"However, there is one vitamin, called vitamin B12, which does present a
genuine nutritional issue, although one that is easily solved.

When vitamin B12, which is produced by bacteria and other one-celled
organisms in the small intestines of animals, is made by humans, it is not
well absorbed and retained. Found mainly in animal products, small amounts
may be found in plant products due to bacterial contamination.1,2.

Correction it is the waste fecal product of those bacteria found in the
large not small gut. It is found in some plant foods because they are
contaminated with animal feces, including human, containing those bacteria.

Some indians who came to n. america were seen developing symptoms of not
getting enough vitamin b12. It was soon learned that rules controlling how
much animal fecal matter and animal parts could be in grain and other such
plant products were far more loosse and often ignored in india.

In n. america they were no longer eating those animal products and fecal
matter and thus the cause of not getting enough vitamin b12. Using
synthetic vitamin b12 pills solved their health problem.