The rumors are true, getting enough calcium is a mandatory prerequisite to having healthy teeth and bones. There are other factors involved, but adequate calcium levels are definitely a large part of the equation. When you lack sufficient levels of calcium, your body will extract it from your bones, and this can lead to diminished bone health, including osteoporosis. It doesn’t stop there. If your calcium levels are deficient, you can experience other problems besides a weakened skeletal system.
Calcium Deficiency and Bone Health
As children, calcium’s role in developing strong bones and healthy teeth is a message that radiates the airwaves. I don’t agree with the milk mustaches, but it is true that adequate calcium intake is particularly important during the first two decades of life for proper skeletal development and the remaining decades to maintain skeletal health.  According to the Children’s National Medical Center at the Center for Clinical and Community Research in Washington DC, calcium deficiency can contribute to the risk of bone fractures in children.  Later in life, osteoporosis is often the concern as calcium deficiency is a major risk factor for osteoporosis.
Osteoporosis is a bone disorder that affects women four times as often as men and is a factor in 1.3 million bone fractures every year. According to research published by the Gerontology Program at the University of Northern Colorado, the three common strategies used to stabilize bone mass are hormone replacement, a nutritional approach (diet or supplements), and exercise.  The Department of Cardiology at Ziekenhuis Oost-Limburg in Belgium recommends a combination of calcium and vitamin D supplementation to address osteoporosis. Calcium requirements for women increase during menopause and meeting them is paramount to alleviating the risks associated with developing postmenopausal osteoporosis. 
Rickets is another bone disease that is often due to severe calcium (and vitamin D) deficiency. The disease is characterized by severe bone deformities, especially in the legs and wrists. Although rickets is no longer a major problem in the United States, it remains a major problem in other parts of the world and shouldn’t be dismissed. 
Calcium Deficiency and the Cardiovascular System
According to the National Center for Geriatrics and Gerontology, calcium deficiency can deteriorate bone metabolism and the cardiovascular system.  The Department of Geriatric Medicine at Osaka University Medical School evaluated available research and found it to suggest that calcium deficiency contributes to the development of high blood pressure. 
Calcium Deficiency and Intestinal Health
Celiac disease is an intestinal ailment that frequently involves less-than-optimal nutrient absorption. Deficiencies in calcium and vitamin D are common in adults with celiac disease and calcium and vitamin D supplementation is often recommended for adults with celiac disease.  Furthermore, inflammatory bowel disease is, unfortunately, also a common disorder that affects over a million americans and, according to the University of Pennsylvania School of Medicine, has costs estimated to be over 13 billion dollars per year. Calcium absorption can be a problem with IBD and weakened bone density has specifically been cited as a concern. 
Calcium Deficiency and Brain Health
Links between calcium deficiency and Alzheimer’s disease have been observed. According to Japan’s Kobe University, proper calcium intake, taken with an active form of vitamin D, is a positive step forward to lessening some of the risks associated with Alzheimer’s disease.  Additionally, deficient calcium levels have been observed in adults with anxiety and headache. 
Calcium from Real Food and Smart Calcium Supplementation
There are two ways to get calcium- food or supplementation. Plenty of vegetables, such as kale and broccoli, are high in calcium and certain dairy products may also be acceptable; though I don’t recommend pasteurized milk from factory cows. If you find it difficult to get enough dietary calcium, supplementing is the answer and there many calcium supplements to choose from. Calcium orotate, as opposed to calcium citrate or calcium carbonate, is the only form of calcium I recommend because it can penetrate cell membranes the most effectively and deliver calcium throughout your body.
- Bronner F. Calcium nutrition and metabolism. Dent Clin North Am. 2003 Apr;47(2):209-24. Review.
- Ryan LM. Forearm fractures in children and bone health. Curr Opin Endocrinol Diabetes Obes. 2010 Dec;17(6):530-4. doi: 10.1097/MED.0b013e32833e9c8b. Review.
- Roberto KA. Osteoporosis and older women:. J Women Aging. 1993;5(3-4):43-59. doi: 10.1300/J074v05n03_06.
- Verbrugge FH, Gielen E, Milisen K, Boonen S. Who should receive calcium and vitamin D supplementation? Age Ageing. 2012 Sep;41(5):576-80. doi: 10.1093/ageing/afs094. Epub 2012 Aug 8.
- Nordin BE, Horsman A, Marshall DH, Simpson M, Waterhouse GM. Calcium requirement and calcium therapy. Clin Orthop Relat Res. 1979 May;(140):216-39.
- Prentice A. Nutritional rickets around the world. J Steroid Biochem Mol Biol. 2012 Dec 7. doi:pii: S0960-0760(12)00251-8. 10.1016/j.jsbmb.2012.11.018.
- Hosoi T. [Calcium metabolism and anti-aging of bone]. Clin Calcium. 2008 Jul;18(7):918-22. doi: CliCa0807918922. Review. Japanese.
- Mikami H, Ogihara T, Tabuchi Y. Blood pressure response to dietary calcium intervention in humans. Am J Hypertens. 1990 Aug;3(8 Pt 2):147S-151S. Review.
- Szymczak J, Bohdanowicz-Pawlak A, Waszczuk E, Jakubowska J. Low bone mineral density in adult patients with coeliac disease. Endokrynol Pol. 2012;63(4):270-6.
- Lichtenstein GR. Management of bone loss in inflammatory bowel disease. Semin Gastrointest Dis. 2001 Oct;12(4):275-83.
- Fujita T. [Alzheimer disease and calcium]. Clin Calcium. 2004 Jan;14(1):103-5. Japanese.
- Janiri L, Gallo G, Nicoletti W. Calcium deficiency and supraorbital headache: a clinical study of adult subjects. Cephalalgia. 1986 Dec;6(4):211-8.