Journal Club:  Vegetarians and Heart Disease
Channel: C0nc0rdance
Date: 19/08/2011

The article is:
Am J Clin Nutr. 1999 Sep;70(3 Suppl):516S-524S.
PubMed Entry:  http://www.ncbi.nlm.nih.gov/pubmed/10479225
FREE FULL TEXT:  http://www.ajcn.org/cgi/pmidlookup?view=long&pmid=10479225
FREE PDF File download  http://www.ajcn.org/content/70/3/516S.full.pdf+html

This is the only critical review of large population prospective studies comparing vegetarians to non-vegetarians.  As such, it remains the best arbiter of what the actual benefits are of these diets.

Vegetarians in these studies had a lower risk of heart disease.  Other than that, it wasn't possible to demonstrate any other effects using this study.

The major criticism of this type of systematic review is the mixing of different (heterogenous) data sets.  It's hard to compare vegans in 1970's Germany to 1990's Seventh Day Adventists and not get some confounders.