Homocysteine is metabolized
( chemically transformed ) into methionine and cysteine with the help of the B
vitamins; folic acid, B12, and B6 ( pyridoxine ).
Therefore, insufficient
amounts of these B vitamins in the body can theoretically hamper the metabolic
breakdown of homocysteine and hence increase its blood levels.
High levels of
homocysteine in the blood ( hyperhomocysteinemia ) can damage the inner surface
of blood vessels, promote blood clotting, and accelerate atherosclerosis.
The current state of
knowledge regarding folic acid, homocysteine, and heart attacks is as follows :
The level of blood
folate is an important determinant of the blood homocysteine level. Low blood
folate levels are associated with high blood levels of homocysteine.
Low blood folate is
common among individuals who do not take multiv itamins, but unusual among
those who do.
The consumption of
folic acid supplements or folic acid fortified cereals can increase blood
folate levels and decrease blood homocysteine levels.
In a large population
study involving women, those who had the highest consumption of folic acid (
usually in the form of multivitamins ) had fewer heart attacks than those who
consumed the least amount of folic acid.
Even though current
scientific evidence suggests that takingfolic acid and vitamin B supplements to
lower homocysteine levels should helpprevent atherosclerosis and heart attacks,
conclusive proof is still lacking because :
There are no conclusive
controlled studies demonstrating that increasing folic acid intake actually
prevents atherosclerosis and heart attacks.
There is no clinical study demonstrating that
lowering blood levels of homocysteine actually prevents atherosclerosis and
heart attacks.
There is also no
official recommendation as to who should be tested for hyperhomocysteinemia.
The optimal doses of the B vitamins, folic acid, B12, andB6, required to
prevent and treat hyperhomocysteinemia are also uncertain.
For folic acid, a daily
dose of 0.8 - 1.0 mg is probably adequate.
Abnormalities that can
not see objects at close range
Presbiopi
The eye can not see
objects at a distance and at close range.
Cataracts
Eye disease caused lens
closed by a sort membranes and can not see clearly.
Color blindness
Eye disorder which can
not distinguish colors, colors that appear only in black, gray and white.
Blindness
Eye disorder that makes
a person can not see at all.
.jpg)
0 komentar:
Posting Komentar