BBB with MPU6050 and ADXL335

I am working on a project that uses MPU6050 and two ADXL335.
I wish to achieve strict 200 Hz on ADXL335(Which i did) and ~50Hz on MPU6050.
They both work fine seperately but when i run them at a same time,
the ADXL335 sample gets delayed by 10~20 ms whenever i2c performs fifo read on the MPU6050.
I have increased the i2c rate to 400kbs but still have this problem.
Is there a way to speed up i2c, preferably, to eliminate the 10~20ms delay and achieve 200Hz on ADXL335?