"I'm all for vegetables. I believe most of our calories should come from vegetables. None the less, if you are a vegetarian or vegan, you've got to keep in mind that you are going to be missing key nutrients. Unless, you go out of your way to get them. ...Vitamin b12 is only found in animal foods, but it's not really made by animals. Bacteria, which are neither animal nor plant, make vitamin b12."
"...If you're only eating vegetables, it's very likely you're going to be deficient in Vitamin B12. Vitamin B12 is important for nerves, it's important for blood. It's an incredibly important vitamin. In fact, Vitamin B12 is the most potent of all the vitamins. It's the only vitamin that is dosed in these tiny "micro-gram" doses."
"...Our gut bacteria makes some Vitamin B12, but because Vitamin B12 is absorbed in the small intestine, by the time the bacteria make it, it's downstream from where the absorption takes place."
"...So the best way to get Vitamin B12 is from your food. If you're a vegetarian, then your stuck with supplementing or you can use fortified nutritional yeast. ...There's another really good source for Vitamin B12 for vegetarians, this is one that all vegetarians should be eating, and that's seaweed, specifically Nori seaweed."