The good, the bad, and the ugly of calcium supplementation: a review of calcium intake on human health

Kelvin Li,1,* Xia-Fang Wang,2,3,* Ding-You Li,4 Yuan-Cheng Chen,2 Lan-Juan Zhao,1 Xiao-Gang Liu,5 Yan-Fang Guo,6 Jie Shen,2 Xu Lin,2 Jeffrey Deng,1 Rou Zhou,2 Hong-Wen Deng1,7 1Center for Bioinformatics and Genomics, Department of Global Biostatistics and Data Science, Tulane University, New Orleans, LA 70112, USA; 2Department of Endocrinology and Metabolism, The Third Affiliated Hospital of Southern Medical University, Guangzhou, Guangdong 510630, People’s Republic of China; 3Department of Endocrinology and Metabolism, Hengyang Central Hospital, Hengyang, Hunan 421000, People’s Republic of China; 4Department of Gastroenterology, Children’s Mercy Kansas City, University of Missouri Kansas City School of Medicine, Kansas City, MO 64108, USA; 5School of Life Science and Technology, Xi’an Jiao Tong University, Xi’an, Shanxi 710049, People’s Republic of China; 6Institute of Bioinformatics, School of Basic Medical Science, Southern Medical University, Guangzhou, Guangdong 510515, People’s Republic of China; 7School of Basic Medical Science, National Clinical Research Center for Geriatric Diseases, Xiangya Hospital, Central South University, Changsha, Hunan 410078, People’s Republic of China *These authors contributed equally to this work Abstract: Calcium is an important integrative component of the human body and critical for human health. It has been well established that calcium intake is helpful in the prevention and treatment of osteoporosis, which has become one of the most serious public health problems across the world. However, community-dwelling adults with and without osteoporosis are rarely concerned or even not aware of the potential side effects of high or inappropriate doses of calcium intake. Some recent studies have revealed that excessive calcium intake might increase the risks of cardiovascular diseases. The purpose of this article was to review the health benefits, costs, and consequences of calcium supplementation on osteoporosis/osteoporotic fractures, cardiovascular events, kidney stones, gastrointestinal diseases, and other important diseases. In the end, we suggest that calcium supplementation should be prescribed and taken cautiously, accounting for individual patients’ risks and benefits. Clearly, further studies are needed to examine the health effects of calcium supplementation to make any solid recommendations for people of different genders, ages, and ethnicities. Keywords: calcium, osteoporosis, osteoporotic fractures, cardiovascular diseases, kidney stones, gastrointestinal diseases