Sometimes we get some really interesting contributions.  This one confirms that Vitamin B12 is important for immune systems by describing the immune systems of badgers and cows.

And it's published by a fairly reputable source - UK Parliament.

The important information on Vitamin B12 is in section 7, which is about 8 pages into the report (use the right hand scroll bar to scroll down).  It says in essence that we could avoid a badger cull if we increase the level of B12 in both badgers and cattle by increasing the amount of available cobalt (which is needed to manufacture B12 in the animal gut).  This would mean that both animals were able to resist bovine tuberculosis (bovine TB). So B12 can save a life!

Thanks Norman!

7.  COBALT DEFICIENCY AND THE IMMUNE SYSTEM

  Cobalt deficiency is particularly acute on soils where it is deficient in the parent rock, such as granite, and on limestone soils where the raised pH may make both cobalt and zinc less available. Optimum levels of available cobalt are 1.8-3.0 ppm.

  Adequate cobalt ie vitamin B12 levels have powerful effects on the immune system, particularly in the ruminant. (i) B12 can help suppress internal parasites and a number of infections. Goodwin-Jones finds a response to cobalt in lower worm counts, and prevention or clearance of diseases such as orf and infectious keratitis (New Forest). (ii) As the cofactor of methyl malonyl CoA mutase in the propionate pahway for the synthesis of liver glucose, it is crucial to ruminant energy metabolism, and thus indirectly of immune function. (iii) As cofactor of 5-methyl tetrahydrofolate homocysteine transferase, it catalyses the reconversion of homocysteine to methionine with recycling of S-adenosyl methionine (SAM), the methyl donor on which all cellular methylation reactions depend eg for transmitter synthesis and degradation; for degradation of histamine, cell metabolites and xenobiotics; for fatty acid transport and membrane synthesis; and for regulation of gene expression, including the rapid requirements for gene expression in the immune system and its cytokine network.