What scientific argument can be presented to question that study?
I am concerned because i have osteoporosis.
jean-claude
>> UniSci - Daily University Science News
>>
>> A change in blood acidity caused by a high-protein diet accelerates
>> osteoporosis by depleting bones of their calcium, say researchers at
>> the University of Rochester. Their study, which appears in today's
>> issue of the American Journal of Physiology, reveals for the first
>> time how bones sacrifice themselves to compensate for the
>> acid-producing foods we eat.
>>
>> "When we eat, we generate acid," explains David A. Bushinsky, M.D.,
>> lead author of the study and professor of Medicine and of Pharmacology
>> and Physiology at Strong Memorial Hospital at the University of
>> Rochester. "These acids are ultimately excreted by the kidneys, but as
>> we age, our kidneys don't function so well. If the kidneys can't keep
>> up with our appetite, the bones step in and absorb the excess acid.
>> That's good in the short term, but in the process the bones surrender
>> calcium, phosphorus, sodium and everything they should be keeping to
>> stay strong."
>>
>> The process is called metabolic acidosis and it can become a problem
>> for a middle-aged or older person whose kidneys are not working as
>> efficiently as those of a younger person's. Not only does the bone
>> trade off its calcium for the blood's acid, but the acid environment
>> hinders osteoblasts, the cells that naturally rebuild damaged bone.
>>
>> "An older woman with kidney trouble should definitely watch how much
>> protein she eats," says Bushinsky. As much as 30 percent of
>> post-menopausal white women, the group at greatest risk, have
>> osteoporosis. Protein generates more acid than other foods, and the
>> proteins in red meat generate more acid than those in fish or poultry.
>> Vegetable proteins give rise to the least amount of acid.
>>
>> Though scientists have suspected that high levels of acid in the blood
>> contribute to osteoporosis, this is the first time researchers have
>> been able to confirm that the bones are actually deteriorating. Using
>> a prototype machine called an "ion microprobe," Bushinsky was able to
>> zoom in and identify what made up each layer of a mouse bone.
>>
>> Up until now, researchers had to test the entire bone, and so would
>> easily miss the loss of calcium that occurred only at the surface. The
>> ion microprobe strips away layers of bone like a leaf-blower whisking
>> away the top dry leaves while the wet ones stay on the lawn. Then it's
>> just a matter of collecting the blown fragments and analyzing them.
>>
>> Bushinsky found that in just seven days, mice experiencing metabolic
>> acidosis had measurable depletion of calcium in their femurs. "But the
>> calcium depletion probably started just days, even hours after the
>> blood became acidic," he explains.
>>
>> Some medications and diseases can hinder the kidneys' ability to keep
>> the blood pH at healthy levels. The two most common diseases that
>> limit kidney function are hypertension and diabetes.
>>
>> This study is funded entirely by the National Institutes of Health.
>> The ion microprobe was developed by Riccardo Levi-Setti, Ph.D., of the
>> University of Chicago. - By Jonathan Sherwood
>> [Contact: [3]Jonathan Sherwood]
>> 3. mailto:[log in to unmask]
>>
>> 05-Nov-1999
>>
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