& Joannie Dobbs Wednesday,
Lack of B-12 widespread
IF you are suffering from a vitamin B-12 deficiency, your doctor is likely to miss it! And if you are a physician, we hope this article catches your attention.
B-12 deficiency goes undetected too frequently due to the diversity of its signs and symptoms and the complexity of its diagnosis. There also seems to be a significant lack of understanding within much of the medical community about the seriousness of this problem and its diagnosis.
Screening studies report that about one out of seven people 65 years and older are deficient in B-12. An Australian study published last year reported that 73 percent of 245 Seventh-day Adventist ministers who were consuming a vegetarian diet had serum B-12 levels below recommended levels. With this high incidence, it is surprising that there isn't a national screening program for B-12 status in the older population.
Every doctor knows that the classical sign of B-12 deficiency described in medical textbooks is an anemia characterized by enlarged red blood cells (called megaloblastic anemia). However, we now know that this is often not the first sign of a deficiency.
In this year's Annual Review of Medicine, Dr. Ralph Carmel from New York Methodist Hospital expresses his frustration with this common misconception. He states, "The proscription that cobalamin [B-12] deficiency should not be diagnosed unless megaloblastic changes are found is akin to requiring jaundice (yellow skin) to diagnose liver disease." Serious damage to the nervous system can occur due to B-12 deficiency with no detectable change in red blood cells.
A common first symptom of B-12 deficiency is an abnormal sensation in the feet such as numbness, burning, prickling or crawling sensations.
Some experience numbness in their fingers, hands, and forearms, while some people who develop this deficiency never have these symptoms.
Sometimes the first symptoms take the form of memory problems, mild to serious depression, paranoia and dementia. It is likely that many people diagnosed with Alzheimer's disease actually suffer from B-12 deficiency.
Loss of vision sharpness is yet another possible first symptom. This most commonly affects the center of the field of vision which is a symptom similar to that of age related macular degeneration.
Why are the effects of this deficiency so variable? A vitamin B-12 deficiency can affect virtually any part of the nervous system. It can affect the spinal cord, brain, optic nerves that serve the eyes and the "peripheral" nerves that serve the extremities such as hands, feet, arms and legs. Consequently, the sensations and pains that occur depend on which nerves are affected first.
The effects of this nerve damage are irreversible unless treated promptly. However, B-12 deficiency has multiple causes and therefore it is essential to determine the cause of the problem in order to choose the correct treatment. The three main causes are: 1) decreased stomach acid making B-12 unavailable for absorption, 2) decreased consumption of B-12 as in strict vegetarian diets and 3) loss of the ability to synthesize a chemical called the intrinsic factor. This factor is needed for the absorption of B12 from the diet or supplement
See our next column (Sept. 27) to learn ways to diagnose the deficiency, treatment options and why a B-12 supplement may not be the solution.
Alan Titchenal, Ph.D., C.N.S. and Joannie Dobbs, Ph.D., C.N.S.
are nutritionists in the Department of Human Nutrition, Food and Animal Sciences,
College of Tropical Agriculture and Human Resources, UH-Manoa.
Dr. Dobbs also works with the University Health Service
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