Fred Thomas wrote:
>> 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.
No. Some studies have shown that vegans actually have lower risks of hip
fractures, even without controlling for calcium intake. Others show the
opposite results, but we can assume that there are vegans who neglect to
limit salt and caffeine and don't take calcium pills.
(probably
> because vegetable protein sucks as a source of lysine)
I suggest that you get a calorie counter that lists amino acids before
you automatically conclude that plant protein is deficient in any amino
acid.
>> Authors
> Munger RG. Cerhan JR. Chiu BCH.
> Title
> Prospective study of dietary protein intake and risk of hip fracture in
> postmenopausal women
> Source
> American Journal of Clinical Nutrition. 69(1):147-152, 1999 Jan.
> Abstract
> 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
Notice the words "and other nutrients." They might have given the women
milk or other calcium supplements.
and
> subsequent incidence of hip fracture was evaluated.
>> Design: Nutrient intake was assessed with a food-frequency questionnaire
Food frequency questionaires are unscientific. If the study had been
conducted properly the number of grams of protein would have been
counted, and so would the number of milligrams of sodium, calcium,
magnesium, and caffeine. Also, you can't track nutrient intake after the
hip fracture and expect that to reflect what the women were eating
beforehand. What if the fracture scared them into drinking more milk?
> 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.
So why do Eskimo women, who ate an average of 350 grams of animal
protein a day, had ate fish livers, refrained from using alcohol or
caffeine, got plenty of excercise, and got over 2000mg a day from bone
meal have the highest rates of osteoperosis in the world?
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]
Food intake questionaires are useless.
