A Bone to Pick

Bone is constantly in flux. It is being broken down to remove old bone (resorption) and laid down to build new bone (deposition). This occurs in a natural homeostasis to ensure bone is healthy. However, with advancing age or even due to severe hormonal imbalances in younger people, this homeostasis begins to faulter. Oestrogen is a key factor in maintaining and building bone mass, and when it declines (as occurs with menopause) so too does bone density. Inflammation, oxidative stress, poor nutrient intake or absorption, inadequate sun exposure, and lack of exercise also contribute to reduced bone mass.

Peak bone mass is achieved in our 20s and 30s, after which there is a gradual decline that most rapidly occurs post-menopause (1). Approximately 30% of American and European post-menopausal women have osteoporosis (2). Osteoporosis involves a reduction in bone mass and higher risk of fragility fractures. Osteopenia occurs when bone density is low, but not as severe as osteoporosis. Bones of the spine, hips, and wrists are most vulnerable to fracture. A hip fracture in older people can have dire consequences, with 40% of people becoming institutionalised due to reduced independence, and over 30% passing away within one year (2). This is why it is so important that we take care of our bones throughout our lives, and luckily there’s a lot that we can do!

Bones and Exercise

Exercise can address all modifiable fracture risk factors: bone strength, fall risk, and fall impact (2). Bone requires heavy mechanical loads to stimulate and improve density and microarchitecture to both make them strong and keep them strong (3). Low-impact exercises like walking are often recommended for older adults, however this does not have a positive effect on bone density. In fact, walking can increase fall risk while providing no bone-building benefit in osteoporotic people (3).

A 2010 study found that, despite strong public health messages, middled-aged women reduce their physical activity up to 40%. Additionally, only 18% and 11% of women aged 45-64 and 65-74 respectively engage in the suggested two or more days of strength training (4). Resistance exercise and impact training have been shown to be most effective to build bone. This encompasses using free weights, machine weights, and resistance bands, as well as plyometric or jumping movements (3). Movements that target muscles attached to the hip and spine provide the most effective loads to produce bone-building outcomes. Resistance exercise not only increases bone mass but also changes the microstructure of bone. It is possible that the bone-building benefits of exercise are underestimated, as these structural changes can provide significant improvements in strength independently of bone density. To optimise bone health, resistance training should occur in short bursts, be above the minimal strain threshold, and continue to be progressively increased (5). Aerobic exercise also has a benefit as it optimises enzymes that activate bone-building cells (6).

Bones and Diet

Many nutrients are required for healthy bones. These include calcium, vitamin K, magnesium, and boron, which can be obtained by eating a high-quality whole food diet, high in fruits and vegetables (7). Vitamin D is required for calcium absorption and is best acquired from sunshine or through supplementation. Calcium absorption and vitamin D synthesis are reduced with ageing, which can lead to bone loss (8). However, high-dose calcium supplements are not recommended to prevent osteoporosis as the benefit received from them is short-lived and risk of heart attack and stroke is increased due to arterial calcification (11). Vitamin K can be used to help mitigate this risk, while also assisting with increasing bone formation (12). There are two types of vitamin K which are both beneficial: vitamin K2 is most readily attained through supplementation, whereas vitamin K1 is plentiful in green leafy vegetables.

Inflammation and oxidative stress can also lead to poor bone density. These are both driven by poor gut health, and highly processed diets that are low in fibre and micronutrients (9). Phyto-oestrogens found in soy can support oestrogenic activity in bone for post-menopausal women (10). Soy foods (especially tofu) also happen to be high in calcium and protein - so are a win, win, win for our bones!

Body weight is also an important factor that contributes to bone health, and is very much impacted by diet. Those who are underweight, especially women, are more prone to fracture, whereas obesity (specifically high body fat) is associated with lower bone mineral density (13). Therefore, it is important with age to avoid underweight and obesity through appropriate dietary planning. Excess fat leads to inflammation, and has even been proposed to hinder the development of bone cells (13). Having a diet that is nutrient dense and higher in protein is crucial, as our needs for protein increase with age (14). This assists in preventing sarcopenia or loss of muscle mass, something which is so key for bone health, but also a proxy of our exercise levels!

Bones and Stress

Inflammation and oxidative stress, leading factors in loss of bone density, are driven by psychological stress. Mindfulness and social support networks are important in alleviating these issues and improving wellbeing. Yoga and meditation have been shown to reduce inflammatory biomarkers and improve bone density (15).

If you would like support to improve your bone health I am available for holistic health consultations encompassing nutrition, exercise, and Yoga. I can also help with a range of other health and lifestyle concerns. Click here to find out more.

