Caffeine consumption has been implicated in the development of cardiovascul
ar disease. Therefore, in the present study, litters of rats were combined
upon birth, and 8 pups were randomly assigned to each dam. Dams with pups w
ere divided into 2 groups: group 1 received a 20% protein diet as a control
, and group 2 received the 20% protein diet supplemented with caffeine (4 m
g/100 g body weight). Pups from both groups were killed on days 11 and 15.
Transmission electron microscopy revealed swollen, disrupted, degenerating
mitochondria and intracellular edema in the hearts of rats in the caffeine
groups when compared with those of the controls. Plasma Cu concentration wa
s significantly decreased. These results indicate that early exposure to ca
ffeine through maternal milk adversely affects cardiac mitochondria of rat
pups and may be associated with decreased plasma Cu levels. It is unclear w
hether these results apply to the human infant. Interspecies extrapolation
from rat to human must be made with caution.