If someone has osteoporosis and is put on calcium by a medical doctor, I recommend a calcium supplement. Or if someone has low serum calcium in their blood, then yes, I also recommend calcium supplements. I know adequate levels in the blood are essential for muscle contraction and biochemical reactions such as blood clotting.
In the hospital, we infuse a lot of life-saving calcium intravenously for people who have low serum levels. I know that these patients can develop fatal heart arrhythmia and other life- threatening complications if the blood calcium levels are not restored to normal. We even keep IV calcium in our crash carts to bring people back to life.
But for my patients who are healthy, have healthy bones, and want to keep their bones healthy, then no, I do not recommend calcium supplements and here's why:
The more calcium we consume, the less our bodies absorb and the more it will excrete calcium into the urine.1 We cannot force our bodies to do what we want it to do when it comes to strong bones and calcium.
Growing kids absorb about 60% of the calcium in their stomach that is from food sources. Pregnant and nursing women can also absorb up to 60%.1,2 A full-grown adult can absorb about 30% but it decreases with age to about 15-20%.1 An elderly person sitting on the couch, watching TV, popping calcium pills absorbs about 5% to 10%. (No reference, this is just my silly opinion.)
Our calcium absorption, retention, and deposition into the bones is controlled by hormones such as growth hormone, estrogen, testosterone, and of course the master calcium regulator, the parathyroid hormone.
Our bodies are smarter than us. We would turn into a stone calcium statue if our bodies absorbed all the calcium we ingested.
So if someone wants to keep their healthy bones strong, I recommend eating foods high in calcium and doing weight-bearing exercises. Weight-bearing exercises are our safest bet to stimulate the hormones to absorb more calcium and incorporate it into our bones.
However, taking a moderate amount of vitamin D will also increase the amount of calcium our bodies absorb. Instead of 30% maybe we can absorb 35 or 40%.1
The US Task Force also recommends against using calcium and vitamin D supplements to prevent bone fractures. According to MedlinePlus website: “The Task force recommends against daily supplementation with 400 IU or less of vitamin D3 and 1,000 mg or less of calcium for the primary prevention of fractures in noninstitutionalized postmenopausal women.” Click on the linked tab for the PDF download for preventing fractures.
The US Task Force is a group of volunteer medical experts who review the medical literature and come to a consensus of recommendations for the American public. I follow their recommendations closely because I value that consensus. I value that there was a lengthy discussion on the subject by several highly educated, experienced, and altruistic individuals. The last thing I want is a one-person opinion from someone who attended a weekend herbal workshop and has motives to sell me something. Or even worse is an article written by a journalist without formal medical education and experience who is looking for a unique angle on a story to spin out of control in a desperate attempt to get ratings.
If my patients suspect they have osteoporosis or poor bones, then I recommend a bone density test. If they do in fact have osteopenia or osteoporosis, then their doctor will prescribe the appropriate medication to reverse and restore the condition. The powerful drug options are biphosphate, miacalcium, and prolio (Denosumab) to stop bones from break down; estrogen and evista for menapausal women to stimulate calcium absorption and storage through estrogen activity; and fortio (Teriparatide) a powerful anabolic hormone that builds bone like the energizer bunny. It has a 2-year use limit so that bone over growth does not occur. It is the parathyroid hormone.
If a patient tells me a doctor has put them on calcium, then I highly recommend they keep taking it. It is medically necessary. But for people wanting to put themselves on calcium for the sake of keeping their bones strong, I offer a more natural approach such as foods high in calcium and weight-bearing exercises. I also recommend they have their vitamin D levels checked to make sure they are in the normal range.
I NEVER recommend men put themselves on calcium because it has been linked to prostate cancer.3 The risk does not outweigh the benefits, in my opinion.
However, calcium supplementation has also been linked to a reduction of colon cancer.4
Yes you read correctly, calcium can cause and prevent cancer. It has also been shown to both worsen5 and improve/prevent cardiovascular disease.6 I have seen this dichotomy of results several times. It is a pattern that occurs with some, but not all, nutraceuticals. It is my belief that this is occurring because when a nutritional deficiency is restored to normal, miraculous health benefits occur; conversely, when normal levels are elevated even higher with synthetic supplements, good things rarely happen and sometimes bad things happen.
