Re: Folate
- From: rpautrey2 <rpautrey2@xxxxxxxxx>
- Date: Thu, 20 Dec 2007 19:34:22 -0800 (PST)
Folate
What can high-folate foods do for you?
Support red blood cell production and help prevent anemia
Help prevent homocysteine build-up in your blood
Support cell production, especially in your skin
Allow nerves to function properly
Help prevent osteoporosis-related bone fractures
Help prevent dementias including Alzheimer's disease
What events can indicate a need for more high-folate foods?
Irritability
Mental fatigue, forgetfulness, or confusion
Depression
Insomnia
General or muscular fatigue
Gingivitis or periodontal disease
Excellent sources of folate include romaine lettuce, spinach,
asparagus, turnip greens, mustard greens, calf's liver, parsley,
collard greens, broccoli, cauliflower, beets, and lentils.
For serving size for specific foods, see Nutrient Rating Chart below
at the bottom of this page.
Description
Function
Deficiency Symptoms
Toxicity Symptoms
Cooking, storage and processing
Factors that affect function
Drug-nutrient interaction
Nutrient interaction
Health conditions
Supplements
Food Sources
Public Recommendations
References
Description
What is folate?
Folic acid, also called folate or folacin, is a B-complex vitamin most
publicized for its importance in pregnancy and prevention of pregnancy
defects. These defects involve malformation of a structure in the
fetus called the neural tube. As the baby develops, the top part of
this tube helps form the baby's brain, and the bottom part unfolds to
become the baby's spinal column.
When the neural tube fails to close properly, serious brain and spinal
problems result. Mothers with inadequate supplies of folic acid have
been determined to give birth to a greater number of infants with
neural tube defects. Beginning in the early 1980's, researchers began
to successfully use folic acid supplementation to reduce the risk of
nervous system problems in newborn infants.
Folic acid is one of the most chemically complicated vitamins, with a
three-part structure that puts special demands on the body's
metabolism. The three primary components of folic acid are called
PABA, glutamic acid, and pteridine. (Two of these components, glutamic
acid and pteridine, help explain the technical chemical name for
folate, namely pteroylmonoglutamate.)
As complex as this vitamin is in its structure, it is equally as
complicated in its interaction with the human body. For example, most
foods do not contain folic acid in the exact form described above, and
enzymes inside the intestine have to chemically alter food forms of
folate in order for this vitamin to be absorbed. Even when the body is
operating at full efficiency, only about 50% of ingested food folate
can be absorbed.
How it Functions
What is the function of folate?
Red blood cell formation and circulation support
One of folate's key functions as a vitamin is to allow for complete
development of red blood cells. These cells help carry oxygen around
the body. When folic acid is deficient, the red bloods cannot form
properly, and continue to grow without dividing. This condition is
called macrocytic anemia, and one of its most common causes is folic
acid deficiency.
In addition to its support of red blood cell formation, folate also
helps maintain healthy circulation of the blood throughout the body by
preventing build-up of a substance called homocysteine. A high serum
homocysteine level (called hyperhomocysteinemia) is associated with
increased risk of cardiovascular disease, and low intake of folate is
a key risk factor for hyperhomocysteinemia. Increased intake of folic
acid, particularly by men, has repeatedly been suggested as a simply
way to lower risk of cardiovascular disease by preventing build-up of
homocysteine in the blood.
Preliminary research also suggests that high homocysteine levels can
lead to the deterioration of dopamine-producing brain cells and may
therefore contribute to the development of Parkinson's disease.
Therefore, folate deficiency may have an important relationship to
neurological health.
Research is now confirming a link between blood levels of folate and
not only cardiovascular disease, but dementias, including Alzheimer's
disease.
One of the most recent studies, which was published in the July 2004
issue of the American Journal of Clinical Nutrition evaluated 228
subjects. In those whose blood levels of folate were lowest, the risk
for mild cognitive impairment was more than tripled, and risk of
dementia increased almost four fold. Homocysteine, a potentially
harmful product of cellular metabolism that is converted into other
useful compounds by folate, along with vitamin B6 and B 12, was also
linked to dementia and Alzheimer's disease. Individuals whose
homocysteine levels were elevated had a 4.3 (more than four fold)
increased risk of dementia and a 3.7 (almost four fold) increased risk
of Alzheimer's disease.
