My son drank breastmilk, powdered formula, and premixed, and no issued due to that. AS for the slee ing through the night thing, I am not sure how old your daughter is, but some babies sleep through the night at 2 months, while other don't until they are 12+ months. I am assuming since your daughter is on formula still that she is still fairly young, and I would not rush the sleeping through the night thing. My son did not sleep through the night consistently until he was eating protien in his meals. The sleep might come with age or with a dietary change.