Here's some food for thought: Researchers in New Zealand are studying whether eating butter instead of margarine can help to reduce the risk of allergies and asthma. They are currently recruiting children to take part in a study examining the effects of butter and an enriched butter made from cows fed fish oil on eczema.
Read about the study here: http://www.nzherald.co.nz/health/news/article.cfm?c_id=204&objectid=10585257
Apparently, you don't need to eat a stick of the stuff to obtain benefit- 10grams (just a few pats) may do the trick!
Just wait until this gets out- my dad (who refuses to even touch anything that's not "real butter" because it "just doesn't taste right") and father-in-law (who forwards me emails about how margarine is "one molecule away from plastic") are going to be thrilled.