It is my belief that the study outcome results are dependent on the nutritional status of the participants at the start of the study. IF the participant is poorly nourished, they will benefit from the nutraceutical. If they are well nourished, and they take synthetic nutraceutical pills then they do not benefit, and they may have a bad outcome such as cancer or accelerated cardiovascular disease. 7,8,9
The cardiovascular concern with calcium comes from the knowledge that the plaque in the arteries is partially made up of calcium. Are unnaturally high calcium levels in the blood from pills precipitating out of the bloodstream and depositing in the arteries to accelerate atherosclerosis? We know that calcium carbonate supplements cause kidney stones. Is the calcium precipitating out of the urine? Does it precipitate out of the blood?
Calcium also plays a part of the clot-forming cascading system. It’s a concern that high blood levels of calcium are driving that cascading system to form clots in the already narrow passages of atherosclerosis causing strokes and heart attack.10,11,12,13
It is my opinion that we should only be taking calcium pills when our doctors prescribe them. We do not want to inundate our body with calcium unless we have the hormones in place to incorporate the calcium into our bones.
1.) Committee to Review Dietary Reference Intakes for Vitamin D and Calcium, Food and Nutrition Board, Institute of Medicine. Dietary Reference Intakes for Calcium and Vitamin D. Washington, DC: National Academy Press, 2010.
2.) National Institutes of Health. Optimal calcium intake. NIH Consensus Statement: 1994;12:1-31.
3.) Gao X, LaValley MP, Tucker KL. Prospective studies of dairy product and calcium intakes and prostate cancer risk: a meta-analysis. J Natl Cancer Inst. 2005;97:1768-1777.
4.) Weingarten MA, Zalmanovici A, Yaphe J. Dietary calcium supplementation for preventing colorectal cancer and adenomatous polyps. Cochrane Database Syst Rev. 2008 Jan 23;(1):CD003548.
5.) Bostick RM, Kushi LH, Wu Y, Meyer KA, Sellers TA, Folsom AR. Relation of calcium, vitamin D, and dairy food intake to ischemic heart disease mortality among postmenopausal women. Am J Epidemiol. 1999 Jan 15;149(2):151-161.
6.) Michaelsson K, Melhus H, Warensjo Lemming E, Wold A, Byberg L. Long term calcium intake and rates of all cause and cardiovascular mortality: community based prospective longitudinal cohort study. BMJ 2013;12;346:f228.
7.) Bolland MJ, Avenell A, Baron JA, Grey A, MacLennan GS, Gamble GD, Reid IR.Effect of calcium supplements on risk of myocardial infarction and cardiovascular events: meta-analysis. BMJ. 2010 Jul 29;341:c3691.
8.) Bolland MJ, Barber PA, Doughty RN, Mason B, Horne A, Ames R, Gamble GD, Grey A, Reid IR. Vascular events in healthy older women receiving calcium supplementation: randomised controlled trial. BMJ. 2008; 2;336:262-266.
9.) Li K, Kaaks R, Linseisen J, Rohrmann S. Associations of dietary calcium intake and calcium supplementation with myocardial infarction and stroke risk and overall cardiovascular mortality in the Heidelberg cohort of the European Prospective Investigation into Cancer and Nutrition study (EPIC-Heidelberg). Heart. 2012;98:920-925.
10.) Xiao Q, Murphy RA, Houston DK, Harris TB, Chow WH, Park Y. Dietary and Supplemental Calcium Intake and Cardiovascular Disease Mortality: The National Institutes of Health-AARP Diet and Health Study. JAMA Intern Med. 2013 Feb 4:1-8.
11.) Bolland MJ, Grey A, Avenell A, Gamble GD, Reid IR. Calcium supplements with or without vitamin D and risk of cardiovascular events: reanalysis of the Women’s Health Initiative limited access dataset and meta-analysis. BMJ. 2011 Apr 19;342:d2040.
12.) Wang L, Manson JE, Sesso HD. Calcium intake and risk of cardiovascular disease: a review of prospective studies and randomized clinical trials. Am J Cardiovasc Drugs 2012;12:105-16.
13.) Seely S. Is calcium excess in western diet a major cause of arterial disease? Int J Cardiol 1991;33:191-8.