In a new study, researchers found that increasing protein intake beyond current recommendations has little to no benefit for bone health in healthy people.
The research was conducted by a team from the Department of Nutritional Sciences at the University of Surrey.
Protein is a chain of amino acid molecules and is a necessary part of our diet to help cell growth and repair.
However, the role of protein in bone health has been unclear.
Some research suggests a positive link and highlights dietary protein’s known ability to increase secretion of an insulin-like growth hormone which stimulates bone development.
Protein plays a role in increasing calcium absorption from the gut which is likely to be beneficial for bone mineralization.
But opponents argue that a high intake of protein, which is rich in sulphur amino acids, may be bad for bone health.
It increases body acidity resulting in a rise in osteoclast activity which absorbs bone tissue during growth and healing.
In the new study, the team examined if protein intake can impact bone health of adults and children.
They reviewed 127 previous studies published over a 40 year period, which focused on the link between protein and bone density, bone mineral content and the risk of osteoporotic fractures.
The researchers found that increasing protein intake had minimal benefit for bone health in healthy adults.
Only 4% of bone density and bone mineral content in adults is dependent on protein intake with the remaining 96 percent due to other factors.
For children, a strong link between protein intake and bone health was found, accounting for up to 14% of bone mineral content.
However, in healthy adults, protein supplementation via protein shakes or tablets was also not found to reduce the risk of fractures nor improve bone health.
The team says protein is an essential part of our diet and is required for a number of bodily functions including cell growth and repair.
In healthy adults, increased levels of protein have no extra benefit for bone health but equally is not harmful.
But in the older people who tend to have lower protein intakes and whose bones have become weaker with age, this may be different.
Future research is needed to examine the impact extra protein can have on this particular group.
The lead author of the study is Dr. Andrea Darling, Research Fellow at the University of Surrey.
The study is published in the journal Osteoporosis International.
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