Vitamin B6

by Mary Calvagna, MS

Vitamin B6 is a water-soluble vitamin. Water-soluble vitamins are stored in the body in limited amounts. Because they are excreted through the urine, it is a good idea to have them in your daily diet.

Functions

Vitamin B6's functions include:

Helping with amino acid and protein metabolism
Enabling red blood cell metabolism
Helping the nervous system function efficiently
Helping the immune system function efficiently
Converting tryptophan (an amino acid) to niacin (a vitamin)
Enabling the breakdown of glycogen to glucose
Aiding in the metabolism, transportation, and distribution of selenium
Assisting in the metabolism of calcium and magnesium

Recommended Intake:

Age Group (in years)	Recommended Dietary Allowance
Age Group (in years)	Females	Males
1-3	0.5 milligrams (mg)	0.5 mg
4-8	0.6 mg	0.6 mg
9-13	1.0 mg	1.0 mg
14-18	1.2 mg	1.3 mg
19-50	1.3 mg	1.3 mg
Pregnancy	1.9 mg	n/a
Lactation	2.0 mg	n/a
51 +	1.5 mg	1.7 mg

Vitamin B6 Deficiency

Primary deficiency of vitamin B6 is rare—most foods contain the vitamin. Secondary deficiency may result in certain situations, including malabsorption, alcoholism, some medications, and cigarette smoking. Symptoms of vitamin B6 deficiency include:

Skin inflammation and irritation
Glossitis—sore or inflamed tongue
Confusion
Depression
Irritability and nervousness
Cheilosis—cracking and scaling of the lips (including the corners of the mouth)
Convulsions—especially in newborns
Anemia

Vitamin B6 Toxicity

The tolerable upper intake level (UL) for vitamin B6 from dietary sources and supplements combined is 100 mg per day for adults. Symptoms of vitamin B6 toxicity include:

Poor coordination
Nausea
Skin sores
Sensitivity to sunlight

Major Food Sources

Food	Serving Size	Vitamin B6 Content (mg)
Breakfast cereal, fortified 25%	¾ cup	0.5 (check Nutrition Facts label)
Beef liver, pan fried	3 ounces	0.9
Potato, boiled	1 cup	0.4
Banana	1 medium	0.4
Chicken breast, roasted, no skin	3 ounces	0.5
Chickpeas, canned	1 cup	1.1
Turkey, meat only, roasted	3 ounces	0.4
Ground beef, 85% lean	3.0 ounces	0.3
Spaghetti sauce	1 cup	0.4
Waffles, ready to heat	1 waffle	0.3
Mixed nuts, dry roasted	1 ounce	0.1
Rice, white, enriched	1 cup	0.1
Tuna, fresh	3 ounces	0.9
Raisins, seedless	½ cup	0.1
Spinach, frozen, boiled	½ cup	0.1
Tofu, raw	½ cup	0.1

Health Implications

Populations at Risk for Vitamin B6 Deficiency

The following populations may be at risk for vitamin B6 deficiency and may require a supplement:

People who consume excessive amounts of alcohol
People with poor kidney function
People with autoimmune disorders, such as rheumatoid arthritis, celiac disease, and ulcerative colitis

Vitamin B6, Homocysteine, and Heart Disease

Homocysteine is an amino acid normally found in the blood. Studies have shown that elevated blood levels of homocysteine can be a risk factor for heart disease and stroke. Because vitamins B6, B12, and folic acid are required for the metabolism of homocysteine, it is thought that a deficiency of any of the 3 may increase the level of homocysteine in the blood. Studies have failed to show that taking these vitamins as supplements in people with normal levels offers protection from heart disease.

Morning Sickness

There is evidence that high levels of B6 can help alleviate the symptoms of morning sickness during pregnancy.

Areas of Research That Have Not Been Supported by Clinical Data

Premenstrual syndrome (PMS) —There has been much anecdotal evidence that vitamin B6 can help relieve the symptoms of PMS—depression, irritability, bloating, mastalgia. However, clinical trials have failed to support this idea.
Carpal tunnel syndrome —There is no evidence to support the idea that B6 can ease carpal tunnel syndrome.

Tips for Increasing Your Vitamin B6 Intake

To help increase your intake of vitamin B6:

Sprinkle kidney beans or garbanzo beans on a salad
Opt for a fortified breakfast cereal—one that is high in fiber—in the morning
Slice a banana into your oatmeal or cereal
If you take a vitamin supplement, make sure it contains vitamin B6

RESOURCES:

Eat Right—Academy of Nutrition and Dietetics
http://www.eatright.org

American Society for Nutrition
http://www.nutrition.org

CANADIAN RESOURCES:

Dietitians of Canada
http://www.dietitians.ca

Health Canada
http://www.hc-sc.gc.ca

References:

Homocysteine and cardiovascular disease. EBSCO DynaMed website. Available at:
...(Click grey area to select URL)
Updated October 5, 2015. Accessed March 17, 2016.

Pyridoxine. EBSCO DynaMed website. Available at:
...(Click grey area to select URL)
Updated March 14, 2016. Accessed March 17, 2016.

Vitamin B6. EBSCO Natural and Alternative Treatments website. Available at:
...(Click grey area to select URL)
Updated December 15, 2015. Accessed March 17, 2016.

Vitamin B6. National Institutes of Health Office of Dietary Supplements website. Available at: https://ods.od.nih.gov/factsheets/VitaminB6-HealthProfessional. Updated February 11, 2016. Accessed March 17, 2016.

Last reviewed March 2016 by Michael Woods, MD
Last Updated: 3/17/2016

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