[Margarine] decreases immune response.
truthorfiction.com (no link - I'm not sure if the site is safe for Windows OSes) gives more detail and says that it is true
- Margarine decreases immune response-Truth! We found several references to this including an article by nutritionist Dr. Mary Enig that said that consuming trans fatty acids "Affects immune response by lowering effeciency of B cell response and increasing proliferation of T cells."
Wikipedia describes Mary Enig as a nutritionist and that "She has promoted skepticism towards the widely held view in the medical community that high saturated fat diets lead to heart disease".
I've heard from Ben Goldacre's book Bad Science that many nutrionists promote pseudoscientific theories.
As the claim in the viral email is a bit terse, I'll ask about the claim in the truthorfiction.com page: does eating trans fatty acids affect the immune response of humans?