

It is a common perception that calcium is the primary ingredient needed for a healthy bone and only calcium is necessary for bone health and because of this perception many people consume heavy doses of calcium supplements without even a physician’s prescription. However, the actual case is just the opposite as calcium is one of those ingredients that are necessary for bone health, and taking too much calcium can cause multiple diseases as it has a higher tendency of deposition in blood vessels and stones [1].

It must be admitted that our ancestors were more educated than this generation as they were used to consuming calcium and magnesium in the ratio of 1:1 whereas American food now is comprised of a 10:1 ratio of calcium and magnesium. It means that Americans intake 10 units of calcium and only 1 unit of magnesium representing that only 1 unit of calcium is absorbed in the blood to contribute to bone health because it needs 1 unit of magnesium as well to complete the process of calcium absorption. Not only magnesium but there are various other nutrients as well that contribute to calcium absorption for bone health [2].

Bone Formation

The formation of a human bone is based on different nutrients, hormones, and assistive ingredients that work synergistically to make bone healthy. The main nutrients include protein, calcium, vitamin D, magnesium, vitamin K, phosphorous, and potassium whereas the hormones that play an important role include the PTH, TSH, Growth hormone, and estrogens. This represents that people with lower levels of protein (collagen), vitamin D and K, magnesium and phosphorous, tend to have weaker bones no matter their calcium level is adequate. Similarly, a recent study showed that women with imbalanced estrogen levels experience arthritis, osteoporosis, osteopenia, and other bone diseases. However, the assistive ingredients are also essential to complete the process of calcium absorption and maintaining the bone structure and function which include vitamin K, vitamin C, B vitamins, zinc, iron, boron, manganese, and copper. Therefore, without a balanced intake of all these nutrients, calcium supplements can be harmful to health [2].

There are five primary reasons due to which excessive calcium supplements can be dangerous for health

  1. Bone Health

The widespread perception of using calcium supplements is that it prevents bone fractures however, the reality does not fit this perception because calcium does not prevent hip fractures which has the highest prevalence rate among all types of bone fractures. This is because calcium alone cannot restore bone health and prevent fractures but it requires vitamin D, vitamin K and magnesium to be absorbed into the blood to provide strength to the bones and when these nutrients are not available in the body, the high level of calcium is just wasted [2, 3].

  1. Heart Diseases

Calcium can significantly increase the risk of cardiovascular diseases such as myocardial infarction because a higher level of calcium can lead to ectopic calcification in the heart muscles. Calcification is the term that refers to the process of calcium deposition in the tissues causing them to be tightened and hardened [2, 3]. On the other hand, Capozzi et al. suggested that calcium is the primary cause of heart attacks since it is the main ingredient that contributes to atherosclerosis. The process of atherosclerosis can be defined as the thickening of the blood vessels due to the deposition of plaque [2]. Therefore, as Wei and Inan described that plaque is the key component that clogs the blood vessels and leads to a heart attack. The composition of plaque is based on calcium, cholesterol, cellular waste products, fibrin, and fatty substances. However, it should be considered that 30% of plaque is comprised of calcium that makes it hard to be dissolved and it leads to the incidence of heart attacks and other heart diseases [3].

  1. Stroke

A large number of studies have proved that excessive calcium can be a trigger to ischemic stroke because excessive calcium results in calcification in the nerves blocking the nervous supply to the brain and other parts of the body. Therefore, a high dose of calcium supplements increases the risk of ischemic stroke by 19% as compared to the people who do not consume a high dose of calcium supplements [4].

  1. Kidney Stone

As suggested by Mitema, Sangiah, and Martin, a higher level of calcium does not contribute to bone health but it deposits somewhere in the body, so it can be deposited in the form of kidney stones. About 80-90% of a kidney stone is composed of calcium oxalate and calcium phosphate representing that an excess amount of calcium helps in the formation of kidney stones [5].

  1. Macular Degeneration

The macula is a part of the retina that is responsible for clearing the vision and sending visionary signals to the brain. Macular degeneration is caused by the leakage of fluid, calcium, or blood in the macula making the central vision blurred and unclear. It is estimated that people older than 67 years are at greater risk of macular degeneration due to the calcium leakage into the macula. And if the older people consume a high dosage of calcium, they are 4 times greater at risk of developing macular degeneration as compared to the people who do not use high dose calcium supplements [6].

What to Do to for Bone Health

It must be clear that only calcium supplements intake or excessive calcium increases the risk of heart diseases, stroke, kidney stones, and macular degeneration, therefore it is necessary to maintain the balance of essential nutrients in the body. A healthy body requires 13 vitamins, 16 minerals, more than 50 hormones, and more than 40 neurotransmitters to function properly and maintain bone health. Therefore, it is needed to take care of all the essential nutrients that contribute to calcium absorption and bone health [6, 7].

For this reason, lab diagnostics are important to figure out which nutrient is deficient and which is adequate so that respective supplements can be used. Besides this, K2 and D3 complete supplements by ASTR can also contribute significantly to bone health as these components help in calcium absorption and bone health [2, 7].


  1. Li K, Wang XF, Li DY, Chen YC, Zhao LJ, Liu XG, Guo YF, Shen J, Lin X, Deng J, Zhou R. The good, the bad, and the ugly of calcium supplementation: a review of calcium intake on human health. Clinical interventions in aging. 2018;13:2443.
  2. Capozzi A, Scambia G, Lello S. Calcium, vitamin D, vitamin K2, and magnesium supplementation and skeletal health. Maturitas. 2020 Oct 1;140:55-63.
  3. Wei H, Inan S. Dual effects of neuroprotection and neurotoxicity by general anesthetics: role of intracellular calcium homeostasis. Progress in Neuro-Psychopharmacology and Biological Psychiatry. 2013 Dec 2;47:156-61.
  4. Tebben PJ, Singh RJ, Kumar R. Vitamin D-mediated hypercalcemia: mechanisms, diagnosis, and treatment. Endocrine reviews. 2016 Oct 1;37(5):521-47.
  5. Mitema ES, Sangiah S, Martin T. Effects of some calcium modulators on monensin toxicity. Veterinary and human toxicology. 1988 Oct 1;30(5):409-13.
  6. Hautmann R, Hering FJ, Lutzeyer W. Calcium oxalate stone disease: effects and side effects of cellulose phosphate and succinate in long-term treatment of absorptive hypercalciuria or hyperoxaluria. The Journal of urology. 1978 Dec 1;120(6):712-5.
  7. Sasaki K, Toshiyuki K, Guo B, Ideta K, Hayashi Y, Hirajima T, Miyawaki J. Calcination effect of borate-bearing hydroxyapatite on the mobility of borate. Journal of hazardous materials. 2018 Feb 15;344:90-7.