Research teams in the Netherlands and the U.S. have confirmed that low
levels of folic acid in the diet significantly increases risk of
osteporosis-related bone fractures due to the resulting increase in
homocysteine levels. Homocysteine has already been linked to damage to
the arteries and atherosclerosis, plus increased risk of dementia in
the elderly. Now, in a study that appeared in the May 2004 issue of
the New England Journal of Medicine, researchers at the Eramus Medical
Center, Rotterdam, Holland, and another team in Boston have confirmed
that individuals with the highest levels of homocysteine have a much
higher risk of osteoporotic fracture.
In the Rotterdam study, which included 2,406 subjects aged 55 years or
older, those with the highest homocysteine levels, whether men or
women, almost doubled their risk of fracture. The Boston team found
that risk of hip fracture nearly quadrupled in men and doubled in
women in the top 25% of homocysteine levels.
Both groups found that folic acid reduced the risk of osteoporotic
fractures by reducing high levels of homocysteine. While the
researchers are suggesting that bread and cereal products intended for
the elderly should be fortified with folic acid to reduce homocysteine
levels and thus the risk of bone fracture, we at the World's
Healthiest Foods have a simpler suggestion: Eat a minimum of 5
servings of folic acid-rich foods each day! Why settle just for folic
acid when these vegetables provide not only folic acid, but hundreds
of other nutrients that promote your health and well-being in dozens
of ways. Plus, with the quick, easy and delicious recipes George
Mateljan has created for you, getting your folic acid can be an
infinitely more interesting and pleasant experience than eating a
piece of fortified bread!
Cell Production
Cells with very short life spans (like skin cells, intestinal cells,
and most cells that line the body's exposed surfaces or cavities) are
highly dependent on folic acid for their creation. For this reason,
folic acid deficiency has repeatedly been linked to problems in these
types of tissue.
In the mouth, these problems include gingivitis, cleft palate, and
periodontal disease. In the skin, the most common folate deficiency-
related condition is seborrheic dermatitis. Vitiligo (loss of skin
pigment) can also be related to folic acid deficiency. Cancers of the
esophagus and lung, uterus and cervix, and intestine (especially the
colon) have been repeatedly linked to folate deficiency.
Nervous system support
Prevention of neural tube defects in newborn infants is only one of
the nervous system-related functions of folic acid. Deficiency of
folate has been linked to a wide variety of nervous system problems,
including general mental fatigue, non-senile dementia, depression,
restless leg syndrome, nervous system problems in the hands and feet,
irritability, forgetfulness, confusion, and insomnia. The link between
folate and many of these conditions may involve the role of folate in
maintaining proper balance in nervous system's message-carrying
molecules. These molecules, called neurotransmitters, often depend
upon folic acid for their synthesis.
Deficiency Symptoms
What are deficiency symptoms for folate?
Because of its link with the nervous system, folate deficiency can be
associated with irritability, mental fatigue, forgetfulness,
confusion, depression, and insomnia. The connections between folate,
circulation, and red blood cell status make folate deficiency a
possible cause of general or muscular fatigue. The role of folate in
protecting the lining of body cavities means that folate deficiency
can also result in intestinal tract symptoms (like diarrhea) or mouth-
related symptoms like gingivitis or periodontal disease.
Toxicity Symptoms
What are toxicity symptoms for folate?
At very high doses greater than 1,000-2,000 micrograms, folate intake
can trigger the same kinds of nervous system-related symptoms that it
is ordinarily used to prevent. These symptoms include insomnia,
malaise, irritability, and intestinal dysfunction. Primarily for these
reasons, the Institute of Medicine at the National Academy of Sciences
set a tolerable upper limit (UL) in 1998 of 1,000 mcg for men and
women 19 years and older. This UL was only designed to apply to
"synthetic folate" defined as the forms obtained from supplements and/
or fortified foods.
Impact of Cooking, Storage and Processing
How do cooking, storage, or processing affect folate?
Folate contained in animal products (like beef liver) appears to be
relatively stable to cooking, unlike folate in plant products (like
cabbage) which can lose up to 40% of their folate content from
cooking. Processed grains and flours can lose up to 70% of their
folate, and despite this processing loss, processed grains and flours
are not required to be enriched with folate, even though they are
legally required to be enriched with other B vitamins including B1,
B2, and B3.
Factors that Affect Function
What factors might contribute to a deficiency of folate?
