Folate and Vitamin B-12: Two Nutrients Critical for Brain Health

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Folate and Vitamin B-12: Two Nutrients Critical for Brain Health

_http://www.naturalnews.com/023134.html_

(http://www.naturalnews.com/023134.html)

 

by Barbara L. Minton _(see all articles by this author)_

(http://www.naturalnews.com/Author358.html)

 

 

(NaturalNews) Recent research documents the critical nature of two

nutrients, vitamin B-12 and folate, in brain health and the maintenance of

cognitive

functioning, including memory. Deficiencies of these key nutrients are markers

of the neuropathology leading to cognitive decline, Alzheimer's Disease, and

stroke.

 

Studies and Results

 

In the past decade, researchers have increasingly focused on an amino acid

found in the blood stream called homocysteine, as a factor playing a role in

poor memory and _brain health_ (http://www.naturalnews.com/brain_health.html) .

 

The January, 2008 edition of Neurobiology and Aging reports a study of the

changes of plasma amyloid beta protein, _homocysteine_

(http://www.naturalnews.com/homocysteine.html) , and medical temporal lobe

atrophy (MTI) in the

transition from cognitive health to mild cognitive impairment and to

_Alzheimer's

disease_ (http://www.naturalnews.com/Alzheimers_disease.html) in a cohort of

75 year-old individuals. Results indicate that whether persons with mild

cognitive impairment develop _Alzheimer's_

(http://www.naturalnews.com/Alzheimers.html) Disease may depend on an

accumulation of toxic metabolites such as

homocysteine.

 

A study in the January, 2008 edition of Prostaglandins, Leukotrienes and

Essential Fatty Acids, concluded that low blood _folate_

(http://www.naturalnews.com/folate.html) and elevated homocysteine levels are

associated with poor

brain function. They found that _folic acid_

(http://www.naturalnews.com/folic_acid.html) enhances blood levels of DHA and

_EPA_

(http://www.naturalnews.com/EPA.html) (essential omega-3 fatty acids),

nutrients which also appear to

have some beneficial effects for promoting healthy brain functioning.

 

In the November, 2007 edition of Stroke, researchers report investigating

the individual and combined effects of plasma folate, _vitamin B12_

(http://www.naturalnews.com/vitamin_B12.html) , and pyridoxal 5-phosphate

levels on the

risk of ischemic _stroke_ (http://www.naturalnews.com/stroke.html) and

transient ischemic attack in a large German cohort. (Ischemic stroke is death

to an

area of _the brain_ (http://www.naturalnews.com/the_brain.html) resulting

from an inadequate supply of blood and _oxygen_

(http://www.naturalnews.com/oxygen.html) to the brain as a result of blockage

of an artery). They concluded

that low vitamin B12 plasma levels, particularly in combination with low

folate levels, increase the risk of cerebral ischemia.

 

And as reported in the June, 2007 edition of the Journal of American College

of Nutrition, researchers investigated serum levels of folate, B12 and total

homocysteine in _elderly_ (http://www.naturalnews.com/elderly.html)

post-stroke patients, and the possible correlations with radiological markers

of

neuropathology. The data showed that folate deficiency and hyperhomocysteinemia

are prevalent in elderly post stroke patients. These two conditions are

strongly and independently associated with the development of brain atrophy.

 

Folate and Folic Acid

 

The terms folate and folic acid are used interchangeably to describe this

member of the B-vitamins. Folate is found in food as well as in metabolically

active forms in the human body. Folic acid is the form more frequently used in

supplements.

 

The role of folate in the body is to act as acceptor and donor of one-carbon

units in a variety of reactions critical to the _metabolism_

(http://www.naturalnews.com/metabolism.html) of nucleic acids and amino acids.

It plays a

vital role in _DNA_ (http://www.naturalnews.com/DNA.html) metabolism from its

precursors, thymidine and purines, and is required for the synthesis of

methionine, which is required for the synthesis of S-adenosylmethionine

(SAM-e).

SAM-e is a methyl donor used in many biological _methylation_

(http://www.naturalnews.com/methylation.html) reactions, including the

methylation of sites

within DNA and _RNA_ (http://www.naturalnews.com/RNA.html) . Methylation of

DNA is seen as playing an important role in _cancer_

(http://www.naturalnews.com/cancer.html) prevention.

 

The synthesis of the amino acid methionine requires folate as well as a

_vitamin B-12_ (http://www.naturalnews.com/vitamin_B-12.html) dependent

enzyme.

So deficiency of folate can result in decreased synthesis of methionine and

buildup of homocysteine, which may be a risk factor for heart disease as well

as neuropathology. The amount of homocysteine in the blood is regulated by

vitamin B-12, and vitamin B-6 as well as folate.

 

Folate Deficiency

 

Folate deficiency is usually caused by dietary insufficiency although it can

occur in other situations. Several medications may be contributory.

 

Folate deficiency is usually initially signaled by rising homocysteine

levels. Rapidly dividing cells are particularly vulnerable to folate deficiency

and may result in _anemia_ (http://www.naturalnews.com/anemia.html) and the

hypersegmentation of neutrophils. Progression of such anemia leads to a

decreased capacity of the blood to carry oxygen and may ultimately result in

symptoms

of fatigue, weakness, and shortness of breath. This type of anemia may also

result from vitamin B-12 deficiency.

 

Disease Prevention

 

Adequate levels of folate at time of conception have been shown to prevent

spina bifida, a devastating birth defect, and may prevent the occurrence of

other types of birth defects including certain heart defects and limb

malformation. Low levels of folate has been associated with increased incidence

of

miscarriage as well as preeclampsia on placental abruption, the separation of

the placenta from the uterus.

