Oral synthetic folic acid and vitamin B12 supplements work--if one consumes them.
Oral supplements of synthetic folic acid and vitamin B12 are very effective in increasing blood levels of the vitamins and are known to prevent birth defects and cardiovascular diseases.
Oakley
Godfrey P
GP
Rollins School of Public Health of Emory University, Atlanta, GA 30322, USA.
D002318:Cardiovascular Diseases / Q000517:prevention & control; D000013:Congenital Abnormalities / Q000517:prevention & control; D019587:Dietary Supplements; D005492:Folic Acid / Q000008:administration & dosage*; D006801:Humans; D014805:Vitamin B 12 / Q000008:administration & dosage*
D005492:Folic Acid; D014805:Vitamin B 12