Protein: Beneficial for Bone Health Too

The benefits of protein for bone health

Maintaining good bone health is essential at every stage of life. Bone mineral density declines substantially with age, increasing the risk of osteoporosis and fractures, especially in older adults. Healthy bone density is not only important later in life: bone health resembles the foundations of a house that we build from birth, so what we do while young affects us as we age.

Bone health is especially relevant to athletes. Sport can be a double-edged sword: the mechanical stress imposed on bones during impact exercise such as running and jumping promotes osteogenesis—the formation of bone tissue—and is therefore beneficial, but excessive stress may increase fracture risk. People who practice low-impact sports such as swimming or cycling also appear to have lower bone mineral density than those in impact sports (1,2).

Protein and bone health

Alongside the type and amount of exercise, nutrition is a key determinant of bone health. Adequate energy intake is essential to prevent bone breakdown, but protein is another major and often overlooked factor. A traditional hypothesis proposed that high protein intake, especially from meat, could acidify the body, increase urinary calcium excretion and negatively affect bone through demineralization. Growing evidence shows not only that protein is not harmful to bone, but that it may be highly beneficial.

Large epidemiological studies in older adults show that those with the highest protein intake, especially animal protein, have greater bone mineral density (3). Higher protein intake is also associated with lower fracture risk (4). Greater protein intake therefore appears beneficial for limiting age-related bone loss. But what about young people and athletes?

Although repeated mechanical stress from exercise benefits bone health, very intense or prolonged exercise can increase markers of bone breakdown (5). Consuming a carbohydrate-protein supplement after fatiguing exercise has been shown to reduce markers of bone resorption while increasing markers of bone formation (6).

One study measured athletes' bone mineral density before and after 12 weeks of strength training, a powerful bone-health stimulus. Some consumed a high-protein diet, including supplements before and after training, while others consumed a normal amount (7). Overall gains in bone mineral density were small, probably because the athletes already had high density and the program was short. Importantly, however, only those with high protein intake increased bone mineral density (7).

Conclusions

Although most evidence on protein benefits focuses on muscle mass, growing evidence shows that high protein intake can also benefit bone health. These benefits are most apparent in older adults but may also be highly relevant to young people and athletes, particularly during high training loads and/or energy deficits.

Author: Pedro Valenzuela of Fissac.com, researcher in the Physiology Unit at the University of Alcalá and the Performance Monitoring Unit at the Sports Medicine Center (AEPSAD, Madrid High Performance Center).

References

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2. Duncan CS, Blimkie CJR, Howman-Giles R, Briody JN, COWELL CT, BURKE ST. Bone mineral density in adolescent female athletes: relationship to exercise type and muscle strength. Med Sci Sports Exerc. 2002;34(2):286–94.
3. Groenendijk I, Grootswagers P, Santoro A, Franceschi C, Bazzocchi A, Meunier N, et al. Protein intake and bone mineral density: Cross-sectional relationship and longitudinal effects in older adults. J Cachexia Sarcopenia Muscle. 2023;14(1):116–25.
4. Weaver AA, Tooze JA, Cauley JA, Bauer DC, Tylavsky FA, Kritchevsky SB, et al. Effect of Dietary Protein Intake on Bone Mineral Density and Fracture Incidence in Older Adults in the Health, Aging, and Body Composition Study. Journals Gerontol – Ser A Biol Sci Med Sci. 2021;76(12):2213–22.
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7. Chung CW, Kuo CH, Huang HY, Alkhatib A, Tseng CY, Huang CY, et al. High-protein supplementation facilitates weight training–induced bone mineralization in baseball players. Nutrition [Internet]. 2020;75–76:110760. Available from: https://doi.org/10.1016/j.nut.2020.110760