Do high protein diets make your bones weaker?
The recent popularity of high protein diets, such as the Atkins
or South Beach Diet, has led to fears about their effect on the
strength of your bones.
The more protein in your diet, the more calcium you lose in your
urine. The source of calcium was assumed to be from bone. However,
a few studies suggest that people eating more protein have stronger
bones.
High protein diets
One recent trial, published in the April 2004 edition of the Journal
of Bone and Mineral Research, confirms that middle-aged people
eating more protein have fewer hip fractures resulting from osteoporosis
[1].
Almost 1,200 residents of Utah from 50-89 years of age who experienced
hip fractures were compared with over 1,300 control subjects.
Higher protein intake was associated with a significant decrease
in hip fracture among those under the age of 70 years.
Even a modest increase in protein from the group eating the least
protein was associated with a 50% decrease in fracture rate. No
effect was seen in people 70 or older.
In all groups, calcium from the diet was low. One-third of men
and almost two-thirds of women used calcium supplements.
There is also research to show that even when eating half the recommended
dietary intake of calcium — a practice common among American
women — volunteers can eat more protein (20% versus 12% of
total calories) mostly as meat, without having an adverse effect
on calcium retention [5].
The high-meat diet consisted of 20% of daily calories as protein
(about 117 grams) including 10.5 ounces of meat. The low-meat diet
consisted of 12% protein, including 1.5 ounces of meat.
Meat contains substantial amounts of potassium and phosphorus,
which reduce urinary calcium loss.
Most people think that calcium is the most important nutrient for
bone health. Because of this, dairy foods (such as milk, yogurt
or cheese) are usually recommended to women who want to protect
against osteoporosis.
But contrary to popular belief, not all dairy foods promote bone
health.
The high calcium content of processed cheese products, for instance,
is offset by their high sodium and protein content, which can increase
calcium loss. Cottage cheese is relatively low in calcium and potassium,
and high in protein and sodium (both of which increase calcium loss)
[2].
While calcium is essential for strong bones, it is not enough.
Muscles aren't the only things that get stronger when you train
with weights. Bones get stronger too [3]. Think of bones as a growing
organ. They respond to stress just as muscle does.
Unfortunately, many weight-training
routines designed for women (light weights with high repetitions)
simply don't impose enough stress on bone to stimulate remodeling.
Women, who have a greater risk of osteoporosis than men, need to
meet the minimal essential strain required for bone remodeling to
occur. Bone growth is proportional to the degree of stress imposed
upon it. The greater the overload — within certain limits,
of course — the greater the growth [4].
A suitable workout routine designed for women
who want to get strong, lean, and fit while staying attractive and
feminine is available elsewhere on this site.
The bottom line is that the link between the various nutrients
in the diet and bone health is a very complex one. High protein
diets themselves are not the problem. Many nutrients interact, not
only among themselves, but with other genetic and environmental
factors. More information on what to
eat to protect your bones is available elsewhere on this site.
Related Articles
References
1. Wengreen, H.J., Munger, R.G., Cutler, D.R., Corcoran, C.D., Zhang,
J., & Sassano, N.E. (2004). Dietary protein intake and risk
of osteoporotic hip fracture in elderly residents of Utah. Journal
of Bone and Mineral Research, 19, 537-545
2. Weinsier, R.L., & Krumdieck, C.L. (2000). Dairy foods and
bone health: examination of the evidence. American
Journal of Clinical Nutrition, 72, 681-689
3. Umemura, Y., Sogo, N., & Honda, A. (2002). Effects of intervals
between jumps or bouts on osteogenic response to loading. Journal
of Applied Physiology, 93, 1345-1348
4. Cussler, E.C., Lohman, T.G., Going, S.B., Houtkooper, L.B., Metcalfe,
L.L., Flint-Wagner, H.G., Harris, R.B., & Teixeira, P.J. (2003).
Weight lifted in strength training predicts bone change in postmenopausal
women. Medicine
and Science in Sports and Exercise, 35, 10-17
5. Roughead, Z.K., Johnson, L.K., Lykken, G.I., & Hunt, J.R.
(2003). Controlled high meat diets do not affect calcium retention
or indices of bone status in healthy postmenopausal women. Journal
of Nutrition, 133, 1020-1026
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