Mean changes in symptom scores on the Asthma Control Test ( placebo , @ -LSB- @ % CI , @-@ @ -RSB- vs soy isoflavones , @ -LSB- @ % CI , @-@ @ -RSB- ; positive values indicate a reduction in symptoms ) , number of episodes of poor asthma control ( placebo , @ -LSB- @ % CI , @-@ @ -RSB- vs soy isoflavones , @ -LSB- @ % CI , @-@ @ -RSB- ) , and changes in exhaled nitric oxide ( placebo , -@ ppb -LSB- @ % CI , -@ to -@ ppb -RSB- vs soy isoflavones , @ ppb -LSB- @ % CI , -@ to @ ppb -RSB- ) did not significantly improve more with the soy isoflavone supplement than with placebo .