Does vegetarianism make you dumber?

http://www.psychologytoday.com/blog/you-illuminated/201102/does-vegetarianism-make-you-dumber
This past year, David Benton, a psychology professor in Wales who studies the relationship between diet and behavior, examined the memory of vegetarians and omnivores before and after taking either placebo or creatine supplements.  Prior to taking pills, vegetarians and omnivores performed similarly on a memory test.  Both the vegetarians and omnivores were divided into two groups, one receiving placebo, the other creatine.  After a week, the omnivores scored the same whether or not they had taken placebo or creatine, and the vegetarians who had taken placebo still matched the omnivores' performance.  However, the vegetarians who took creatine leapt ahead.   Initially, all groups were roughly even, but the creatine-enriched vegetarians now had better memories.