https://www.ncbi.nlm.nih.gov/m/pubmed/28040519/
"We found no evidence that following a vegetarian diet, semi-vegetarian diet or a pesco-vegetarian diet has an independent protective effect on all-cause mortality."
Prev Med. 2017 Apr;97:1-7. doi: 10.1016/j.ypmed.2016.12.044. Epub 2016 Dec 29.