Vitamin B12 Deficiency
Pernicious anemia is due to lack of vitamin B12 and is characterized
by progressive nerve damage that causes forgetfulness, loss of
ability to concentrate and abnormal sensations such as burning,
itching and loss of feeling. However, many people with pernicious
anemia do not have abnormally low blood levels of vitamin B12.
A study in the Journal of the American Geriatrics Society shows that
older people have lower blood levels of a chemical called
homotranscobalamin II that carries vitamin B12 into the cells (1),
so they need higher blood levels to have normal tissue levels. Since
low-normal blood level of vitamin B12 do not rule out B12
deficiency, the diagnosis of pernicious anemia is often made late in
the course of the disease after people have suffered permanent nerve
damage. According to a report in the Archives of Internal Medicine,
two percent of Americans over 60 have low blood levels of vitamin
B12 (2), but the incidence of vitamin B12 deficiency causing nerve
damage in older people is much higher than that, sometimes as high a
50 percent (3,4). This means that many older people who are
diagnosed with senility actually suffer from lack of vitamin B12
which can be cured by taking vitamin B supplements. Many cannot
correct their B12 deficiency with diet changes, because the problem
is caused by failure to absorb B12 in the intestines (5). Lack of
vitamin B12 can cause heart attacks (6,7), so all people over 60
should be screened with blood tests for vitamin B12 and those with
normal levels of B12 and symptoms of nerve damage or
arteriosclerosis should also get a blood test called homocysteine.
Almost always, those with a deficiency can a cured by taking a 1000
microgram pill of vitamin B12 once a day. They usually do not need
to take injections. Low levels of B12 are also associated with
stomach diseases and infections such as Helicobacter pylori (see
By Gabe Mirkin, M.D., for CBS Radio News
1) J Metz, AH Bell, L Flicker, T Bottiglieri, J Ibrahim, E Seal,
D Schultz, H Savoia, KM Mcgrath. The significance of subnormal serum
vitamin B-12 concentration in older people: A case control study.
Journal of the American Geriatrics Society 44: 11 (NOV 1996):
2) Carmel R. Prevalence of undiagnosed pernicious anemia in the
elderly. Archives of Internal Medicine. 1996 (May 27); 156:
3) E Joosten, A Vandenberg, R Riezler, HJ Naurath, J Lindenbaum,
SP Stabler, RH Allen. Am J of Clin Nutr 1993 (Oct); 58(4): 468-476.
homocysteine, cystathionine, methylmalonic acid, and 2-methylcitric
4) J Lindenbaum, IH Rosenberg, PWF Wilson, SP Stabler, RH Allen.
American Journal of Clinical Nutrition 1994 (July); 60(1): 12-14.
4A) LH Allen, J Casterline. American Journal of Clinical Nutrition
1994 (July); 60(1): 2-11.
5) 6-week period of vitamin supplementation (1.0 mg folic acid,
10 mg pyridoxine, 0.05 mg cyanocobalamin. JB Ubbink, A Vandermerwe,
WJH Vermaak, R Delport. Clinical Investigator 1993 (Dec); 71(12):
6) JAMA December 8, 1993; 270 (22): 2693-98 and 2726-7.
7) homocysteine levels are associated with carotid artery stenosis.
NEJM 1995 (Feb2); 332(5): 286-291.