Re: Vitamin B6
- From: rpautrey2 <rpautrey2@xxxxxxxxx>
- Date: Mon, 24 Dec 2007 13:06:30 -0800 (PST)
vitamin B6
What can foods high in vitamin B6 do for you?
Support a wide range of activities in your nervous system
Promote proper breakdown of sugars and starches
Help prevent homocysteine build-up in your blood
What events can indicate a need for more high-vitamin B6 foods ?
Fatigue or malaise
Anemia
Skin disorders including eczema and seborrheic dermatitis
Convulsions or seizures
Excellent sources of vitamin B6 include bell peppers, turnip greens,
and spinach.
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 vitamin B6?
First researched in the mid-1930's, vitamin B6 is one of the best-
studied of all B vitamins and has one of the greatest varieties of
chemical forms. The forms of this vitamin all begin with the letters
"pyr," and include pyridoxine, pyridoxal, pyridoxamine, pyridoxine
phosphate, pyridoxal phosphate, and pyridoxamine phosphate.
The vitamin was not originally given this name, however, but was
referred to as "antidermatitis factor." This term pointed to the skin
(dermis) because skin inflammation (dermatitis) seemed to increase
when foods with B6 were eliminated from the diet. Topical B6 creams
are used to this day in treatment of skin inflammation, particularly
in relationship to symptoms of seborrheic dermatitis.
How it Functions
What is the function of vitamin B6?
Much of the body's chemistry depends upon enzymes. Enzymes are
proteins that help chemical reactions take place. Because vitamin B6
is involved with more than 100 enzymatic reactions, its function in
the body is diverse and far-reaching.
Synthesis of essential molecules
It is difficult to find a chemical category of molecules in the body
that do not depend in some way on vitamin B6 for their production.
Many of the building blocks of protein, called amino acids, require
adequate supplies of B6 for synthesis. Nucleic acids used in the
creation of DNA in our genes also require this vitamin.
Because amino acids and nucleic acids are such critical parts of new
cell formation, vitamin B6 can be regarded as an essential part of the
formation of virtually all new cells in the body. Heme (the protein
center of our red blood cells) and phospholipids (our cell membrane
components that allow messaging between cells) also depend on vitamin
B6 for their creation.
Processing of carbohydrate
The processing of carbohydrate (sugar and starch) in our body depends
on availability of vitamin B6. This vitamin is particularly important
in facilitating the breakdown of glycogen (a special form of starch)
stored in our muscle cells and to a lesser extent in our liver.
Because carbohydrate processing plays such a key role in certain types
of athletic events, researchers have looked closely at the role
vitamin B6 plays in carbohydrate processing during physical
performance.
Support of nervous system activity
The role of vitamin B6 in our nervous system is very broad, and
involves many aspects of neurological activity. One aspect focuses on
the creation of an important group of messaging molecules called
amines. The nervous system relies on formation of these molecules for
transmission of messages from one nerve to the next. (The molecules
can be classified as "neurotransmitters" for this reason.) Amines are
one type of neurotransmitter in the nervous system. They are often
made from parts of protein called amino acids, and the key nutrient
for making this process happen is vitamin B6. Some of the amine-
derived neurotransmitters that require vitamin B6 for their production
include serotonin, melatonin, epinephrine, norepinephrine, and GABA.
Support of sulfur and methyl metabolism
The movement of sulfur-containing molecules around the body is
especially important for hormonal balance and elimination of toxic
substances through the liver. Because vitamin B6 is able to remove
sulfur groups from other molecules, it helps the body maintain
flexibility in handling sufur-containing compounds.
Vitamin B6 plays a similar role with respect to methyl-containing
molecules. The term "methyl group" refers to a chemical structure that
has only one carbon atom and three hydrogen atoms. Many important
chemical events in the body are made possible by the transfer of
methyl groups from one place to another. For example, genes in the
body can be switched on and turned off in this way, and cells can use
the process to send messages back and forth.
The attachment of methyl groups to toxic substances is one way of
making them less toxic and encouraging their elimination from the
body. It is also a way of ensuring that substances like homocysteine,
which can build up excessively in the blood and lead to risk of
cardiovascular disease, are kept within a healthy range.
Deficiency Symptoms
What are deficiency symptoms for vitamin B6?
Because of its key role in the formation of new cells, vitamin B6 is
especially important for healthy function of body tissue that
regenerates itself quickly. The skin is exactly this type of tissue,
and it is one of the first to show problems when B6 is deficient. Many
skin disorders have been associated with B6 deficiency, and they
include eczema and seborrheic dermatitis.
