Veg'N diet and B12 Deficiency - good article

What does it say about a diet in its natural form that cannot provide an important nutirent, B-12, and instead requiring supplementaion? That it is not the ideal diet.
Here is an article from a former follower and teacher of the Hallelujah Diet (vegetarian).

Vegan Diet Deficiencies Injure Baby:
Our Experience with Deficiencies on the Hallelujah Diet

http://chetday.com/hallelujah-diet-baby.htm