All of the sudden my LO started to refuse bottle with my expressed BM. We've been giving her bottle from 6 weeks to get her ready for the time I'm going back to work, she is now 11 weeks. I taisted the milk and it was rancid. I figured it was lipase as scalding helped to keep it. It is interesting though my frozen supply does not have this issue, it started after we all got over some virus- combo of GI and respiratory symptoms. I searched and searched as going back to work (do 12 hr shifts being a nurse) I have limited oportunity to scald the milk, on top of which do not want to loose any BM benefits. Here is what I found - some reseach shows that fish oil increases lipase activity, but in my case - I've been taking it for years and took krill oil all the way through pregnancy and up untill now (this does not seem to be the cause for me as it is not a change and issue just started). Big change which I've noticed was weight loss due to this virus - I suddenly dropped 3lbs, all this time before I was really careful about not having rapid weight loss to minimize any chance of compromizing milk supply/quality. And fat content of my milk noticably dropped too, despite everything reputable resourses say re diet and milk fat (from creamy yellow with thick line on top when separates, it is white with very little cream). The reseach I found is very limited on breast milk, but lipase activity appears to be highly influence by calorie restriction and different tissue reacts different - some by decreased activity(like fat tissue), other by increased activity (muscle) - again no info on breast tissue... The extend of calorie restriction appears to play role as well - looks like moderate restriction increases lipase activity, while severe restriction- decreases(cases of malnutrition and very low oral intake). So... I am on the mission!!! has anybody notice lipase issue after moderate weight loss or do you think there was a connection for you? Did anybody take fish oil ( DHA, EPA, krill oil, etc) and have/ or not lipase issue? Thank you everybody for all the great support and info I had from you in the past, you helped me through some tough BF times and fears!