The key role of vitamin B6 in the nervous system also results in many
nerve-related symptoms when B6 is deficient. These symptoms can
include convulsions and seizures in the case of severe deficiency. The
critical role of vitamin B6 in the formation of red blood cells means
that B6 deficiency can also result in symptoms of anemia, malaise, and
fatigue. When anemia is exclusively related to B6 deficiency, it is
usually classified as hypochromic, microcytic (pernicious) anemia.
Toxicity Symptoms
What are toxicity symptoms for vitamin B6?
Imbalances in nervous system activity have been shown to result from
high levels of supplemental vitamin B6 intake. These imbalances do not
seem to occur until supplementation exceeds 2 grams per day. The
National Academy of Sciences has set a Tolerable Upper Intake Level
(UL) for vitamin B6 of 100 milligrams for adults 19 years and older,
largely based on the issue of imbalanced nervous system activity
described above.
Impact of Cooking, Storage and Processing
How do cooking, storage, or processing affect vitamin B6?
Although historically described as one of the most stable of the B
vitamins, large amounts of vitamin B6 are lost during most forms of
cooking and processing. Loss of B6 from canning of vegetables is
approximately 60-80%; from canning of fruits, about 38%; from freezing
of fruits, about 15%; from conversion of grains to grain products,
between 50-95%; and from conversion of fresh meat to meat by-products,
50-75%.
When food is heated in the context of simple home cooking, the acidity
of the food often determines how much B6 is lost or retained. In
general, the more acidic the food, the poorer the B6 retention. Also,
in the context of the home kitchen, the freezing of foods high in B6
can result in the loss of approximately 1/3 to 1/2 of the total B6
content. Because foods high in B6 are typically not eaten raw, a good
solution to these processing problems is to consume plentiful amounts
of foods high in B6.
Factors that Affect Function
What factors might contribute to a deficiency of vitamin B6?
In addition to dietary insufficiency, smoking and the use of many
prescription medications can contribute to vitamin B6 deficiency.
Medications that deplete the body's supply of B6 are listed in the
medications section of this nutrient profile.
Drug-Nutrient Interactions
What medications affect vitamin B6?
A long list of prescription medications has been linked to depletion
of the body's B6. These medications include birth control pills and
oral estrogens; diuretics, including furosemide; barbiturates,
including phenobarbitol and phenytoin; anti-epileptic drugs, including
carbamazepine; asthma-related drugs, including theophylline;
aminoglycosides, including gentamicin used for bacterial infection;
tuberculosis drugs, including isoniazid and rifampin; and anti-
fibrotic drugs, including beta-aminopropionitrile.
Nutrient Interactions
How do other nutrients interact with vitamin B6?
As a member of the B vitamin family, B6 has key interactions with many
of its family members. B6 is essential for making vitamin B3 (niacin)
from the amino acid tryptophan. In Down's syndrome, for example, some
of the problems related to vitamin B3 deficiency appear to be lessened
by intake of vitamin B6. Vitamins B2 and B3 are both needed to convert
vitamin B6 into its various chemical forms, and imbalances in vitamin
B1 metabolism create imbalances in vitamin B6 metabolism. B6
deficiency can also reduce the body's absorption of vitamin B12.
Health Conditions
What health conditions require special emphasis on vitamin B6?
Vitamin B6 may play a role in the prevention and/or treatment of the
following health conditions::
Cardiovascular system conditions, including atherosclerosis,
hyperhomocysteinemia, and hypertension
Nervous system conditions, including carpal tunnel syndrome,
depression, diabetic neuropathy, autism and epilepsy
Skin conditions, including acne, eczema, and seborrheic dermatitis
Also linked to B6 status are alcoholism, adrenal function, asthma, HIV/
AIDS, kidney stones, PMS, and vaginitis.
Form in Dietary Supplements
What forms of vitamin B6 are found in dietary supplements?
Vitamin B6 is most commonly sold in the form of pyridoxine
hydrochloride (pyridoxine HCl). However, alternative forms of the
vitamin, for example, pyridoxal-5-phophate, are also widely available
and often preferred by healthcare practitioners since they constitute
the biologically active forms of the vitamin.
Individuals who are not experiencing health benefits from
supplementation with pyridoxine hydrochloride, or who have a history
of liver problems that might prevent activation of pyridoxine, should
consider supplementation with pyridoxal-5-phosphate.
