There is a study, published in the prestigious journal Neurology, where M.R.I. scans were used to measure brain volume and blood tests to record vitamin B12 levels.

They divided the subjects into three groups, based on their level of the vitamin, and followed them for five years with annual scans and physical and mental examinations.

The group with the lowest levels of vitamin B12 lost twice as much brain volume as those with the highest levels. The difference was significant, even after controlling for initial brain size, age, sex, education, cognitive test scores and various measures of blood chemistry.

What it does:

Vitamin B12 is crucial to brain function and the overall health of  your nervous system. It’s the engine behind your body’s ability  to make blood. Every cell in your body uses it to convert fuel into energy.    It’s also the key to DNA synthesis and regulation, and enables your body to produce life-giving fatty acids.*

Deficiency signs:
Anemia
Fatigue
Poor nerve function
Diarrhea
Memory loss

Here’s another thing about B12: it powerfully lowers levels of homocysteine, one of the key indicators for heart health.*

That’s because — at high enough levels —   homocysteine provokes an inflammatory response across every system in your body, blood vessels included.

In the past, medicine has completely overlooked this key factor in heart health, focusing instead on cholesterol. That’s a real shame, because the fact is that homocysteine’s the real culprit. And its consequences are entirely preventable.

In fact, all folks really need to keep homocysteine levels in check is to get about 500 mcg of B12 per day.

Sources:

Lean meats—particularly grass-fed beef—and organ meats are a great source of B12. Here’s a list of other good sources:

Clams, trout, salmon, haddock, tuna, milk. Vit B 12 is not generally found in plant foods.

* Courtesy The Doctor’s Heart Cure – Al Sears, MD.