Authors: The World's Healthiest Foods
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
- Skin disorders including eczema and seborrheic dermatitis
- Convulsions or seizures
Excellent sources of vitamin B6 include bell peppers, summer squash, turnip greens, shiitake mushrooms, and spinach.
For serving size for specific foods, see Nutrient Rating Chart below at the bottom of this page.
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.
Prevention of Unwanted Inflammation
Researchers are not yet clear on the mechanisms involved yet, but repeated studies show that vitamin B6 is required to minimize risk of unwanted inflammation in the body. It's not only the case that ample intake of vitamin B6 is associated with decreased risk of excessive inflammation; it's also the fact that individuals with chronic, excessive inflammation need increased amounts of vitamin B6 in their diet. Unless our dietary intake is sufficient to keep our blood levels of active B6 (pyridoxal-5-phosphate) optimal, we leave ourselves at risk for chronic health problems like type 2 diabetes, cardiovascular disease, and obesity, all of which share a component of chronic, unwanted inflammation.
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.
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.
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.
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.
What foods provide vitamin B6?
Excellent sources of vitamin B6 include summer squash, bell peppers, turnip greens, shiitake mushrooms, and spinach.
Very good food sources of vitamin B6 include garlic, tuna, cauliflower, mustard greens, cabbage, crimini mushrooms, asparagus, broccoli, kale, collard greens, Brussels sprouts, cod, chard, calf's liver, green beans, winter squash, tomatoes, turkey, salmon, and leeks.
Introduction to Nutrient Rating System ChartIn 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. 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 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|
|Summer Squash||1 cup raw||18.1||0.25||12.5||12.4||excellent|
|Spinach||1 cup cooked||41.4||0.44||22.0||9.6||excellent|
|Bell Peppers||1 cup raw||28.5||0.27||13.5||8.5||excellent|
|Turnip Greens||1 cup cooked||28.8||0.26||13.0||8.1||excellent|
|Mushrooms, Shiitake||87 g||29.6||0.25||12.5||7.6||excellent|
|Garlic||1 oz-wt||26.8||0.22||11.0||7.4||very good|
|Cayenne Pepper||2 tsp||11.4||0.09||4.5||7.1||good|
|Tuna||4 oz-wt||157.6||1.18||59.0||6.7||very good|
|Cauliflower||1 cup raw||26.8||0.20||10.0||6.7||very good|
|Mustard Greens||1 cup cooked||21.0||0.14||7.0||6.0||very good|
|Broccoli||1 cup raw||30.9||0.16||8.0||4.7||very good|
|Cabbage||1 cup raw||17.5||0.09||4.5||4.6||good|
|Brussels Sprouts||1 cup raw||37.8||0.19||9.5||4.5||very good|
|Kale||1 cup cooked||36.4||0.18||9.0||4.5||very good|
|Collard Greens||1 cup cooked||49.4||0.24||12.0||4.4||very good|
|Green Beans||1 cup raw||31.0||0.14||7.0||4.1||very good|
|Asparagus||1 cup raw||26.8||0.12||6.0||4.0||very good|
|Romaine Lettuce||2 cups||16.0||0.07||3.5||3.9||good|
|Cod||4 oz-wt||119.1||0.52||26.0||3.9||very good|
|Winter Squash||1 cup baked||75.8||0.33||16.5||3.9||very good|
|Tomatoes||1 cup raw||32.4||0.14||7.0||3.9||very good|
|Swiss Chard||1 cup cooked||35.0||0.15||7.5||3.9||very good|
|Turkey||4 oz-wt||153.1||0.64||32.0||3.8||very good|
|Banana||1 each||105.0||0.43||21.5||3.7||very good|
|Leeks||1 cup raw||54.3||0.21||10.5||3.5||very good|
|Eggplant||1 cup raw||19.7||0.07||3.5||3.2||good|
|Potatoes||1 each baked||160.9||0.54||27.0||3.0||good|
|Sweet Potato||1 cup baked||102.6||0.33||16.5||2.9||good|
|Blackstrap Molasses||2 tsp||32.1||0.10||5.0||2.8||good|
|Onions||1 cup raw||64.0||0.19||9.5||2.7||good|
|Green Peas||1 cup raw||115.7||0.30||15.0||2.3||good|
|Sunflower Seeds||0.25 cup||204.4||0.47||23.5||2.1||good|
|Yam||1 cup baked||157.8||0.31||15.5||1.8||good|
Density>=7.6 AND DV>=10%
|very good||DV>=50% OR
Density>=3.4 AND DV>=5%
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
The Institute of Medicine 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. For more details on this—including its relationship to supplementation—see the Toxicity Symptoms section above.
- Bodwell CE, Erdman JW (Eds). Nutrient interactions. Marcel Dekker, Inc., New York, 1998;165,301-304. 1998.
- 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. 2002.
- 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. 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. 1990.
- Morris MS, Sakakeeny L, Jacques PF et al. Vitamin B-6 intake is inversely related to, and the requirement is affected by, inflammation status. J Nutr. 2010 Jan;140(1):103-10. 2010.
- 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. 1980.
- 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.