Too Much of a Good Thing: Excess vitamin A may hike bone-fracture rate
By Nathan Seppa
Dietary studies have suggested that people who consume large amounts of vitamin A in foods, multivitamins, or both are more likely to suffer hip fractures than are people who ingest modest amounts.
New evidence bolsters these findings. Researchers have now correlated men’s blood concentrations of vitamin A with a later incidence of broken bones–a comparison that avoids the vagaries that plague diet-recall studies.
Taken together, the new work and the diet studies raise knotty questions about the maximum amount of vitamin A that a person can safely ingest each day, says study coauthor Karl Michaëlsson, an orthopedic surgeon at University Hospital in Uppsala, Sweden. He and his colleagues report the new findings in the Jan. 23 New England Journal of Medicine.