BOSTON, MASSACHUSETTS. The classic presentation of B12 deficiency exhibits potentially serious blood related disturbances as well as neurological and psychiatric problems. A recent study examined the association between B12 and folate status and the decline in scores on the Mini-Mental State Examination (MMSE) in the Framingham Heart Study population. Declines in the MMSE score directly relate to cognitive decline. The researchers examined the decline in the MMSE score over 8 years with special reference to the two lowest quintiles of plasma B12. It was found that cohort members with B12 concentrations between 187 and 257 pmole/L, the second quintile, had an accelerated rate of cognitive decline similar to the first (lowest) quintile. It was also found that having B12 levels in the first or second quintile in conjunction with high plasma folate or supplemental folate use predicts an especially high cognitive decline. However, plasma folate or consuming folic acid was not associated with cognitive decline in participants with B12 levels of 258 or greater. The association between high folate and accelerate decline is not clear since the Framingham cohort data were collected before mandatory fortification. Thus the subjects had low folate intakes. In fact, plasma folate greater than 59 nmol/L was found in only one participant with B12 levels less than 258 pmol/L. Folate deficiency was highly prevalent and high folate intakes were not in fact very high. The authors suggest the persistence of low combined vitamin B status suggests a malabsorption phenomenon.

The authors conclude by highlighting the importance of identifying low B12 status and finding and treating the cause in order to avoid rapid cognitive decline. Mandated folic acid in the diet may eliminate anemia, and with it fatigue, the most obvious manifestation of B12 deficiency in the elderly, thus allowing the deficiency to go undetected (the so-called masking effect).

Morris MS, Selhub J, Jacques PF. Vitamin B-12 and folate status in relation to decline in scores on the mini-mental state examination in the Framingham heart study. J Am Geriatr Soc 2012 August;60(8):1457-64