It's logical really; everyone needs iron, the vegetarians just need to get it in other forms such as vitamin pills or iron suppliments. The iron from a meat-eater's diet is based naturally and has already been broken down within a body, so therefore it's much stronger and improves vitality/strength. The benefits of this allow meat-eaters to live longer while vegetarians stick to a healthier diet, however, it isn't healthy overall, as most lack in iron, as I previously stated. That seems to be the only downside of being a vegetarian, while ethically, being a meat-eater causes many other issues based on your judgements/opinions of the world around you. So yes, meat-eaters rightfully live longer.
... did I just sound like an advertisement? :x