Take account of calcium excretion
As far as I can see, this research does not address the issue of
calcium loss through the kidneys, which must accompany the excretion of
the metabolites of excessive protein. In Third World countries, average
dietary protein intake is significantly lower than in the First World: my
understanding is that this is a major factor in their relatively low
incidence of osteoporosis.
Dairy products have high levels of both calcium and protein, perfect
for calves, but not necessarily so good for humans. Those of us who are
vegans get most of our calcium from foods with lower levels of protein,
such as green leafy vegetables, broccoli, swede, almonds, and brazils, as
well as some from high-protein foods like tofu and fortified soya milk.
I am uncomfortable about the way the dairy industry promotes their
products as a good source of calcium, because, if the above is true, they
are not so good at providing calcium which is retained by the human body.
I would be very keen to see more research done in this field,
specifically some which monitors protein as well as calcium intake.
Competing interests: No competing interests