Calcium is a fundamental element of the body and is highly important in bone mineralization, primarily related to bone health, which includes the formation and maintenance of the structure and rigidity of the skeleton. Since Calcium cannot be produced by the human body, it needs to be ingested with calcium-containing food. (1) An ideal calcium intake helps to build up an adequate peak bone mass, important for strong bones in childhood and adolescence and a minimized loss of bone mass during adulthood. A calcium deficiency leads to an increased risk of sustaining osteoporosis, a disease in which the density and quality of bones are reduced. A systematic review from 2006 that included 19 studies involving 2859 children found that calcium supplementation had a small effect on total body bone mineral content and upper limb bone mineral density. This effect persisted after the end of supplementation only for the upper limb bone mineral density. (2) Newer data from the Women´s Health Initiative study, a meta-analysis showed a 15% reduction in the incidence of fractures and a 30% reduction in hip fractures in middle-aged to older adults who supplemented calcium and vitamin D. (3)

There is a study that examined a correlation between dietary calcium intake and height growth. According to China Health and Nutrition Survey (CHNS), non-linear regression found that boys with dietary calcium intakes below 327 mg/d had shorter adult stature, and those taking over 566 mg/d had faster height growth whether adjusting for physical exercises level or not. (4) It suggests that in boys with plant-based diets, higher dietary calcium intake during adolescence is associated with faster height growth, calcium intake below 300 mg/d may result in shorter adult stature. 

There is also evidence that calcium can help prevent or control high blood pressure. In a 2016 study, 42 pregnant women took supplements containing calcium and vitamin D and several of their metabolic markers improved, including blood pressure and markers of inflammation. (5) Other research has shown that the children of women who took calcium supplements while pregnant have lower blood pressure at age seven than the children of mothers who did not take them. (6) Calcium can also be good for preventing obesity in children. Studies have associated low calcium intake with a high body mass index (BMI) and high body fat percentage (7) and study of overweight and obese college students showed those given a supplement containing 600 mg of calcium and 125 IUs of vitamin D lost more body fat on a calorie-restricted diet than those who did not receive the supplement. (8) 

According to one large study, calcium from dairy products and supplements may lower the risk of colon cancer. (9) It also may reduce PMS symptoms and play a role in preventing certain cancers. According to some research, calcium with vitamin D, for instance, may help protect against breast cancer in premenopausal women. Doctors also use calcium to control high levels of magnesium, phosphorus, and potassium in the blood. 

References: 

1. Grüdtner VS, Weingrill P, Fernandes AL. Aspectos da absorção no metabolismo do cálcio e vitamina D. Rev. Bras. Reumatol. 1997; 37 (3): 143-51.

2. Tania Winzenberg, Kelly Shaw, Jayne Fryer, Graeme Jones Effects of calcium supplementation on bone density in healthy children: meta-analysis of randomised controlled trials BMJ. 2006 Oct 14; 333 (7572): 775. 

3. Weaver CM, Alexander DD, Boushey CJ, Dawson-Hughes B, Lappe JM, LeBoff MS, Liu S, Looker AC, Wallace TC, Wang DD. Calcium plus vitamin D supplementation and risk of fractures: an updated meta-analysis from the National Osteoporosis Foundation. Osteoporos Int. 2016 Jan; 27 (1): 367-76. 

4. Aiping Fang, Keji Li, He Li, Meihan Guo, Jingjing He, Xin Shen, Jie Song Low Habitual Dietary Calcium and Linear Growth from Adolescence to Young Adulthood: results from the China Health and Nutrition Survey Sci Rep. 2017; 7: 9111. 

5. Asemi Z, Samimi M, Siavashani MA, Mazloomi M, Tabassi Z, Karamali M, Jamilian M, Esmaillzadeh A. Calcium-Vitamin D Co-supplementation Affects Metabolic Profiles, but not Pregnancy Outcomes, in Healthy Pregnant Women. Int J Prev Med. 2016 Mar 1; 7:49. 

6. Jamshidi F, Kelishadi R. A systematic review on the effects of maternal calcium supplementation on offspring's blood pressure. J Res Med Sci. 2015 Oct; 20 (10): 994-9. 

7. Bueno MB, Cesar CL, Martini LA, Fisberg RM. Dietary calcium intake and overweight: an epidemiologic view. Nutrition. 2008 Nov-Dec; 24 (11-12): 1110-5. 

8. Zhu W, Cai D, Wang Y, Lin N, Hu Q, Qi Y, Ma S, Amarasekara S. Calcium plus vitamin D3 supplementation facilitated fat loss in overweight and obese college students with very-low calcium consumption: a randomized controlled trial. Nutr J. 2013 Jan 8; 12:8. 

9. Park Y, Leitzmann MF, Subar AF, Hollenbeck A, Schatzkin A. Dairy food, calcium, and risk of cancer in the NIH-AARP Diet and Health Study. Arch Intern Med. 2009 Feb 23; 169 (4): 391-401.