Study
suggests a much earlier onset for bone problems
Monday, April 26, 2010
We all know that eating a calcium-rich diet is important for
keeping our bones healthy and strong. This concept is clearly on
display in any elementary school cafeteria where the walls are
decorated with colorful posters with celebrity icons encouraging
children to make sure they drink milk every day. However, emerging
research suggests that urging school-aged children to pay attention
to their dairy intake might actually be too late to optimize their
bone health. Indeed, the idea that long-term bone health may be
"programmed" or established during infancy or even earlier is
gaining significant scientific support as nutrition researchers
continue to study the genesis of chronic diseases such as
osteoporosis.
In a presentation concerning early nutritional programming and
long-term skeletal health to be presented on April 27 at the
Experimental Biology 2010 meeting in Anaheim, researchers from
North Carolina State University and the US Army Research Institute
of Environmental Medicine will present evidence that very early
calcium nutrition may have more impact than we previously thought.
This presentation is part of the scientific program of the American
Society for Nutrition, home of the world's leading nutrition
researchers.
The research is led by Dr. Chad Stahl, an Associate Professor in
the Department of Animal Science at North Carolina State
University, who studies the nutritional regulation of growth and
development and utilizes the neonatal pig as a surrogate for the
human infant. Stahl and his colleagues have a long-standing
interest in understanding how much calcium babies need in order to
optimize bone density and strength when they get older. Not only is
this a worthy academic question, but it has special relevance to
the infant food industry which currently fortifies most baby
formulas with calcium at levels substantially above those found in
breastmilk – considered the "gold standard" for infant nutrition.
This differential level of fortification has been based largely on
older studies suggesting that breastmilk's calcium is substantially
more usable than that in baby formulas. However, more recent
research has challenged this dogma, and Dr. Stahl and his group are
committed to helping determine what is best in this
regard.
To test their hypotheses, the scientists bottle-fed 12 piglets a
calcium-rich diet and another 12 piglets a calcium-deficient diet
during the first 18 days of life. Throughout the study, blood
samples were drawn frequently from the piglets, and they were
weighed daily. At the end of the study, the researchers collected
samples from the animals' bone marrow, livers, kidneys, and small
intestines. They also tested their hind legs for bone density and
strength.
Their results were both surprising and intriguing. For instance,
there were no differences between groups in terms of blood markers
of calcium status and growth. These data support the previously
suggested concept that, unlike what happens in adults, calcium
absorption in newborns is not dependent on vitamin D. They also
documented marked differences in bone density and strength such
that the calcium-deficient piglets were compromised. When they
looked at the bone marrow tissue which contains all the material
(known as mesenchymal stem cells) that will eventually become
bone-forming cells, they discovered that many of the
calcium-deficient piglets' cells appeared to have already been
programmed to become fat cells instead of bone-forming osteoblast
cells. Fewer osteoblasts in early life may translate to a
diminished ability for bones to grow and repair themselves
throughout the remainder of life. Thus, it appeared as if calcium
deficiency had predisposed the animals to having bones that
contained more fat and less mineral.
Dr. Stahl concluded that "While the importance of calcium nutrition
throughout childhood and adolescence is well recognized, our work
suggests that calcium nutrition of the neonate may be of greater
importance to life-long bone health due to its programming effects
on mesenchymal stem cells. It also points to a potential paradigm
shift in which health professionals might want to begin thinking
about osteoporosis not so much as a disease of the elderly, but
instead as a pediatric disease with later onset."
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Federation of American Societies for Experimental Biology
Thanks to Federation of American Societies for Experimental
Biology for this article