Jack writes:
Everyone is right.  Dark skin is a risk factor for rickets if we are
depending on ultraviolet exposure for vitamin D intake.  But why is dark
skin not a risk factor for rickets in the baby?  Because he gets stores
of vitamin D from the mother during pregnancy.


I guess I've never thought about it terms of breastfeeding (must be a FIRST
for me) -- but we usually see rickets in children of 4-10 years, who
probably are not breastfeeding any more.  For how long can prenatal stores
supply the vitamin D needed to a young child if he is breastfed for say 6
months?  And if he has dark skin and lives in Toronto (WAY FAR NORTH
relative to Texas, Jack!), then perhaps he is at risk?  Do you know how long
the prenatal stores last?

Katherine A. Dettwyler, Ph.D.
Associate Professor of Anthropology and Nutrition
Texas A&M University