In addition to poor dietary intake of folate itself, deficient intake
of other B vitamins can contribute to folate deficiency. These
vitamins include B1, B2, and B3 which are all involved in folate
recycling. Poor protein intake can cause deficiency of folate binding
protein which is needed for optimal absorption of folate from the
intestine, and can also be related to an insufficient supply of
glycine and serine, the amino acids that directly participate in
metabolic recycling of folate. Excessive intake of alcohol, smoking,
and heavy coffee drinking can also contribute to folate deficiency.
Drug-Nutrient Interactions
What medications affect folate?
Medications that can help deplete the body's supply of folate include:
anticancer drugs like methotrexate; cholesterol-lowering drugs like
cholestyramine; anti-inflammatory drugs like sulfasalazine; biguanide
drugs like buformin, phenformin, or metformin used in the treatment of
diabetes; birth control pills (oral contraceptives); potassium-sparing
diuretics like triamterene; and antibiotics like trimethoprim or
pyrimethamine. While the anti-convulsant drug phenytoin (sold under
the brand name of Dilantin or Phenytek) remains somewhat controversial
in terms of its impact on folate, several animal studies have shown a
lowering of the liver's ability to make polyglutamyl forms of this
vitamin following adminstration of phenytoin.
Nutrient Interactions
How do other nutrients interact with folate?
Vitamins B1, B2, and B3 must be present in adequate amounts to enable
folic acid to undergo metabolic recycling in the body. Excessive
amounts of folic acid, however, can hide a vitamin B12 deficiency, by
masking blood-related symptoms.
Health Conditions
What health conditions require special emphasis on folate?
Folate may play a role in the prevention and/or treatment of the
following health conditions:
Alcoholism
Anemias (especially macrocytic anemia)
Atherosclerosis
Cervical dysplasia
Cervical tumors
Cleft palate or cleft lip
Crohn's disease
Depression
Diarrhea
Gingivitis
Glossitis
Glycogen storage disease type I
Hyperhomocysteinemia
Inflammatory bowel disease
Insomnia
Myelopathy
Neural tube defects
Non-senile dementia
Ovarian tumors
Periodontal disease
Restless leg syndrome
Schizophrenia
Seborrheic dermatitis
Tropical sprue
Uterine tumors
Form in Dietary Supplements
What forms of folate are found in dietary supplements?
Folic acid is normally found in its simple form (also called
pteroylmonoglutamic acid) in dietary supplements. Folinic acid (also
called 5-formyltetrahydrofolate) is also available, and can help by-
pass certain biochemical steps that occur in the body once folate has
been absorbed from the intestine.
Food Sources
What foods provide folate?
Excellent sources of folate include romaine lettuce, spinach,
asparagus, turnip greens, mustard greens, calf's liver, parsley,
collard greens, broccoli, cauliflower, beets, and lentils.
Very good sources include squash, black beans, pinto beans, garbanzo
beans, papaya and string beans.
Introduction to Nutrient Rating System Chart
In order to better help you identify foods that feature a high
concentration of nutrients for the calories they contain, we created a
Food Rating System. This system allows us to highlight the foods that
are especially rich in particular nutrients. The following chart shows
the World's Healthiest Foods that are either an excellent, very good,
or good source of folate. Next to each food name, you'll find the
serving size we used to calculate the food's nutrient composition, the
calories contained in the serving, the amount of folate contained in
one serving size of the food, the percent Daily Value (DV%) that this
amount represents, the nutrient density that we calculated for this
food and nutrient, and the rating we established in our rating system.
For most of our nutrient ratings, we adopted the government standards
for food labeling that are found in the U.S. Food and Drug
Administration's "Reference Values for Nutrition Labeling." Read more
background information and details of our rating system.
