Essential amino acid requirements
f-thomas at students.uiuc.edu
Tue Dec 14 15:01:55 EST 1999
On Tue, 14 Dec 1999, Stuart Dunn wrote:
> Recent studies show that soy protein does not increase calcium loss, but
> animal protein does.
But animal protein also reduces the risk of hip fracture. (probably
because vegetable protein sucks as a source of lysine)
Munger RG. Cerhan JR. Chiu BCH.
Prospective study of dietary protein intake and risk of hip fracture in
American Journal of Clinical Nutrition. 69(1):147-152, 1999 Jan.
Background: The role of dietary protein intake in osteoporosis remains
controversial. Protein is an important structural component of bone and
protein supplementation improves the medical outcome of hip fracture
patients, but it is unknown whether protein intake can reduce the
incidence risk of hip fracture.
Objective: The relation between intake of protein and other nutrients and
subsequent incidence of hip fracture was evaluated.
Design: Nutrient intake was assessed with a food-frequency questionnaire
in a cohort of Iowa women aged 55-69 y at baseline in 1986. Incident hip
fractures were ascertained through follow-up questionnaires mailed to
participants in 1987 and 1989 and verified by physician reports.
Results: Forty-four cases of incident hip fractures were included in the
analyses of 104 338 person-years (the number of subjects studied times the
number of years of follow-up) of follow-up data. The risk of hip fracture
was not related to intake of calcium or vitamin D, but was negatively
associated with total protein intake. Animal rather than vegetable sources
of protein appeared to account for this association. In a multivariate
model with inclusion of age, body size, parity, smoking, alcohol intake,
estrogen use, and physical activity, the relative risks of hip fracture
decreased across increasing quartiles of intake of animal protein as
follows: 1.00 (reference), 0.59 (95% CI: 0.26, 1.34), 0.63 (0.28, 1.42),
and 0.31 (0.10, 0.93); P for trend = 0.037.
Conclusion: Intake of dietary protein, especially from animal sources, may
be associated with a reduced incidence of hip fractures in postmenopausal
women. [References: 41]
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