For serving size for specific foods see the Nutrient Rating Chart.

Basic Description Role in Health Support Summary of Food Sources Nutrient Rating Chart Impact of Cooking, Storage and Processing Risk of Dietary Deficiency Other Circumstances that Might Contribute to Deficiency

Relationship with Other Nutrients Risk of Dietary Toxicity Disease Checklist Public Health Recommendations References

Basic Description

Vitamin B6 is a water-soluble vitamin that is found in a variety of forms in the foods we eat as well as in our bodies. These forms include pyridoxal 5'-phosphate (PLP), which appears to be the most active form as a human vitamin. Other forms include pyridoxal (PL), pyridoxamine (PM), pyridoxine (PN), pyridoxamine 5'-phosphate (PMP) and pyridoxine-5'-phosphate (PNP). Nearly half of all WHFoods provide you with measurable amounts of vitamin B6. In addition, you can find nearly 30 excellent or very good sources of this nutrient among our core 100 WHFoods.

There has been substantial debate about blood levels of vitamin B6 and their relationship both to dietary intake and overall health. This debate has centered around the fact that a person can consume the recommended dietary amount of vitamin B6 (our WHFoods recommended level is 1.7 milligrams) and yet have a blood level of vitamin B6 (in the form of plasma PLP) that may not be optimal for metabolism. While we continue to recommend the highest adult Dietary Reference Intake (DRI) level for B6 as established by the National Academy of Sciences, we recognize that this amount might eventually be revised upward based on future research in this area. We would also note that the Tolerable Upper Limit (UL) for vitamin B6 is set at a relatively high level of 100 milligrams for adults, allowing plenty of room for B6 intake substantially above the DRI level.

Role in Health Support

Production of Red Blood Cells

Hemoglobin is complicated protein present in red blood cells, and one of its primary roles is to help carry oxygen around the body. Heme is a key section of the hemoglobin molecule and the initial production of heme in bodies requires the presence of vitamin B6. (Although heme production can occur in multiple places throughout the body, the primary places involve the liver and bone marrow.) The importance of vitamin B6 in red blood cell production is underscored by relatively rare types of anemia called sideroblastic anemias.

Metabolism of Carbohydrates

Vitamin B6 is involved at several steps in the metabolism of carbohydrates. In particular, the enzyme that pulls carbohydrates out of storage in the cell (in the form of a molecule called glycogen) requires vitamin B6 for its activity.

While nobody would do an experiment like this in humans, researchers have been able to induce problems in carbohydrate metabolism by feeding rats diets deficient in vitamin B6. Since breakdown of carbohydrates is an ongoing process that occurs in our bodies throughout the day to help us sustain our physical energy level, daily consumption of whole foods rich in B6 also makes good sense for maintaining ongoing energy levels.

Brain and Nervous System Health

Vitamin B6 is one of several B vitamins required for proper production of messaging molecules in our nervous system and brain (called neurotransmitters). Three key neurotransmitters—namely GABA, dopamine, and serotonin—all require vitamin B6 for synthesis.

Just as an example of how important this nutrient can be to proper brain and nervous system, function, there is a condition called pyridoxine-dependent epilepsy where a genetic mutation interferes with normal vitamin B6 function. In people who have this mutation, the brain does not develop properly and epileptic seizures are experienced beginning in infancy. Luckily, this condition is rare.

However, we may be at risk of other more common problems that can be brain and nervous-system related if our B6 intake is poor. Depression is a good example in this area. Researchers in Japan have found that the risk of depressed mood is higher in people with lower levels of vitamin B6 in their diet (in comparision with the general population). Another research group concluded that this link between risk of depression and B6 intake becomes even stronger when dietary folic acid—a nutrient that works very closely with vitamin B6 in brain and nervous system chemistry—is deficient as well. Recent research has also begun to indicate a link between B6 deficiency and risk of development for attention deficit disorder (ADHD). So once again, we are looking at the possible widespread importance of B6 for brain and nervous system support.

Liver Detoxification

Generally speaking, we remove unwanted chemicals from our blood in the liver and kidney, and this process involves two steps. The first of these two steps is to make the chemicals more water soluble to allow for the second step of binding and removal. The number of nutrients required for this first step is long, but vitamin B6 is clearly one of the most important. It is so important that researchers can induce liver dysfunction in animals by feeding them a pyridoxine-depleted diet.

