The power adapter handles voltages up to 240 V, so you'll be fine.
Electrical and operating requirements
Line voltage: 100V to 240V AC
Frequency: 50Hz to 60Hz
Operating temperature: 50° to 95° F
(10° to 35° C)
Storage temperature: -13° to 113° F
(-24° to 45° C)
Relative humidity: 0% to 90% noncondensing
Maximum operating altitude: 10,000 feet
Maximum storage altitude: 15,000 feet
Maximum shipping altitude: 35,000 feet
from
http://www.apple.com/macbook/specs.html