hello, actually i wanted to ask question about my elder daughter who is 8 yrs old now. she has very low immunity. she falls sick often and cannot get out of it very easily or fast. what might be the reason for her low immunity? when she was baby, breastmilk was not enough for her, so very early we had to start formula. but since 4th month we stopped even formula and started cow milk for her. can this be the reason for her low immunity? what can be done to increase it?