A high protein diet may be better for bone health, according to a new study which examined the effects of the amount and source of dietary protein on rats´ bones.
Researchers at the University of Granada in Spain, who conducted the experiments, said that hyperproteic diets could be beneficial for groups of people with bone disease problems, such as the elderly or women after the menopause.
As part of their work, the researchers compared the benefits of vegetal protein, such as soy protein, with protein from animal origins, such as whey protein. They concluded that vegetal protein is preferable to animal protein because the former increased the level of calcium in bones by as much as 7%.
The experiments involved 140 rats who were divided into four subgroups, each of which was given a different diet over a 12-week period. Two of the rodent groups were fed a normoproteic diet (10% rich), half of them with soy protein and the other half with whey protein. The other two groups were given two different types of hyperproteic diets (45% rich) based on soy or whey protein.
Results demonstrated that rats fed with a hyperproteic diet maintained better bone properties than those given a normoproteic diet. The group fed with soy protein had 7% more calcium in their bones and a thicker diaphyseal cortical area than those fed with the whey protein diet. Negative side effects related to acidity, such as urea in plasma (46% higher) and urinary pH (8% more acid), were reduced in the groups that consumed soy as a protein source.
High protein diets are common among athletes and people trying to lose weight, but there is still no consensus on the effects of such diets, the researchers pointed out.
“The impact that the type and the amount of protein which we consume have upon our health is a highly controversial topic within the scientific community,” noted two of the authors of this study, Virginia A. Aparicio Garcia Molina and Elena Nebot, researchers from the Physiology Department at the University of Granada.
In order to draw conclusions about human bone health, the findings of this study would need to be confirmed in human subjects.
“We would recommend a case by case study supervised by professionals, and approach the subject taking into consideration the advantages and disadvantages presented by hyperproteic diets, besides each individual´s personal features,” the researchers said.