The acousto-optic modulation of fiber Bragg gratings in a four holes suspended core fiber is experimentally demonstrated. Strong modulations with a reflectivity amplitude decrease by up to 67% and a 57% bandwidth increase in the Bragg resonance are obtained for gratings of 0.26 and 1 nm 3-dB bandwidths, respectively. The reduction of the required acoustic power for achieving the acoustooptic modulation compared to conventional solid core single mode fibers points out to more efficient modulator devices in suspended core fibers.