 

More than 80 studies have shown that even moderately elevated levels of

homocysteine in the blood increase the risk of cardiovascular diseases, while

folate-rich diets have been associated with a decreased risk of _cardiovascular

disease_ (http://www.naturalnews.com/cardiovascular_disease.html) . Of the

three vitamins that regulate homocysteine levels, folic acid has been shown to

have the greatest effect in lowering basal levels of homocysteine in the blood

when no deficiency of vitamin B-12 or vitamin B-6 is present.

 

Since cancer is thought to arise from DNA damage in excess of ongoing DNA

repair and/or the inappropriate expression of critical genes, it is possible

for folate intake to affect both DNA repair and gene expression because of the

important roles played by folate in DNA and RNA synthesis and methylation.

Consuming at least five servings of _fruits and vegetables_

(http://www.naturalnews.com/fruits_and_vegetables.html) daily has been shown

to decrease

incidence of cancer. Fruits and _vegetables_

(http://www.naturalnews.com/vegetables.html) are excellent sources of folate,

which may play a role in their

anti-carcinogenic effect. Folate from foods and folic acid supplements have

been

shown to be inversely associated with colorectal cancer risk. Studies of folate

and _breast cancer_ (http://www.naturalnews.com/breast_cancer.html) have

yielded mixed results.

 

As the noted studies indicate, folate in nucleic acid synthesis and

methylation is essential for normal brain function. Several studies have

documented

the associations between decreased folate levels and cognitive impairment in

_the elderly_ (http://www.naturalnews.com/the_elderly.html) . Individuals with

low serum folate levels were more likely to have dementia, be

institutionalized, and be depressed. Low folate levels were also associated with

increased

likelihood of short-term memory problems in the elderly.

 

Food Sources and Supplements

 

Green leafy vegetables are rich in folate as well as fruit juices, legumes,

barley, beef, bran, brewer's yeast, brown rice, cheese, chicken, dates, lamb,

lentils, salmon, tuna, liver, pork, wheat germ, whole grains, and whole

wheat.

 

The supplemental form of folate is primarily folic acid. It is available in

single ingredient and combination products such as B-complex _vitamins_

(http://www.naturalnews.com/vitamins.html) . The typical dose is 400 mcg.

 

Vitamin B-12

 

Vitamin B-12 is unique in having the largest and most complex structure of

all the vitamins, and in containing a metal ion, cobalt. Methylcobalamin and

5-deoxyadenosyl cobalamin are the forms of vitamin B-12 used in the body.

Another form, cyanocobalamin, is converted in the body.

 

Methylcobalamin, along with folate, is required for methionine synthase to

function properly as discussed above.

 

Vitamin B-12 Deficiency

 

Absorption of vitamin B-12 from food requires normal function of the

stomach, pancreas, and small intestine. The most common causes of deficiency

are the

autoimmune disorders, pernicious anemia, and malabsorption from food sources.

 

Vitamin B-12 deficiency results in impairment of the activities of B-12

requiring enzymes, and may result in impaired activity of methionine synthase.

 

The neurologic symptoms of a vitamin B-12 deficiency include tingling of the

legs or arms, numbness, difficulty walking, memory loss, disorientation, and

dementia. Tongue soreness, appetite loss, and constipation are also

associated with vitamin B-12 deficiency.

 

Disease Prevention

 

A study of 195 women later diagnosed with breast cancer and 195 age-matched

women who were not diagnosed with breast cancer concluded that among women

who were postmenopausal, the association between blood levels of vitamin B-12

and breast cancer suggested a threshold effect. The risk of breast cancer was

more than doubled in women with serum vitamin B-12 levels in the lowest

quintile compared to women in the four highest quintiles. Another study

reported

that breast cancer risk for women in the highest quartile of vitamin B-12

intake was 68% lower than those in the lowest quartile.

 

As the studies have shown, people with Alzheimer's disease often have low

blood levels of vitamin B-12. One study found lower B-12 levels in the

cerebrospinal fluid of Alzheimer's patients than in patients with other types

of

dementia.

 

Observational studies have documented as many as 30% of patients

hospitalized for depression were deficient in vitamin B-12. A cross sectional

study of

700 women over the age of 65 found that B-12 deficient women were twice as

likely to be severely depressed as non-deficient women.

 

Food Sources and Supplements

 

Only bacteria in the mouth and gut can synthesize vitamin B-12. Food sources

are animal products. Individuals over the age of 50 should obtain their B-12

from supplements because of the increased likelihood of food-bound B-12

malabsorption.

 

Over-the-counter supplements are usually made of cyanocobalamin, but

methylcobalamin is also available and is considered the better choice.

Available

forms are B-12 alone, or as part of a B vitamin complex.

 

Sources:

 

Linus Pauling Institute at Oregon State:

_http://lpi.oregonstate.edu/infocenter/vitamins/fa/_

(http://lpi.oregonstate.edu/infocenter/vitamins/fa/)

 

Linus Pauling Institute at Oregon State:

_http://lpi.oregonstate.edu/infocenter/vitamins/vitaminB12/_

(http://lpi.oregonstate.edu/infocenter/vitamins/vitaminB12/)

 

March of Dimes Pregnancy and Newborns:

_http://www.marchofdimes.com/pnhec/887.asp_

(http://www.marchofdimes.com/pnhec/887.asp)

 

 

About the author

Barbara is a school psychologist, a published author in the area of personal

finance, a breast cancer survivor using " alternative " treatments, a born

existentialist, and a student of nature and all things natural.