Bones and Bone Health
Bones are the foundation of the body—the scaffolding on which everything else rests. Bone has several important functions. First, it provides the foundation for our mobility. Muscles connect to tendons, which are anchored to bones. Second, it supports and protects vital organs. Third, is serves as a mineral reserve (of calcium, magnesium, phosphorus, and other vital minerals) to support the needs of the body. And fourth, it holds tissues that allow for the growth of blood cells (the bone marrow) and the skeletal system itself.1
Bones are constantly being constantly being broken down and rebuilt in a process called the bone remodeling cycle. In this process, bones are resorbed by cells call osteoclast, then reformed by cells called osteoblasts. This process is highly responsive to the needs of the body and the environment, and is heavily influenced by external factors, such as diet, physical activity, and medications.
Bones mass naturally changes over the lifespan. Peak bone mass is usually achieved for both men and women by the mid-twenties. After that, everyone has a gradual decline. For men, the decline is very gradual. For women, a plateau occurs, followed by an accelerated period of bone loss for several years after menopause.2
When too much bone is lost, the bones become weak. Severe weakness is osteoporosis, sometimes also called a “thinning” of the bones. Osteopenia is another term, sometimes used to describe a less severe condition of weaker bones. Both are considered “silent” diseases because bone loss often occurs without you knowing it. Osteoporosis can predispose the bones to fracture with even minimal trauma. Fractures from osteoporosis can result in significant pain and disability. And osteoporosis is quite common. In the United States, 44 million Americans are at risk for osteoporosis. Ten million already have the disease. Women make up 80 percent of cases. Osteoporosis can be diagnosed using a test called central/axial dual-energy x-ray absorptiometry (typically called a DEXA scan). The DEXA scan provides a scoring system, called a T-score, that rates bone strength compared to a reference population of healthy individuals (20-29 yo). Normal is -1 or above, osteopenia is -1 to -2.5, and osteoporosis is -2.5 or below.3
While age is an important risk factor for the development of osteoporosis several other factors can accelerate the process of bone loss as well. Major factors that can contribute to osteoporosis are diet, physical activity, stress, smoking, alcohol use, low estrogen, and medications.4
So what changes can an individual make to improve bone health?
Nutrition - A well-balanced diet rich in in fruits, vegetables, whole grains, and healthy fats is the foundation for strong bones. Such a diet—often referred to as an “anti-inflammatory diet”—is associated with increased bone health and bone mass, and contains important nutrients such as potassium, vitamin K, Vitamin D, and vitamin C.5 In some cases, supplementation with vitamins may be beneficial to reach recommended levels. For oexample the Institute of Medicine recommends 1,000 mg of calcium daily for men and women up to age 50. For women over age 50 and men over age 70, intake should to 1,200 mg daily. Additionally, some people (especially individuals who are older or who don’t leave the house) may need vitamin D supplements to achieve the recommended intake of 600 to 800 IU (International Units) each day.6
Exercise - Bone, like muscle, responds to exercise by getting stronger. Bone density correlates with muscle mass.7 The best activities for your bones are weight-bearing and resistance exercise. Helpful exercises may include lifting weights, climbing stairs, walking, dancing, and movement practices like yoga, tai chi, and qi gong. The American College of Sports Medicine recommends 150 minutes of moderate-intensity aerobic activity per week and muscle-strengthening activity two or more times per week.8
Healthy lifestyle – Several lifestyle factors can contribute to bone loss. For example, women who smoke tend to go through menopause earlier, which leads to loss of estrogen and bone loss. Additionally, smoking may make it more difficult for the body to absorb calcium.9 Additionally, excessive alcohol can negatively affect bones. Smoking cessation and being careful about alcohol intake are important factors that can reduce osteoporosis risk.10
Medications – In some cases, patients may benefit from additional, specialized medications to help strengthen bones. The two primary classes are the bisphosphonates and the rank-ligand inhibitors. These all work in slightly different ways on the bone remodeling process.11
Bone health is an important part of overall health. If you have concerns about the strength of your bones, some changes in diet and activity may be helpful.
References
1. Marcus and Feldman’s Osteoporosis - 5th Edition. Accessed June 23, 2022. https://www.elsevier.com/books/marcus-and-feldmans-osteoporosis/dempster/978-0-12-813073-5
2. Bone biology | International Osteoporosis Foundation. Accessed June 23, 2022. https://www.osteoporosis.foundation/health-professionals/about-osteoporosis/bone-biology
3. Osteoporosis. Accessed June 23, 2022. https://www.endocrine.org/patient-engagement/endocrine-library/osteoporosis
4. Osteoporosis Overview | NIH Osteoporosis and Related Bone Diseases National Resource Center. Accessed June 23, 2022. https://www.bones.nih.gov/health-info/bone/osteoporosis/overview
5. Gagne L and Maizes V. Osteoporosis. In Integrative Medicine. Rakel D, ed. 4th edition. Elsevier; 2017.
6. Institute of Medicine (US) Committee to Review Dietary Reference Intakes for Vitamin D and Calcium. Dietary Reference Intakes for Calcium and Vitamin D. (Ross AC, Taylor CL, Yaktine AL, Del Valle HB, eds.). National Academies Press (US); 2011. Accessed June 23, 2022. http://www.ncbi.nlm.nih.gov/books/NBK56070/
7. Proctor DN, Melton LJ, Khosla S, Crowson CS, O’Connor MK, Riggs BL. Relative influence of physical activity, muscle mass and strength on bone density. Osteoporos Int J Establ Result Coop Eur Found Osteoporos Natl Osteoporos Found USA. 2000;11(11):944-952. doi:10.1007/s001980070033
8. Physical Activity Guidelines Resources. ACSM_CMS. Accessed June 23, 2022. https://www.acsm.org/education-resources/trending-topics-resources/physical-activity-guidelines
9. Yoon V, Maalouf NM, Sakhaee K. The effects of smoking on bone metabolism. Osteoporos Int J Establ Result Coop Eur Found Osteoporos Natl Osteoporos Found USA. 2012;23(8):2081-2092. doi:10.1007/s00198-012-1940-y
10. Berg KM, Kunins HV, Jackson JL, et al. Association between alcohol consumption and both osteoporotic fracture and bone density. Am J Med. 2008;121(5):406-418. doi:10.1016/j.amjmed.2007.12.012
11. Hanley DA, Adachi JD, Bell A, Brown V. Denosumab: mechanism of action and clinical outcomes. Int J Clin Pract. 2012;66(12):1139-1146. doi:10.1111/ijcp.12022