Other Health Support Roles

Preliminary research on inflammation-related chronic diseases has shown likely connections between the risk of these diseases and B6 deficiency. Interestingly, in addition to increased risk of these conditions in association with B6 deficiency, the presence of chronic inflammatory conditions also appears to be associated with depletion of vitamin B6.

In animal studies, B6 has been shown to play a role in the development of healthy immune system function. This potential health benefit from B6 appears to be associated with its role in metabolism of the amino acid tryptophan.

As mentioned earlier, B6 plays a well-researched role in the synthesis and metabolism of certain nervous system messaging molecules. While we emphasized the nervous system aspects of this health support role earlier in this section, we would also like to point out that the messaging molecules pathways described earlier involve specific amino acids (building blocks of protein), making B6 a potentially important vitamin for support of general amino acid and protein-related metabolism. Interestingly, many of our WHFoods that rank as excellent or very good sources of protein also rank as excellent or very good sources of B6. This overlap may not be a coincidence, given the role played by B6 in protein and amino acid metabolism. It is also worth mentioning that diets especially high in protein may increase risk of B6 depletion, even though many protein-rich foods are also rich in B6. The reason for this risk involves differing nutrient concentrations in which the concentration of protein in a particular food might be significantly greater than the concentration of B6. While this difference might not be important at ordinary protein intakes, unusually high intakes (for example, intakes well over 100 grams) might make the difference more of an issue.

Summary of Food Sources

We see an unusually wide variety of foods listed as good to excellent sources of vitamin B6. As mentioned earlier, nearly half of our WHFoods fall into this category. Plant and animal foods are both well represented. In our top sources by nutrient richness, we see leafy and root vegetables, along with fruit, fish, and fowl. This variety will allow for many choices for a B6-rich diet plan.

With the exception of tuna, all of our excellent sources of vitamin B6 are vegetables. As with so many other nutrients, our discussion of B6-rich foods starts here. We encourage having at least a serving of greens most days, if not every day, along with several other minimally cooked fresh vegetables. And we encourage you not to skimp on the amount, but to consider having 1-1/2 cups in a serving.

In the non-plant category, we have one excellent source of B6 in tuna, and several very good source in beef, chicken, and salmon. And if we continue on into the good category, we pick up shrimp and cod as well.

Some, but not all, fruits are strong sources of vitamin B6. Bananas, pineapples, and avocados are all good to very good sources of this nutrient.

A number of legumes contain between 10-30% of the DRI for vitamin B6 per serving and can be good contributors toward your intake goal. Similarly, a number of the whole grains contain 10-20% of the DRI and can help to build up your daily vitamin B6 nutrition.

Nutrient Rating Chart

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. 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.

Impact of Cooking, Storage and Processing

The pyridoxine form of vitamin B6 found in foods tend to be fairly stable to storage. It takes approximately one year for about 25% of the B6 in various foods to be lost, and even though this amount is relatively high, there are no foods that we recommend storing for this prolonged period of time. In fact, most of the WHFoods that rank as excellent or very good sources of B6 are foods that we recommend be consumed as fresh as possible.

Prolonged exposure to heat can degrade vitamin B6 in most foods. Perhaps as a result of the difference in structural forms, we see more degradation of this vitamin in animal meats than in vegetables.

Both steaming and boiling result in relatively low amounts of B6 loss. We've see research on Brussels sprouts, for example, showing 10-20% loss of B6 based on these two cooking methods. (As in most research on steaming and boiling, boiling in this study resulted in greater B6 loss than steaming, presumably because of submersion in water allowing more surface-to-water contact with the Brussels sprouts.)

Perhaps counterintuitively, lower pH tends to stabilize the vitamin under heat. So adding a little vinegar or tomato into a sauce, for example, may help keep the vitamin B6 more intact.

Risk of Dietary Deficiency

Based on National Health and Nutrition Examination Survey (NHANES) data from 2009-2010, average intake of vitamin B6 for men and women 20 years and older —as well as all U.S. citizens ages 2 and older—was above our WHFoods recommended daily intake level for B6 of 1.7 milligrams.

As mentioned earlier in this article, however, there has been significant debate in the clinical research over the relationship between blood levels of vitamin B6 and overall health, and it is possible that consumption of the DRI level for B6 may not support optimal blood levels of the PLP form of this vitamin. Exactly how this specific area of clinical research relates to overall B6 deficiency risk is an area of research that will be important to follow in future studies.

