Some more thoughts about bone marrow. People are pushing fish oils with n3 fatty acids for brain function and even to cure mental illness. It is not the lack of any specific fatty acids that causes mental problems. They are caused by endogenous and exogenous toxins. Impaired fat metabolism is a consequence, not a cause of brain dysfunction. Fatty acids, both n3 and n6 are important in the brain. I'm not going to worry so much about the fat content of marrow if I have eat it from grain fed animals, but more about whether they have had antibiotics, etc. My best, Ellie