Food Sources
Introduction to Nutrient Rating System Chart
The following chart shows the World's Healthiest Foods that are either
excellent, very good or good sources of this nutrient. Next to each
food name you will find the following information: the serving size of
the food; the number of calories in one serving; DV% (percent daily
value) of the nutrient contained in one serving (similar to other
information presented in the website, this DV is calculated for 25-50
year old healthy woman); the nutrient density rating; and the food's
World's Healthiest Foods Rating. Underneath the chart is a table that
summarizes how the ratings were devised. Read detailed information on
our Nutrient Rating System.
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 vitamin B6 (pyridoxine). 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
vitamin B6 (pyridoxine) 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:
vitamin B6 (pyridoxine)
Food Serving
Size Cals Amount
(mg) DV
(%) Nutrient
Density World's
Healthiest
Foods Rating
Spinach, boiled 1 cup 41.4 0.44 22.0 9.6 excellent
Bell peppers, red, raw, slices 1 cup 24.8 0.23 11.5 8.3 excellent
Turnip greens, cooked 1 cup 28.8 0.26 13.0 8.1 excellent
Garlic 1 oz-wt 42.2 0.35 17.5 7.5 very good
Tuna, yellowfin, baked/broiled 4 oz-wt 157.6 1.18 59.0 6.7 very good
Cauliflower, boiled 1 cup 28.5 0.21 10.5 6.6 very good
Cayenne pepper, dried 2 tsp 11.2 0.08 4.0 6.4 good
Mustard greens, boiled 1 cup 21.0 0.14 7.0 6.0 very good
Banana 1 each 108.6 0.68 34.0 5.6 very good
Celery, raw 1 cup 19.2 0.10 5.0 4.7 very good
Cabbage, shredded, boiled 1 cup 33.0 0.17 8.5 4.6 very good
Crimini mushrooms, raw 5 oz-wt 31.2 0.16 8.0 4.6 very good
Asparagus, boiled 1 cup 43.2 0.22 11.0 4.6 very good
Broccoli, steamed 1 cup 43.7 0.22 11.0 4.5 very good
Turmeric, powder 2 tsp 16.0 0.08 4.0 4.5 good
Kale, boiled 1 cup 36.4 0.18 9.0 4.5 very good
Collard greens, boiled 1 cup 49.4 0.24 12.0 4.4 very good
Brussel sprouts, boiled 1 cup 60.8 0.28 14.0 4.1 very good
Watermelon, diced 1 cup 48.6 0.22 11.0 4.1 very good
Cod, baked/broiled 4 oz-wt 119.1 0.52 26.0 3.9 very good
Swiss chard, boiled 1 cup 35.0 0.15 7.5 3.9 very good
Leeks, boiled 0.50 cup 16.1 0.06 3.0 3.3 good
Tomato, ripe 1 cup 37.8 0.14 7.0 3.3 good
Snapper, baked/broiled 4 oz-wt 145.2 0.52 26.0 3.2 good
Carrots, raw 1 cup 52.5 0.18 9.0 3.1 good
Summer squash, cooked, slices 1 cup 36.0 0.12 6.0 3.0 good
Eggplant, cooked, cubes 1 cup 27.7 0.09 4.5 2.9 good
Cantaloupe, cubes 1 cup 56.0 0.18 9.0 2.9 good
Romaine lettuce 2 cup 15.7 0.05 2.5 2.9 good
Potato, baked, with skin 1 cup 133.0 0.42 21.0 2.8 good
Onions, raw 1 cup 60.8 0.19 9.5 2.8 good
Blackstrap molasses 2 tsp 32.1 0.10 5.0 2.8 good
Calf's liver, braised 4 oz-wt 187.1 0.56 28.0 2.7 good
Chicken breast, roasted 4 oz-wt 223.4 0.64 32.0 2.6 good
Halibut, baked/broiled 4 oz-wt 158.8 0.45 22.5 2.6 good
Sweet potato, baked, with skin 1 each 95.4 0.25 12.5 2.4 good
Green peas, boiled 1 cup 134.4 0.35 17.5 2.3 good
Ginger root 1 oz-wt 19.6 0.05 2.5 2.3 good
Turkey breast, roasted 4 oz-wt 214.3 0.54 27.0 2.3 good
Venison 4 oz-wt 179.2 0.43 21.5 2.2 good
Beef tenderloin, lean, broiled 4 oz-wt 240.4 0.49 24.5 1.8 good
Salmon, chinook, baked/broiled 4 oz-wt 261.9 0.52 26.0 1.8 good
Yam (Dioscorea species), cubed, cooked 1 cup 157.8 0.31 15.5 1.8 good
Flaxseeds 2 tbs 95.3 0.18 9.0 1.7 good
Winter squash, baked, cubes 1 cup 80.0 0.15 7.5 1.7 good
Strawberries 1 cup 43.2 0.08 4.0 1.7 good
Avocado, slices 1 cup 235.1 0.41 20.5 1.6 good
Pineapple 1 cup 76.0 0.13 6.5 1.5 good
Grapes 1 cup 61.6 0.10 5.0 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 the current public health recommendations for intake of
vitamin B6?
