Fwd: FW: link for cobalt levels following mB12 injections, autism cohort

[Guest guest]

From: BADILLO9@... Sent: Tuesday, May 04, 2010 5:54 AMTo: drdavid@...Subject: Re: FW: link for cobalt levels following mB12 injections, autism cohort

To the editor:While I have a great deal of respect for the overall work of and MarkGeier, their recent article “An Autism Cohort Study of Cobalt LevelsFollowing Vitamin B12 Injections†misuses findings to create an unjustifiedlevel of fear about the use of methylcobalamin (methylB12) to treat autism.Since this treatment is widely recognized as being effective in asignificant number of autistic individuals, it is critical to not allow ascientifically flawed paper to undermine its use. The authors found a meanplasma level of cobalt of 0.82 ug/liter for subjects receiving methylB12injections, which corresponds to a concentration of 14 nM, and they foundthat neuroblastoma cells exhibit a toxic response to cobalt(II)nitratehexahydrate with an LC50 of 559 uM. As a first significant problem, theircomparison of cobalt in vitamin B12 with the free heavy metal form of cobaltis an inappropriate and misleading comparison. It would be as if supplementscontaining vitamin B12 actually contained the heavy metal cobalt, which isobviously not the case. The authors have an obligation to characterize thechemical form of cobalt, which is highly likely to be overwhelmingly in theform of vitamin B12, not in the form of free cobalt. Secondly, thedifference between the plasma concentration and the toxic concentration is40,000-fold, but the authors fail to make this comparison. If indeed theplasma form of cobalt is in the form of vitamin B12, the difference in freecobalt concentrations is actually much higher than 40,000-fold. Thesediscrepancies make this article scientifically invalid and as such it shouldbe withdrawn. Studies directed toward identifying optimal dosing regimensfor methylB12, with minimal toxicity, are indeed important. Unfortunately,this is not such a study. Sincerely, C. Deth, PhDProfessor of PharmacologyNortheastern University360 Huntington AvenueBoston, MA 02115USA