World's Healthiest Foods ranked as quality sources of:
folate
Food Serving
Size Cals Amount
(mcg) DV
(%) Nutrient
Density World's
Healthiest
Foods Rating
Romaine lettuce 2 cup 15.7 151.98 38.0 43.6 excellent
Spinach, boiled 1 cup 41.4 262.44 65.6 28.5 excellent
Asparagus, boiled 1 cup 43.2 262.80 65.7 27.4 excellent
Turnip greens, cooked 1 cup 28.8 170.50 42.6 26.6 excellent
Mustard greens, boiled 1 cup 21.0 102.76 25.7 22.0 excellent
Calf's liver, braised 4 oz-wt 187.1 860.70 215.2 20.7 excellent
Parsley, fresh 2 tbs 2.7 11.40 2.9 19.0 good
Kelp (sea vegetable) 0.25 cup 8.6 36.00 9.0 18.8 very good
Collard greens, boiled 1 cup 49.4 176.70 44.2 16.1 excellent
Broccoli, steamed 1 cup 43.7 93.91 23.5 9.7 excellent
Cauliflower, boiled 1 cup 28.5 54.56 13.6 8.6 excellent
Beets, Boiled 1 cup 74.8 136.00 34.0 8.2 excellent
Celery, raw 1 cup 19.2 33.60 8.4 7.9 very good
Lentils, cooked 1 cup 229.7 357.98 89.5 7.0 excellent
Brussel sprouts, boiled 1 cup 60.8 93.60 23.4 6.9 very good
Pinto beans, cooked 1 cup 234.3 294.12 73.5 5.6 very good
Black beans, cooked 1 cup 227.0 255.94 64.0 5.1 very good
Garbonzo beans (chickpeas), cooked 1 cup 269.0 282.08 70.5 4.7 very
good
Kidney beans, cooked 1 cup 224.8 229.39 57.3 4.6 very good
Summer squash, cooked, slices 1 cup 36.0 36.18 9.0 4.5 very good
Cucumbers, slices, with peel 1 cup 13.5 13.52 3.4 4.5 good
Navy beans, cooked 1 cup 258.4 254.62 63.7 4.4 very good
Papaya 1 each 118.6 115.52 28.9 4.4 very good
Green beans, boiled 1 cup 43.8 41.63 10.4 4.3 very good
Cabbage, shredded, boiled 1 cup 33.0 30.00 7.5 4.1 very good
Fennel, raw, sliced 1 cup 27.0 23.50 5.9 3.9 very good
Bell peppers, red, raw, slices 1 cup 24.8 20.24 5.1 3.7 very good
Leeks, boiled 0.50 cup 16.1 12.64 3.2 3.5 good
Green peas, boiled 1 cup 134.4 101.28 25.3 3.4 very good
Lima beans, cooked 1 cup 216.2 156.23 39.1 3.3 good
Winter squash, baked, cubes 1 cup 80.0 57.40 14.3 3.2 good
Tomato, ripe 1 cup 37.8 27.00 6.8 3.2 good
Oranges 1 each 61.6 39.69 9.9 2.9 good
Crimini mushrooms, raw 5 oz-wt 31.2 19.85 5.0 2.9 good
Strawberries 1 cup 43.2 25.49 6.4 2.7 good
Flaxseeds 2 tbs 95.3 53.86 13.5 2.5 good
Split peas, cooked 1 cup 231.3 127.20 31.8 2.5 good
Raspberries 1 cup 60.3 31.98 8.0 2.4 good
Eggplant, cooked, cubes 1 cup 27.7 14.26 3.6 2.3 good
Onions, raw 1 cup 60.8 30.40 7.6 2.3 good
Cantaloupe, cubes 1 cup 56.0 27.20 6.8 2.2 good
Kale, boiled 1 cup 36.4 17.29 4.3 2.1 good
Swiss chard, boiled 1 cup 35.0 15.05 3.8 1.9 good
Corn, yellow, cooked 1 cup 177.1 76.10 19.0 1.9 good
Peanuts, raw 0.25 cup 207.0 87.53 21.9 1.9 good
Grapefruit 0.50 each 36.9 15.01 3.8 1.8 good
Sunflower seeds, raw 0.25 cup 205.2 81.86 20.5 1.8 good
Avocado, slices 1 cup 235.1 90.37 22.6 1.7 good
Carrots, raw 1 cup 52.5 17.08 4.3 1.5 good
World's Healthiest
Foods Rating Rule
excellent DV>=75% OR Density>=7.6 AND DV>=10%
very good DV>=50% OR Density>=3.4 AND DV>=5%
good DV>=25% OR Density>=1.5 AND DV>=2.5%
Public Health Recommendations
What are current public health recommendations for folate?
The Recommended Dietary Allowances for folic acid, set in 1998 by the
Institute of Medicine at the National Academy of Sciences, are as
follows:
0-6 months: 65 micrograms
6-12 months: 80 micrograms
1-3 years: 150 micrograms
4-8 years: 200 micrograms
Males 9-13 years: 300 micrograms
Males 14 years and older: 400 micrograms
Females 9-13 years: 300 micrograms
Females 14 years and older: 400 micrograms
Pregnant females of any age: 600 micrograms
Lactating females of any age: 500 micrograms
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© 2001-2007 The George Mateljan Foundation
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