A vegan diet is utter insanity. In nature, vitamin B-12 can be obtained only from animal-based products. Period. All B-12 in nature is manufactured by cobalt-fixing bacteria, and bacterial B-12 works its way up the food chain via ruminants and a variety of other means that all involve symbiosis with, or consumption of, cobalt-fixing bacteria, or consumption of smaller animals that do likewise.
A healthy adult who has eaten animal products all their life will have about a 7-10 year supply of B-12 stored in their liver. Once the stored supply gets used up while on a vegan diet or from pernicious anemia or other absorption syndrome, you’ll die.
Unfortunately, children don’t have this reserve, so feeding a child a vegan diet is criminal negligence as it will lead to death from lack of B-12. Period.
Oh, and those that take an artificial B-12 supplement to make up for the insanity of a vegan diet? Well now, just how natural can a diet be that requires you to consume a substance made in a high tech industrial pharmaceutical facility in order not to die from your oh so wonderfully perfect and “healthy”, “natural” diet?
(BTW, B-12 is FAR different than other vitamins. It’s a gigantic molecule that has a single atom of cobalt at its center, and in nature only bacteria can capture this cobalt from the environment and fix it in organic form. Thus all living animals are dependent for their existence on cobalt-fixing bacteria. Furthermore, because of its size, B-12 can be absorbed only when the gastric parietal cells manufacture a substance called intrinsic factor whose sole purpose is to drag the B-12 molecules through the intestinal lining and into the portal vein. Without intrinsic factor, say as a consequence of pernicious anemia, b-12 cannot be absorbed and a person will eventually die unless they regularly inject with B-12.)
Just out of curiosity, how do vegetarians in India survive without meat? How do they get all their vitamins and nutrients?
B12 actually comes from the soil.