Wouldn't it be funny if the meat & dairy industry funded that article - the same way they paid doctors to tell patients about the "Four Food Groups," & the importance of meat & dairy in the diet?"
The problem with B12 is not how much you take in, but how much you absorb & some prescription drugs can deplete B12 from the body. It is synthesized from bacteria.
A friend had Anemia & his doctor told him to eat more beef & chicken. When we'd eat out, he always ordered lots of meat. He got worse & worse, then it became life threatening & he was hospitalized for weeks.
My sister's ex mother-in-law had osteoporosis & whenever I saw her, she was drinking milk. I asked her why she drinks so much milk & she said her doctor told her to because of her osteoporosis. After a few months, she couldn't stand because her back was completely curved.
A vitamin or nutrient deficiency is usually not due to inadequate intake - unless someone is actually starving.