Other Circumstances that Might Contribute to Deficiency

Women who take oral contraceptive pills (OCP) have an increased risk of vitamin B6 deficiency. According to one research group, 40% of OCP users have biochemical evidence for deficiency, a number much greater than would be predicted based on diet alone.

OCP are not unique in their ability to lead to loss of vitamin B6. A number of other medications have been reported to have this effect, including steroids, antibiotics, and drugs used to treat Parkinson's disease.

Even at a consistent dietary intake, people over the age of 65 years show lower blood levels of vitamin B6. There are several proposed explanations for this phenomenon, including decreased absorption, more difficulty activating the vitamin to its most active form, and increased breakdown. Regardless of the cause, older people may need to pay special attention to dietary vitamin B6 intake. In fact, the highest DRI set for B6 by the National Academy of Sciences (other than the DRIs related to pregnancy and lactation) is the DRI for older men of 1.7 milligrams.

Relationship with Other Nutrients

The B complex of vitamins works as a team in carbohydrate metabolism, and deficiency of one can affect the whole process in a detrimental way. Because vitamin B6 deficiency is more likely than most of the other B vitamins, it should be a particular focus in making sure that this energy generation process occurs smoothly.

In particular, folic acid and vitamin B12 are intimately related to vitamin B6 in their core biochemical pathways. Each of these is a nutrient with potential for dietary deficiency, each can be prone to damage or absorption problems, and each comes from different food types. We get vitamin B12 from a relatively small number of foods (primarily animal and fermented foods), folic acid predominantly from vegetables and legumes, and vitamin B6 from many food groups. Enjoyment of food diversity is clearly an ideal way.

Every reaction in your body that uses vitamin B6 also uses magnesium as a mineral co-factor. Like vitamin B6, magnesium is a nutrient that many Americans fail to eat enough of on a regular basis. Tuna, spinach, and pumpkin seeds are all examples of foods rich in both vitamin B6 and magnesium. Our Chicken Breast With Honey-Mustard Sauce recipe contains more than the RDA for vitamin B6 and 85% of the requirement for magnesium.

Diets very high in protein are known to increase risk of vitamin B6 depletion. . For this reason, some researchers have suggested increased B6 when protein intake is especially high. For example, we have seen one research study in which researchers recommended nearly double the DRI for B6 with intake of 150 grams of protein per day by young women. Our conclusions from this research are two-fold: first, it does not make sense to consume excessive amounts of protein, unless specifically following a medical food regimen or under other specific health-related circumstances. Second, if you are consuming especially high levels of protein, it makes sense to take a closer look at your B6 intake and make sure that you are focusing on whole foods equally right in protein and B6.

Risk of Dietary Toxicity

At amounts above the Tolerable Upper Intake Level (UL) of 100 mg per day, vitamin B6 has been reported to cause changes in sensation in the hands and feet. Given that even the 95th percentile of vitamin B6 intake in the U.S. is less than 10 mg per day, reaching 100 mg on a regular basis from foods alone is very unlikely. In fact, every report of vitamin B6 toxicity that we can find involved the use of mega-dose supplementation. We find no reason to be concerned about the health effects of diets rich in vitamin B6, even when this dietary richness involves 200%-500% of the recommended DRI level.

Disease Checklist

• Premenstrual syndrome
• Fibrocystic breast disease
• Anemia
• Carpal tunnel syndrome
• Morning sickness
• Asthma
• High homocysteine
• Epilepsy
• Depression
• Seborrheic dermatitis
• ADHD

Public Health Recommendations

In 1998, the National Academy of Sciences established a set of Dietary Reference Intakes (DRI) that contained Recommended Dietary Allowances (RDA) for vitamin B6 by age and gender. These are summarized in the chart below. Note that the recommendations for infants under one year are Adequate Intake (AI) standards. The RDAs and AIs are as follows:

• 0-6 months: 0.1 mg
• 6-12 months: 0.3 mg
• 1-3 years: 0.5 mg
• 4-8 years: 0.6 mg
• 9-13 years: 1.0 mg
• 14-18 years, female: 1.2 mg
• 14-18 years, male: 1.3. mg
• 19-50 years, female: 1.3 mg
• 19-50 years, male: 1.3 mg
• 50+ years, female: 1.5 mg
• 50+ years, male: 1.7 mg
• Pregnant women: 1.9 mg
• Lactating women: 2.0 mg

The Tolerable Upper Intake Limit (UL) for vitamin B6 is set at 100 mg. Given that most foods contain less than a milligram of vitamin B6 per serving, reaching this level of intake without the use of supplements appears impossible. Intakes of vitamin B6 as high as 200-500% of the DRI still fall far below this UL guideline and have no research basis for any concern.

