By Brendan Moyle 01/04/2016

The short answer. No.

Longer answer:

Newspapers are fond of stories that breathlessly announce discoveries as revolutionary.  Fossils never add anything to our knowledge incrementally.  They will always rewrite the theory of evolution.  Cancer is another popular target for revolutionary new treatments or causes.  So it was with some skepticism I read that, quote, “Scientists have found vegetarianism can cause a genetic mutation that can lead to cancer”.  This appeared in the NZ Herald yesterday, and was originally from the Daily Telegraph.

I found the original scientific paper without much difficulty from the journal’s website.  It mentions cancer a grand total of three times in the paper, and does not demonstrate any link to the mutation they studied.  The paper was not in fact, attempting to demonstrate any empirical link to cancer.  It was not a paper on cancer or heart disease.

What the authors were interested in, is the synthesis of Long Chain Polyunsaturated Fatty Acids (LCPUFAs). We can get it directly by eating animals, or by synthesising it ourselves.  This is done via the FADS2 gene, which makes the required enzyme.  Some of us have an insertion-mutation in this gene.  Some of us have a deletion-mutation.  The insertion-mutation is more common in Indian vegetarians (68%) than Americans (18%).

The reason is that the insertion-mutation has been selected for in vegetarian populations.  Lacking an animal source for LCPUFAs, those who had the mutation coped with a vegetarian diet better.  That is, they lived longer and had more offspring than those that didn’t.  This is not what a “long term health risk” looks like.

In no sense does being vegetarian cause this mutation.  It’s in all human populations.  You won’t acquire it by becoming a vegetarian.  You won’t get cancer by becoming a vegetarian.  The possible (not demonstrated) pathway is that if you consume a high quantity of vegetable oil- especially seed oils- you end up with a little more arachidonic acid.  Which could be bad for you. Or maybe not.