In 2000, the National Academy of Sciences established Recommended
Dietary Allowances for vitamin B6 for all individuals 1 year and
older, and Adequate Intake (AI) levels for infants under 1 year of
age. These recommendations are as follows:
0-6 months: 100 micrograms
6-12 months: 300 micrograms
1-3 years: 500 micrograms
4-8 years: 600 micrograms
Males 9-13 years: 1.0 milligram
Males 14-50 years: 1.3 milligrams
Males 51 years and older: 1.7 milligrams
Females 9-13 years: 1.0 milligram
Females 14-50: 1.2 milligrams
Females 51 years and older: 1.5 milligrams
Pregnant females of any age: 1.9 milligrams
Lactating females of any age: 2.0 milligrams
References
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Inc., New York, 1998;165,301-304 1988.
Bryan J, Calvaresi E, Hughes D et al. Short-term folate, vitamin B-12
or vitamin B-6 supplementation slightly affects memory performance but
not mood in women of various ages. J Nutr 2002 Jun;132(6):1345-56.
Coleman M, Sobel S, Bhagavan HN, et al. A double-blind study of
vitamin B6 in Down's syndrome infants. Part 1 - clinical and
biochemical results. J Ment Def Res 1985;29:233 1985.
Effersoe H. The effect of topical application of pyridoxine ointment
on the rate of sebaceous secretion in patients with seborrheic
dermatitis. Acta Dermatol 1954;3:272-277 1954.
Fennema OR (Ed.). Food chemistry. Second edition. Marcel Dekker, New
York, 1985 1985.
Groff JL, Gropper SS, Hunt SM. Advanced Nutrition and Human
Metabolism. West Publishing Company, New York, 1995.
Gvozdova LG, Paramanova EG, Goriachenkova EV, et al. The content of
Pyridoxal coenzymes in the blood plasma of patients with coronary
atherosclerosis on a background of therapeutic diet and after
supplemental intake of vitamin B6. Vop Pitan 1966;25:40-44 1966.
Gyorgy P. Developments leading to the metabolic role of vitamin B6. Am
J Clin Nutr 1971;24:1250-1256 1971.
Korpela TK, Christen P (Eds). Biochemistry of vitamin B6. Proceedings
of the 7th International Congress on Chemical and Biological Aspects
of Vitamin B6 Catalysis. Birkhauser Congress Reports, Life Sciences,
Vol. 2, Birkhauser Verlag, Basel, 1987 1987.
Leklem JE. Vitamin B6. In: Machlin LJ (Ed). Handbook of vitamins.
Second edition. Dekker, New York, 1991;341-392 1991.
Merrill AH, Burnham FS. Vitamin B-6. Chapter 18 in: Brown ML (Ed).
Present knowledge in nutrition. Sixth Edition. International Life
Sciences Institute Nutrition Foundation, Washington, DC, 1990;157-159
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National Academy of Sciences. Dietary Reference Intakes: Thiamin,
Riboflavin, Niacin, Vitamin B-6, Vitamin B-12, Pantothenic Acid,
Biotin, and Choline. Institute of Medicine, Food and Nutrition Board,
National Academy of Sciences. Washington, DC, National Academy Press,
1998;390-422 1998.
Ooylan LM, Hart S, Porter KB, Driskell JA et al. Vitamin B-6 content
of breast milk and neonatal behavioral functioning. J Am Diet Assoc
2002 Oct; 102(10):1433-8 2002.
Sauberlich HE. Vitamins - how much is for keeps. Nutr Tod 1980;22:20
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Schaumberg H, Kaplan J, Windebank A, et al. Sensory neuropathy from
pyridoxine abuse. A new megavitamin syndrome. N Engl J Med
1983;309:445-448 1983.
Williams MH. Vitamin and mineral supplements to athletes: do they
help. Clin Sports Med 1984;3:623-637 1984.
Yates AA, Schlicker SA, Suitor CW. Dietary reference intakes: the new
basis for recommendations for calcium and related nutrients, B
vitamins, and choline. J Am Diet Assoc 1998;98:699-706 1998.
© 2001-2007 The George Mateljan Foundation www.whfoods.org
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