Over the years we’ve had a lot of coverage on Alzheimer’s disease and on supplements and foods that can help prevent memory loss. Check out, "The B’s are anti-Alzheimer’s" and "Sustain your brain."

Research has shown that a complex B vitamin improves brain health, but the new focus is specifically on B12. According to a study that came out last week Vitamin B12 may protect against brain shrinkage. Vitamin B12, which is known to be helpful for nerve-tissue metabolism and with maintaining healthy nerve cells and red blood cells, is found in food of animal origin, such as meat, fish, eggs and dairy. B12 can also be taken as a supplement and in fortified foods.

The B12 study from the University of Oxford, found that people with high levels of B12 in their blood were six times less likely to experience brain shrinkage and to develop dementia. The study followed 107 community volunteers between ages 61-87 for five years. Researchers took blood samples to record B12 levels and calculated brain volume loss with MRI scans. They found that there was a greater decrease in brain volume among the people with lower B12 levels. These findings suggest that brain function can be improved by adjusting your diet. Anna Vogiatzoglou, lead author of the study, said it’s still not known if B12 supplementation can actually make a difference in brain shrinkage for the elderly.

Brain shrinkage is usually associated with dementia and the development of Alzheimer’s disease. The disease affects over 13 million people worldwide. According to the article, "Low folate levels may increase dementia risk: study," by the year 2047 people affected with Alzheimer’s disease is expected to quadruple.

Another study, from the article "Genetics may influence B12 absorption, says study," mentions that genetic variations may interfere with the absorption of vitamin B12 into your body. The article says that up to 25 percent of the elderly may be B12 deficient and vegans and vegetarians are at risk. Harvard researchers identified FUT2, the gene associated with a person’s ability to digest and absorb B12, in a genome-wide scan of 1,658 women of European ancestry. Out of 528,000 genetic variants FUT2 was shown to have the greatest effect on B12 levels. Although it's important to note that there is no direct results that show people with this gene variant suffer from any cognitive affects associated with low B12 levels. More studies are still needed to clarify this finding.

Check out the Office of dietary supplement B12 fact sheet to find the levels of B12 in food products. Foods that are high in B12 include red meat, with the highest in organ meats, such as liver and kidney, fish and seafood, such as trout, salmon, clams and mollusks and dairy products, such as yogurt and milk. There are also some B12 fortified cereals that are a good source for vegetarians. There is research that suggests B12 can be found in some plant sources including fermented soy products, seaweeds and algae, but the consensus is that they are not reliable as a source of B12 as noted on the Vegetarian Society’s information sheet.