By: Caleb Tang
Calcium is an essential mineral and contributor to bone health that helps keep bones strong. In fact, 99% of the body’s calcium is found in bon
e.1 The human body is continually removing calcium from bone so that it can be used to aid in blood clots, muscle movement, and nerve messaging. Dietary calcium actually replenishes these losses and prevents bones from becoming weak. So why wouldn’t increasing the amount of calcium intake positively affect bone health? Imagine that your car is low on gas. Wouldn’t it obviously make sense to go to the nearest gas station and fill up your tank? In the case of bone health, the answer is not that cut and dry. Yes, calcium is an important factor, but increasing intake alone will not directly improve bone health.7
Just three weeks ago, the New York Times published an article titled, “Calcium Doesn’t Improve Bone Density, Analysis Finds”. This surprising claim was made by Nicholas Bakalar of the New York Times. He based his claim on two articles published by the British Medical Journal (BMJ) just this summer. The results from articles review made a bold claim that completely defies common household knowledge. Aside from the fact that the two BMJ articles came to the same conclusion, the two were eerily related. Both were published on the same day (September 29, 2015) and both were associated with the University of Auckland and the University of Otago in New Zealand.
It seems illogical that increasing consumption of a crucial mineral for bone strength would not actually improve bone strength. The apparent paradox lies within biology and culture.9 It is important to realize that one simple dietary change will not affect bone strength. Consuming more calcium means nothing if the body doesn’t absorb it.1,6 Vitamin D increases calcium absorption from the small intestine, into the bloodstream, and finally to the bones. Other factors that positively affect bone health are as follows: weight-bearing exercise, tobacco avoidance, moderate alcohol intake.1
The effectiveness of calcium supplementation on bone mineral density varies according to two factors: dietary calcium intake and stage of life.8,9 Compared to Western cultures, Asian cultures do not commonly incorporate high-calcium level foods (such as milk, cheese and other dairy products) into the everyday diet.10-12 A study in elderly Thai women found that calcium supplementation of at least 500mg/day for 2 years resulted in noticeable changes in BMD (bone marrow density) at several skeletal study points. The study’s conclusion was this: “Calcium supplementation might be crucial in people who have low calcium intake at baseline”.9 In cases like these, supplementation may be needed, but the first choice is to consume calcium from foods.8
Another important factor that plays a role in the effectiveness of calcium supplementation is the stage in life of the patient, especially if that patient is a woman. Elderly postmenopausal women experience loss of “beneficial effects of estrogen on the stimulation of intestinal calcium absorption and reduction of renal calcium excretion as well as an increase in bone turnover rate.”9 In this case, vitamin D calcium supplementation would actually help to prevent early postmenopausal bone loss.6,9
The human body surely requires at least some calcium, but currently, there is no reliable method to determine an optimal amount of daily calcium intake based on criteria such as age, gender, height, and weight.4 Even in a study where the mean calcium intake was well above the daily recommended amount (1,200mg/day), hip fractures were still evident.4 This seemingly counterintuitive finding begs that further studies explain why meeting or even exceeding a healthy limit will produce a high incidence of hip fractures.
In light of these recent scientific findings, one shouldn’t rely on calcium supplements to prevent BMD complications. Furthermore, patients who currently have osteoporosis or a high risk of fracture should never replace prescription medication with calcium supplementation. Until further evidence surfaces, people of all ages hoping to prevent later development of osteoporosis should continue to strive for a balanced diet containing adequate protein, fruits, vegetables, calcium, and vitamin D.8 Would you still consider taking a calcium supplement for the insignificant increase in bone strength it provides?
- National Osteoporosis Foundation. Clinician’s guide to prevention and treatment of osteoporosis. Washington, DC: National Osteoporosis Foundation, 2010;1–56.
- Bolland MJ, Leung W, Tai V, et al. Calcium intake and risk of fracture: Systematic review.BMJ. 2015;351. doi: 10.1136/bmj.h4580.
- Tai V, Leung W, Grey A, Reid IR, Bolland MJ. Calcium intake and bone mineral density: Systematic review and meta-analysis.BMJ. 2015;351. doi: 10.1136/bmj.h4183.
- Cho K, Cederholm T, Lökk J. Calcium intake in elderly patients with hip fractures.Food & Nutrition Research. 2008;52:1-5.
- Cosman F, de Beur ,S.J., LeBoff MS, et al. Clinician’s guide to prevention and treatment of osteoporosis.Osteoporos Int. 2014;25(10):2359-2381.
- Kärkkäinen M, Tuppurainen M, Salovaara K, et al. Effect of calcium and vitamin D supplementation on bone mineral density in women aged 65-71 years: A 3-year randomized population-based trial (OSTPRE-FPS).Osteoporos Int. 2010;21(12):2047-2055.
- Kling, Juliana M.Clarke, Bart L.Sandhu,Nicole P. Osteoporosis prevention, screening, and treatment: A review.Journal of Women’s Health (15409996). 2014;23(7):563-572.
- Nieves JW. Skeletal effects of nutrients and nutraceuticals, beyond calcium and vitamin D.Osteoporos Int. 2013;24(3):771-786.
- Rajatanavin R, Chailurkit L, Saetung S, Thakkinstian A, Nimitphong H. The efficacy of calcium supplementation alone in elderly thai women over a 2-year period: A randomized controlled trial.Osteoporosis Int. 2013;24(11):2871.
- Kim HS, Kim JS, Kim NS, Kim JH, Lee BK (2007) Association of vitamin D receptor polymorphism with calcaneal broadband ultrasound attenuation in Korean postmenopausal women with low calcium intake. Br J Nutr 98:878–881
- Lau EM, Woo J, Lam V, Hong A (2001) Milk supplementation of the diet of postmenopausal Chinese women on a low calcium intake retards bone loss. J Bone Miner Res 16:1704–1709
- 12. Chee WS, Suriah AR, Zaitun Y, Chan SP, Yap SL, Chan YM (2002) Dietary calcium intake in postmenopausal Malaysian women: comparison between the food frequency questionnaire and three-day food records. Asia Pac J Clin Nutr 11:142–146