Why can't the Dalai Lama be a vegetarian?

In this answer to 'Are all Buddhists vegetarian? ' the poster says > [the Dalai Lama] has a medical condition that disallows > him to be a strict vegetarian. I've heard this before and never questioned it. But thinking about it - what kind of medical condition would preclude the Dalai Lama from being a vegetarian. Suddenly I feel very skeptical that there is any such condition. Is that unfair?