F&N
2-6
9/2003
Research Update
Does Food Fortification With Folate Pose
a Risk of Vitamin B-12 Deficiency in Senior Citizens?
Prepared by: Janice Hermann, Ph.D., R.D./L.D.
Nutrition Education
Specialist
104 HES, NSCI, Room 321
Cooperative Extension
Service
(405) 744-6824
Food Industry Environmental Network (FIEN). Accessed July
2003.
IMPLICATIONS
FOR COOPERATIVE EXTENSION. Growing older
carries more risks, among them the risk for vitamin B-12 deficiency. For most
people, B-12 deficiency is more commonly associated with anemia than with its
more subtle but potentially grave complications. Folic acid can mask vitamin
B-12 deficiency symptoms. Since
the American diet has been fortified with folic acid, in an effort to reduce
the risk of neural tube defects, it is important that the elderly and those who
care for them should ensure they have not become vitamin B-12 deficient. The
following is a review of the role of vitamin B-12 and folic acid.
Background
Normal metabolism of homocysteine
requires at least three, and probably four, vitamins including vitamin B-12,
folic acid (folate), vitamin B-6, and riboflavin. Deficiencies of vitamin B-12,
as with deficiencies of folic acid can cause high levels of homocysteine. The
metabolism of vitamin B-12 and folic acid is closely intertwined and deficiency
of either one can produce anemia. Deficiencies of both are commonly found among
the elderly. While these vitamins are alike, and work together to carry out many
of the body’s critical functions, they also differ.
Vitamin
B-12
Vitamin B-12 is the largest known vitamin.
It is a complex molecule, stored in the liver, kidneys, and tissues of the
body. Vitamin B-12 is consumed through food sources such as meat, liver, fish,
yogurt, and many dairy products and can also be taken through oral supplement
and injections. Vitamin B-12 helps to build red blood cells and maintain the
nervous system. Conversely, vitamin B-12 deficiency is often present in persons
with high levels of homocysteine. While homocysteine, a non-essential amino
acid, is normally present in low concentrations in the blood, individuals with
high levels have a significantly greater risk for cardiovascular disease,
although the direct link has not yet been established.
Vitamin B-12 deficiency can also result
in anemia (lower levels of red blood cells) and damage to the nervous system.
Common symptoms for the deficiency are fatigue from anemia, mental confusion
and sensory and movement difficulties.
Vegans (strict vegetarians who do not eat
meat, fish or eggs), and those taking medications which block stomach acid
production and thus B-12 absorption, are at highest risk for the deficiency. In
the
It is estimated that up to 15 percent of
those over age 60 have varying degrees of vitamin B-12 deficiency. Moreover,
three percent of those over 65 are estimated to develop pernicious anemia, a
reduction in the number of red blood cells due to malabsorption of vitamin B-12
caused by a failure of the gastric mucosa to secrete a substance called the intrinsic
factor, which is necessary for normal vitamin B-12 absorption. H-pylori, a
bacteria responsible for a variety of stomach ailments, including gastric and
duodenal ulceration and atrophy of the stomach lining, occurs quite commonly in
some populations. When H-pylori infection is present the normal absorption of
vitamin B-12 is hindered.
Folic
Acid
Not long ago, the most common, modifiable
cause of high levels of homocysteine was folic acid deficiency.
Before 1998, between 4,000 and 5,000
children were born with neural tube defects annually in the
In the mid-1990’s, studies of women in
Ireland, Hungary and other European countries determined that women who had
previously had neural tube defect pregnancies but later received supplemental
amounts of folic acid lowered their risk of neural tube defects in subsequent
pregnancies.
Since no educational campaign was likely
to reach women within the first 25 days of pregnancy to urge them to take
supplemental folic acid, the
Since the American diet has been fortified
with folic acid, there has been a 20 percent overall reduction in neural tube
defects. In addition, folic acid deficiency in the
Good
News, Bad News
Folic acid deficiency also causes a certain
type of anemia and large amounts of folic acid can reverse or prevent this
anemia, as well as a similar anemia caused by vitamin B-12 deficiency. Mandated folic acid fortification in the
diet, may however, be eliminating the most obvious manifestation of vitamin
B-12 deficiency in the elderly - anemia. Because vitamin B-12 and folic acid
are so similar, consumption of folic acid may be preventing fatigue, a classical
sign of anemia and vitamin B-12 deficiency. The concern among physicians is
that without symptoms of fatigue many elderly people will forego visiting their
physician, who would diagnose vitamin B-12 deficiency, if present. The longer
vitamin B-12 deficiency goes undetected, the longer the brain and nervous
systems undergo progressive deterioration due to the vitamin B-12 deficiency.
This can culminate in a greater risk for dementia as well as paralysis that can
result from vitamin B-12 deficiency. Prevention of vitamin B-12 deficiency is
therefore important not just for the potential consequences to the heart, but
to prevent dementia in the elderly.
Treatment
The key to preventing vitamin B-12
deficiency is a balanced diet, particularly among the elderly. But some individuals, despite following a
nutritious diet plan, may not be able to absorb vitamin B-12. Therefore, to
rule out vitamin B-12 deficiency, screening is recommended. If vitamin B-12
deficiency is diagnosed, individuals may be prescribed a large oral vitamin
B-12 supplement or vitamin B-12 injections.
Conclusions
Because we are eating more folic acid in
our diet, the elderly and those who care for them should ensure they have not
become vitamin B-12 deficient. Annual screening is therefore recommended.