Low Vitamin B12 status strongly tied to mental decline in agingadults

November 13, 2007

Individual amino acids combine to create different proteins and proteins are the building blocks of your body. One of the essential amino acids you obtain when you eat any protein is methionine and methionine is necessary to life; it is found in meat, fish, and dairy, and to a lesser degree in fruits and vegetables.

One of the many pathways that methionine enters into is its conversion to Cysteine; an amino acid necessary for the formation of tissues and detoxification of dangerous chemicals. If you lack the B-complex vitamins Folic Acid, B12, and B6, you will not convert methionine efficiently into Cysteine and instead you will suffer with rising levels of an intermediary known as Homocysteine; Homocysteine is very unstable and if found at too high a level is dangerous. An elevation in your blood level of Homocysteine increases the rate of blood vessel clogging and also increases your risk of stroke and heart attack. Elevated homocysteine is also connected to hip fracture after a stroke, and to depression and mental deterioration.

The purpose of this study was to evaluate the risk of mental decline in relation to levels of B12 or Folic Acid. In their study, researchers from Oxford University in the UK and Trinity College in Dublin, Ireland, investigated the level of homocysteine and other markers of vitamin status at 3 junctures over a 10-year period and compared them to levels of Vitamin B12 and Folic Acid while also giving the study subjects a test to evaluate mental status in a total of 1,648 participants. Brain function declined abruptly at younger ages in some participants but remained intact in others until very old age. The scientists looked at levels of holotranscobalamin in the subjects; this level increases as Vitamin B12 status improves. They also looked at the levels of homocysteine (this increases as levels of both folic acid and B12 decrease) and methylmalonic acid (this increases with a decrease in the body's B12 reserve). Having a lowered level of holotranscobalamin and elevated levels of both homocysteine and methylmalonic acid predicted a decline in cognitive function. If the level of holotranscobalamin, a sensitive marker of sufficient B12, doubled, this indicated a 30% slower rate of cognitive decline. A doubling of homocysteine or methylmalonic acid was disastrous, indicating a 50% or greater respectively more rapid cognitive decline; all of this indicates that it is a lower level of Vitamin B12 that is more important for the loss of mental function with aging. The message is to get adequate B12 and also Folic Acid to protect your mental function. The study is published in the November 2007 issue of the American Journal of Clinical Nutrition.