AAN.com - Vitamin B12, a nutrient found in meat, fish and milk, may protect against brain volume loss in older people, according to a study published in the September 9, 2008 issue of Neurology®, the medical journal of the American Academy of Neurology.

For the study, 107 people between the ages of 61 and 87 underwent brain scans, memory testing and physical exams. Researchers also collected blood samples to check vitamin B12 levels. Brain scans and memory tests were also performed again five years later.

The study found that people who had higher vitamin B12 levels were six times less likely to experience brain shrinkage compared with those who had lower levels of the vitamin in their blood. None of the people in the study had vitamin B12 deficiency.

“Many factors that affect brain health are thought to be out of our control, but this study suggests that simply adjusting our diets to consume more vitamin B12 through eating meat, fish, fortified cereals or milk may be something we can easily adjust to prevent brain shrinkage and so perhaps save our memory,” said study author Anna Vogiatzoglou, MSc, with the University of Oxford in the United Kingdom. “Research shows that vitamin B12 deficiency is a public health problem, especially among the elderly, so more vitamin B12 intake could help reverse this problem. Without carrying out a clinical trial, we acknowledge that it is still not known whether B12 supplementation would actually make a difference in elderly persons at risk for brain shrinkage.”

“Previous research on the vitamin has had mixed results and few studies have been done specifically with brain scans in elderly populations. We tested for vitamin B12 levels in a unique, more accurate way by looking at two certain markers for it in the blood,” said Vogiatzoglou.

Vogiatzoglou says the study did not look at whether taking vitamin B12 supplements would have the same effect on memory.

Editorial note - This study should prompt all older patients to ask their primary care provider about the exact number value of their vitamin B12 level and not simply accept the doctor’s interpretation of the test as “OK” or “normal” or “fine.” Many old-school doctors will see a B12 level in the 250 to 350 range and tell you that your vitamin B12 level is adequate, but those numbers are at the bottom of a wide “normal” range that pushes well up towards 1000. And remember that that “normal” range is established typically by a bell curve distribution of the B12 levels of the general population (many of whom have quite poor dietary habits). A B12 level closer to the top of the so-called normal range would probably be better for your health, and may provide the “anti-aging” brain benefit pointed to in this study.

Having an inadequate vitamin B12 level is almost inexcusable in the 21st century. Routine vitamin B12 supplements (including the B12 found in multivitamins) are very inexpensive and nontoxic, and even if one has B12 malabsorption problems, studies have found that simple sublingual (tablets that dissolve under the tongue) vitamin B12 supplements produce B12 levels in the blood comparable to B12 shots (injections). In addition, (fasting) vitamin B12 blood levels can be obtained easily and routinely, and can be added to one’s lipid and fasting blood sugar lab studies. Vegetarians and vegans, heavy alcohol users, or those with gastritis or who have had certain kinds of intestinal or bypass surgery are at much higher risk of B12 deficiency than the general population. My favorite vitamin B12 supplement is sublingual methylcobalamin (or “methyl-B12″), which is the most neurologically active form of vitamin B12 - Dr. Z.