Medical researchers and medical journals have been warning for decades that anyone (regardless of diet) can become B-12 deficient. Occasionally it happens early in life, but it becomes more common by middle age.

If B-12 deficiency is not eliminated while the damage is minor, it is common for the spinal cord to become damaged, or the patient may be misdiagnosed with Alzheimer's and die of heart failure. This may happen within a few years, or over decades, depending on the extent of malabsorption. And because symptoms are often so subtle for a long time, the problems may seem sudden, even though they have been worsening for a quite a while.

Research throughout recent decades has shown that people who have neurologic damage as a result of B-12 malabsorption are misdiagnosed much more often than thought previously. They are being allowed to worsen unnecessarily for lack of a safe and inexpensive vitamin.

People who have neurological symptoms should be tested and/or treated immediately (not after weeks, months or years of other testing or waiting). If testing is not possible, they should take at least 1000 mcg B-12 while continuing to look at other possibilities. If B-12 deficiency is the cause, they will almost surely stop the damage within weeks and then their bodies will have an opportunity to begin a months-long (years in more serious cases) process of repair. The earlier deficiency is treated, the more likely is complete repair.