See: Drugs depleting nutrients
[2010 Oct] Metformin causes vitamin B12 deficiency
B12 Deficiency From Drugs
[2010 Sept] 10p pill to beat Alzheimer's disease: Vitamin B halts memory loss in breakthrough British trial The tablets contained extremely high doses of vitamins B6, 9 and 12. ...Professor Smith says he ‘would not hesitate’ to take the cocktail of 20mg of vitamin B6, 0.8mg of vitamin B9, or folate, and 0.5mg of vitamin B12, himself, if he were diagnosed with MCI.
 Vitamin B12 Deficiency in Pregnant Women Linked to Birth Defect
 Vitamin B12 Deficiency is a Common Cause for Chronic Coughing
 Vitamin B12 Deficiency can Look Identical to Alzheimer's Disease
VITAMIN B12 LEVELS AND MERCURY - A LINK WITH MULTIPLE SCLEROSIS AND OTHER DISORDERS
[Media UK, 1996, B12--autism] Children lose clinic of hope
[2009 July] 'Heartburn pills wrecked my life': How antacids can have serious side-effects her problems stemmed from the lack of an everyday vitamin, caused by medicine commonly prescribed for ulcers and heartburn - and that Andrea discovered the problem herself by searching on the internet. Andrea was suffering from pernicious anaemia, because of a deficiency of vitamin B12. This vitamin is essential for producing red blood cells and for maintaining a healthy nervous system, specifically the fatty sheath that protects the nerve cells.