There is also some vitamin C in meat. Not much, but it's there and there is enough of it if you don't eat carbs. It makes sense why we lost the ability to produce vitamin C: If you eat just meat, you don't need it, or get enough of it from meat alone. If you eat carbs, you ingest vitamin C along with carbs. In neither case do you need to produce it. It's like the abysmal carps losing their eyes over thousands of generations because they have no need for them. Vitamin C only becomes a problem if you eat a very unhealthy diet high in highly processed foods such as pasta and nothing else.