Vitamins A, D, E, and K are all fat soluble, we NEED to eat fat with foods that have these vitamins or else we're missing out on absorbing all these vitamins. (part of why so many ppl are nutrient deficient- bc they've taken all the fat out of their food!) Carrots for example are high in vitamin A (beta carotene) and our livers becomed taxed... they are working so hard to excrete enymes to absorb only some of the vitamins, if there is no fat for the vitamins to bind with to make it into our blood. Butter, you could say, is an 'activator' to utilize these vitamins It makes sense to "butter your carrots" There is a reason it tastes soo good together.
I eat lots of butter from grass fed cows. It is high in CLA and omega-3's. Butter from feedlot animals is best used spraingly because toxins, pesticides, fertilizer or toxic byproducts from a poorly fed diet, are all stored in the fat of an animal or the fat outputs. It would make sense to avoid the fat from feedlot animals because they can be full of these disease-causing toxins. Grass-fed butter is high in good fatty-acids stored in the fat that help prevent disease (a long with plenty of vitamins too, this is why grass fed butter appears much more yellow and bright than other butter, I didn't know this until recently). Isn't it odd how the same output from the same animal can be completely different based on what the animal ate and how it was raised?
Don't eat margarine (talk about toxic...) Eat real butter.