Effects of different levels of caffeine supplemented to the maternal diet on the brains of newborn rats and their dams.

At birth, dams with 8 randomly assigned pups were divided into three groups. Dams of group 1 were fed a control diet. Dams of groups 2 and 3 were fed the control diet supplemented with caffeine (1 mg and 2 mg/100 g body weight, respectively). Pups were killed at day 15 and their brains removed. After weighing, brains were analyzed for DNA, protein, cholesterol, zinc and alkaline phosphatase activity. Brain and plasma caffeine levels were also determined on groups 2 and 3. The dams were milked to measure caffeine levels. The brains from the dams were analyzed for the same parameters as the pups. Caffeine levels in group 3 were consistently higher than in group 2. In the pups, body and brain weights were heavier in group 3 than in the controls. Protein and cholesterol concentrations in group 2 were less than either controls or group 3. Alkaline phosphatase activity in group 2 was higher than either controls or group 3. In the dams, DNA concentration in groups 2 and 3 was less than the controls. Protein and cholesterol concentration in group 2 was less than group 3. It was concluded that low levels of caffeine in the maternal diet during lactation could affect various parameters in the newborn brain. These effects were different from those when the dietary caffeine level was doubled. In contrast, the effects of caffeine on brains of the dams were relatively minor.