Download Does Food Fortification With Folate Pose a Risk of Vitamin B

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
Stillwater, OK 74078-6111
(405) 744-6824
[email protected]
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 B12 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 nonessential 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.
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Does Food Fortification With Folate Pose a Risk of Vitamin B-12 Deficiency in Senior Citizens?
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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 United States the prevalence
rate for vitamin B-12 deficiency for children,
teenagers, pregnant women and other women is
believed to be low. The long-term consequences
of vitamin B-12 deficiency are unknown, but
some speculate that vitamin B-12 deficiency
may in some respects may imitate iron
deficiency, thereby affecting the brain and
causing postnatal behavioral and learning
disabilities.
It is estimated that up to 15 percent of those
over age 60 have varying degrees of vitamin B12 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 United States. Neural tube defects occur in
human embryos and result in developmental
defects. The defects are caused by an improper
fusion of the embryo’s brain and/or spinal cord
that takes place during a series of minutely
timed sequences occurring between the 16th and
25th day of gestation. The most extreme cases of
developmental defects result in the total absence
of a brain, called anencephaly. In less severe
cases, it results in spina bifida.
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 United States government in
1998-mandated folic acid be added to all cereals
and grains (pasta, bread, and other cereal-grain
products). The amount of folate to be added was
enough to prevent neural tube defects in most
cases, but not enough so as to constitute a risk.
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 United States has
decreased from 21 percent to just one percent.
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
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Does Food Fortification With Folate Pose a Risk of Vitamin B-12 Deficiency in Senior Citizens?
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similar anemia caused by vitamin B-12
deficiency. Mandated folic acid fortification in
the diet, may however, be eliminating the most
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 B12 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 B12 deficient. Annual screening is therefore
recommended.
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