When you’re in need of a little natural energy boost, do you reach for the B12? Dubbed the “energy nutrient” because of the role it plays in cellular metabolism, vitamin B12 can be found in all sorts of energy drinks and bars. However, this essential vitamin’s most important claim to fame may not lie in its ability to energize, but in its power to protect your brain. 

Researchers are finding that enhancing blood levels of vitamin B12 may help keep your brain firing on all cylinders, especially as you age. A study that appeared in the January 2012 online edition of the American Journal of Clinical Nutrition reported that supplementing with a combination of B12 and folic acid (another B vitamin often taken with B12) for two years improved both immediate and delayed memory in a group of seniors. 

This isn’t the first time researchers have observed a relationship between B12 status and the brain. An Oxford University study published in the journal Neurology in September 2008 suggested that seniors with the highest levels of vitamin B12 were six times less likely to exhibit brain atrophy than those in the study whose B12 levels were lower. 

On the flip side, scientists have linked low blood levels of this important nutrient to cognitive decline, depression and even brain shrinkage. A new report in the July 2012 issue of the Journal of the American Geriatric Society found a direct connection between low blood levels of this water-soluble nutrient and poor brain function. The survey, which involved 549 elderly men and women taking part in the well-known Framingham Heart Study, also noted that the less B12 people had in their bloodstream, the faster the brain decline. In fact, the researchers noted that cognition in those with the lowest concentrations of serum B12 declined four times faster than in those whose levels were normal. 

What is it about B12 that makes it so essential to your grey matter? One leading theory is that it helps ensure healthy blood flow to the brain. Along with folic acid and vitamin B6, B12 helps prevent elevated levels of homocysteine—a byproduct of the normal breakdown of the essential amino acid methionine. Although the body can use small amounts of homocysteine, high levels irritate the inner lining of blood vessels and encourage the development of atherosclerosis, commonly known as clogged arteries. This slows blood flow throughout the entire body, including the brain.

The brain-damaging effects of homocysteine were recently shown in a study of 121 people taking part in the Chicago Health and Aging Project that appeared in the September 27, 2011 issue of Neurology. That investigation revealed that people with a B12 deficiency not only had higher homocysteine levels, they also had consistently poorer cognitive test scores. And MRI scans showed a measurable decrease in their brain volume.

Beyond the brain

Of course, B12’s benefits aren’t just limited to your brain. It’s also an essential nutrient for a healthy heart due to its ability to keep homocysteine levels in check. Preliminary research at the University of California, San Francisco, which was presented in the March 2004 issue of the Journal of Clinical Endocrinology and Metabolism, also suggests that this essential vitamin may help prevent fractures in elderly women. Plus there is some speculation by researchers at Brigham and Women's Hospital and Harvard Medical School that the homocysteine-lowering effects of vitamin B12 (combined with vitamin B6) may help keep macular degeneration at bay, based on a clinical trial of more than 5,400 women that appeared in the February 23, 2009 issue of Archives of Internal Medicine.

Are you getting enough?

Foods such as beef, fish, chicken and eggs are the best sources of B12, making it hard for vegetarians and vegans to obtain adequate amounts from the foods they eat. But even if your diet does include plenty of B12-rich foods, you may still find yourself shortchanged as you age. According to a February 2009 article in the American Journal of Clinical Nutrition, one in five people over the age of 60 suffer from gastric atrophy or a thinning of the stomach lining. This condition reduces the amount of B12 that’s absorbed by the small intestine. Another problem is that, without ample digestive juices and enzymes—specifically hydrochloric acid and gastric protease, which often are in short supply in those over 50 and in those taking proton pump inhibitors—your body simply can’t pull B12 from the foods you eat. 

Most people who have trouble absorbing B12 can effectively boost their levels with supplements. Taking sublingual vitamin B12, which is absorbed by the blood vessels in the mouth, is often better for seniors who may have trouble absorbing the vitamin through the stomach. Vegetarians and others without absorption issues can get their B12 as part of a B-complex supplement that provides a full spectrum of B vitamins.