The Daily Value (DV) for vitamin B6 intake is 2 mg per day per 2000 calories. This is the value found on food labels.

As our WHFoods recommended daily intake level for B6, we chose the highest adult DRI level of 1.7 milligrams.

References

• Cellini B, Montioli R, Oppici E, et al. The chaperone role of the pyridoxal 5'-phosphate and its implications for rare diseases involving B6-dependent enzymes. Clin Biochem. 2014 Feb;47(3):158-65. doi: 10.1016/j.clinbiochem.2013.11.021.
• Combs GF. Vitamin B6. In: The Vitamins. Academic Press, Waltham, MA, 2007.
• Food and Nutrition Board, Institute of Medicine. Dietary reference intakes for thiamin, riboflavin, niacin, vitamin B6, folate, vitamin B12, pantothenic acid, biotin, and choline. Washington, DC: National Academy Press; 1998;58-86.
• Dolina S, Margalit D, Malitsky S, et al. Attention-deficit hyperactivity disorder (ADHD) as a pyridoxine-dependent condition: Urinary diagnostic biomarkers
• Medical Hypotheses, Volume 82, Issue 1, January 2014, Pages 11—116.
• Gregory JF, Park Y, Lamers Y, et al. Metabolomic analysis reveals extended metabolic consequences of marginal vitamin B6 deficiency in healthy human subjects. PloS One 2013;8:e63544.
• Hochberg M, Melnick D, Oser BL. On the stability of pyridoxine. J Biol Chem 1944;155:129-36.
• Inubushi T, Okada M, Matsui A, et al. Effect of dietary vitamin B6 contents on antibody production. Biofactors. 2000;11(1-2):93-6.
• Kretsch MJ, Sauberlich HE, Skala JH, et al. Vitamin B6 requirement and status assessment: young women fed a depletion diet followed by a plant- or animal-protein diet with graded amounts of vitamin B6. Am J Clin Nutr 1995;61:1091-101.
• Leskova E, Kubikova J, Kovacikova E, et al. Vitamin losses: Retention during heat treatment and continual changes expressed by mathematical models. J Food Comp Anal 2006;19:252-76.
• Lussana F, Zighetti ML, Bucciarelli P, et al. Blood levels of homocysteine, folate, vitamin B6 and B12 in women using oral contraceptives compared to non-users. Thromb Res 2003;112:37-41.
• Matte JJ, LeFloc'h N, Primot Y, et al. Interaction between dietary tryptophan and pyridoxine on tryptophan metabolism, immune responses and growth performance in post-weaning pigs. Animal Feed Science and Technology, Volume 170, Issues 3—4, 22 December 2011, Pages 256-264.
• Morris MS, Sakakeeny L, Jacques PF, et al. Vitamin B-6 Intake Is Inversely Related to, and the Requirement Is Affected by, Inflammation Status. The Journal of Nutrition; Jan 2010; 140, 1; 103-110.
• Morris MS, Picciano MF, Jacques PF, et al. Plasma pyridoxal 5'-phosphate in the US population: the National Health and Nutrition Examination Survey, 2003-4. Am J Clin Nutr 2008;87:1446-54.
• Nanri A, Pham NM, Kurotani K, et al. Serum pyridoxal concentrations and depressive symptoms among Japanese adults: results from a prospective study. Eur J Clin Nutr 2013;67:epub ahead of print.
• Pan WH, Chang YP, Yeh WT, et al. Co-occurrence of anemia, marginal vitamin B6, and folate status and depressive symptoms in older adults. J Geriatr Psychiatry Neurol. 2012;25:170-8.
• Skodda S, Muller T. Refractory epileptic seizures due to vitamin B6 deficiency in a patient with Parkinson's disease under duodopa therapy. J Neural Transm 2013;120:315-8.
• Zhao M, Lamers Y, Ralat MA, et al. Marginal vitamin B6 deficiency decreases plasma (n-3) and (n-6) PUFA concentrations in healthy men and women. J Nutr 2012;142:1791-7.