By Jessica Zabow
Clinical Nutritionist (BHSc)
& Yoga Teacher (RYT500)

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References

1. Chen, J., Chen, Y., Tsai, M., Chiou, J., Lee, W., Tsao, C., ... Chie, W. (2017). Predicting the risk of osteopenia for women aged 40-55 years. Journal of the Formosan Medical Association, 116(11), 888-896. https://doi.org/10.1016/j.jfma.2017.01.003

2. Daly, R.M., Dalla Via, J., Duckham, R.L., Fraser, S.F., & Wulff Helge, E. (2018). Exercise for the prevention of osteoporosis in postmenopausal women: An evidence-based guide to the optimal prescription. Brazilian Journal of Physical Therapy, 23(2), 170-180. https://doi.org/10.1016/j.bjpt.2018.11.011

3. Hong, A.R., & Kim, S.W. (2018). Effects of resistance exercise on bone health. Endocrinology and Metabolism, 33(4), 435-444. https://doi.org/10.3803/EnM.2018.33.4.435

4. Seguin, R.A., Economos, C.D., Palombo, R., Hyatt, R., Kuder, J., & Nelson, M.E. (2010). Strength training and older women: A cross-sectional study examining factors related to exercise adherence. Journal of Aging and Physical Activity, 18(2), 201-208. https://doi.org/10.1123/japa.18.2.201

5. Watson, S., Weeks, B., Weis, L., Harding, A., Horan, S., & Beck, B. (2018). High-intensity resistance and impact training improves bone mineral density and physical function in postmenopausal women with osteopenia and osteoporosis: The LIFTMOR randomised controlled trial. Journal of Bone and Mineral Research, 33(2), 211-220. https://doi.org/10.1002/jbmr.3284

6. Bendetti, M.G., Furlini, G., Zati, A., & Mauro, G.I. (2018). The effectiveness of physical exercise on bone density in osteoporotic patients. BioMed Research Internationali, 2018(4840531), 1-10. https://doi.org/10.1155/2018/4840531

7. Sahni, S., Mangano, K.M., McLean, R.R., Hannan, M.T., & Kiel, D.P. (2015). Dietary approaches for bone health: Lessons from the Framingham Osteoporosis Study. Current Osteoporosis Reports, 13(4), 245-255. https://doi.org/10.1007/s11914-015-0272-1

8. Hill, T.R., & Aspray, T.J. (2017). The role of vitamin D in maintaining bone health in older people. Therapeutic Advances in Musculoskeletal Disease, 9(4), 89-95. https://doi.org/10.1177/1759720X17692502

9. Bartolozzi, E. (2015). The natural approach to osteoporosis. Clinical Cases in Mineral and Bone Metabolism, 12(2), 111-115. https://doi.org/10.11138/ccmbm/2015.12.2.111

10. Cancelo-Hidalgo, M.J. (2018). Isoflavones and bone health. Revista de Osteoporosis y Metabolismo Mineral, 10(4), 139-145.
https://doi.org/10.4321/S1889-836X2018000400006

11. Reid, I.R., & Bolland, M.J. (2020). Calcium and/or vitamin D supplementation for the prevention of fragility fractures: Who needs it? Nutrients, 12(4), 1-9. https://doi.org/10.1007/10.3390/nu12041011

12. Wasilewski, G.B., Vervloet, M.G., & Schurgers, L.J. (2019). The bone-vascular axis: Calcium supplementation and the role of vitamin K. Frontiers in Cardiovascular Medicine, 6(6),1-16. https://doi.org/10.3389/fcvm.2019.00006

13. Chen, Y-Y., Fang, W-H., Wang, C-C., Kao, T-W., Chang, Y-W., Wu, C-J., Zhou, Y-C., Sun, Y-S., & Chen, W-L. (2018). Body fat has stronger associations with bone mass density than body mass index in metabolically healthy obesity. PLoS ONE, 13(11), 1-11. https://doi.org/10.1371/journal.pone.0206812

14. Baum, J.L., Kim, I-Y., & Wolfe, R.R. (2016). Protein consumption and the elderly: What is the optimal level of intake? Nutrients, 8(6), 1-9. https://doi.org/10.3390/nu8060359

15. Kelly, R.R., McDonald, L.T., Jensen, N.R., Sidles, S.J., & LaRue, A.C. (2019). Impacts of psychological stress on osteoporosis: Clinical implications and treatment interac5ons. Frontiers in Psychiatry, 10(1), 1-21. https://doi.org/10.3389/fpsyt.2019.00200