The VITACOG trial
a preliminary clinical trial in subjects with high plasma homocysteine
levels, showed that the brains of those who received B-vitamins shrank significantly less rapidly
than those of the placebo group, particularly in areas that are associated with early pathological changes in Alzheimer’s.
Author believes there were flaws in the analysis.
What happens if I don’t get enough vitamin B12? (from NIH fact page)
Vitamin B12 deficiency causes tiredness, weakness, constipation, loss
of appetite, weight loss, and megaloblastic anemia. Nerve problems,
such as numbness and tingling in the hands and feet, can also occur.
Other symptoms of vitamin B12 deficiency include problems with balance,
depression, confusion, dementia
poor memory, and soreness of the mouth or tongue. Vitamin B12
deficiency can damage the nervous system even in people who don’t have
anemia, so it is important to treat a deficiency as soon as possible.
In infants, signs of a vitamin B12 deficiency include failure to thrive
, problems with movement, delays in reaching the typical developmental milestones, and megaloblastic anemia.
Large amounts of folic acid can hide a vitamin B12 deficiency by
correcting megaloblastic anemia, a hallmark of vitamin B12 deficiency.
But folic acid does not correct the progressive damage to the nervous
system that vitamin B12 deficiency also causes. For this reason, healthy
adults should not get more than 1,000 mcg of folic acid a day.
What are some effects of vitamin B12 on health?
Scientists are studying vitamin B12 to understand how it affects
health. Here are several examples of what this research has shown:
Vitamin B12 supplements (along with folic acid and vitamin B6) do not
reduce the risk of getting heart disease. Scientists had thought that
these vitamins might be helpful because they reduce blood levels of homocysteine
, a compound linked to an increased risk of having a heart attack or stroke.
As they get older, some people develop dementia. These people often
have high levels of homocysteine in the blood. Vitamin B12 (with folic
acid and vitamin B6) can lower homocysteine levels, but scientists don’t
know yet whether these vitamins actually help prevent or treat
Energy and athletic performance
Advertisements often promote vitamin B12 supplements as a way to
increase energy or endurance. Except in people with a vitamin B12
deficiency, no evidence shows that vitamin B12 supplements increase
energy or improve athletic performance.
What are some effects of vitamin B6 on health? (from NIH fact page)
Scientists are studying vitamin B6 to understand how it affects health. Here are some examples of what this research has shown.
Some scientists had thought that certain B vitamins (such as folic
acid, vitamin B12, and vitamin B6) might reduce heart disease risk by
lowering levels of homocysteine, an amino acid in the blood. Although
vitamin B supplements do lower blood homocysteine, research shows that
they do not actually reduce the risk or severity of heart disease or
People with low levels of vitamin B6 in the blood might have a higher
risk of certain kinds of cancer, such as colorectal cancer. But studies
to date have not shown that vitamin B6 supplements can help prevent
cancer or lower the chances of dying from this disease.
Some research indicates that elderly people who have higher blood
levels of vitamin B6 have better memory. However, taking vitamin B6
supplements (alone or combined with vitamin B12 and/or folic acid) does
not seem to improve cognitive function or mood in healthy people or in
people with dementia.
Scientists aren’t yet certain about the potential benefits of taking
vitamin B6 for premenstrual syndrome (PMS). But some studies show that
vitamin B6 supplements could reduce PMS symptoms, including moodiness,
irritability, forgetfulness, bloating, and anxiety.
Nausea and Vomiting in Pregnancy
At least half of all women experience nausea, vomiting, or both in
the first few months of pregnancy. Based on the results of several
studies, the American Congress of Obstetricians and Gynecologists (ACOG)
recommends taking vitamin B6 supplements under a doctor’s care for
nausea and vomiting during pregnancy.
Can vitamin B6 be harmful?
Not from food, but taking high levels of vitamin B6 from supplements for a year or longer can cause severe nerve damage which goes away when you discontinue.
What are some effects of folate on health? (from NIH fact page)
Scientists are studying folate to understand how it affects health. Here are several examples of what this research has shown.
Neural tube defects
Taking folic acid regularly before becoming pregnant and during early pregnancy helps prevent
neural tube defects in babies. But about half of all pregnancies are
unplanned. Therefore, all women and teen girls who could become pregnant
should consume 400 mcg of folic acid daily from supplements, fortified
foods, or both in addition to the folate they get naturally from foods.
Since 1998, the U.S. Food and Drug Administration
has required food companies to add folic acid to enriched bread,
cereal, flour, cornmeal, pasta, rice, and other grain products sold in
the United States. Because most people in the United States eat these
foods on a regular basis, folic acid intakes have increased and the
number of babies born with neural tube defects has decreased since 1998.
Preterm birth, congenital heart defects, and other birth defects
Taking folic acid might reduce the risk of having a premature baby
and prevent birth defects, such as congenital heart problems. But more
research is needed to understand how folic acid affects the risk of
Folate that is found naturally in food may decrease the risk of several forms of cancer
But folate might have different effects depending on how much is taken
and when. Modest amounts of folic acid taken before cancer develops
might decrease cancer risk, but high doses
taken after cancer (especially colorectal cancer) begins might speed up
its progression. For this reason, high doses of folic acid supplements
(more than the upper limit of 1,000 mcg) should be taken with caution,
especially by people who have a history of colorectal adenomas (which
sometimes turn into cancer). More research is needed to understand the
roles of dietary folate and folic acid supplements in cancer risk.
Heart disease and stroke
Some scientists used to think that folic acid and other B-vitamins might reduce heart disease
risk by lowering levels of homocysteine
, an amino acid
in the blood. But although folic acid supplements do lower blood
homocysteine levels, they don’t decrease the risk of heart disease. Some
studies have shown that a combination of folic acid with other
B-vitamins, however, helps prevent stroke
Dementia, cognitive function, and Alzheimer’s disease
Folic acid supplements with or without other B-vitamins do not seem to improve cognitive function
, but more research on this topic is needed.
People with low blood levels of folate might be more likely to suffer from depression
and might not respond as well to treatment with antidepressants as people with normal folate levels.
Folic acid supplements might make antidepressant medications more
effective. But it is not clear whether these supplements help people
with both normal folate levels and those with folate deficiency. More
research is needed to learn about the role of folate in depression and
whether folic acid supplements are helpful when used in combination with
Can folate be harmful?
Folate that is naturally present in food is not harmful. Folic acid
in supplements and fortified foods, however, should not be consumed in
amounts above the upper limit, unless recommended by a health care provider
Labels: Alzheimer's Disease, homocysteine, vitamin B