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

Functions

Vitamin B6's functions include:

  • Helping 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
FemalesMales
1-30.5 milligrams (mg)0.5 mg
4-80.6 mg0.6 mg
9-131.0 mg1.0 mg
14-181.2 mg1.3 mg
14-18 Pregnancy1.9 mgn/a
14-18 Lactation2.0 mgn/a
19-501.3 mg1.3 mg
19-50 Pregnancy1.9 mgn/a
19-50 Lactation2.0 mgn/a
51 +1.5 mg1.7 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 medicines, and cigarette smoking. Symptoms of vitamin B6 deficiency include:

  • Skin inflammation and irritation
  • Glossitis (sore or inflamed tongue)
  • Confusion
  • Depression
  • Irritability and nervousness
  • Fatigue and sleepiness
  • Cheilosis (cracking and scaling of the lips)
  • Convulsions
  • Anemia

Vitamin B6 Toxicity

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

  • Muscle incoordination
  • Numbness of the hands and feet
  • Impaired reflexes
  • Abnormal plasma amino acid levels

Major Food Sources

FoodServing Size Vitamin B6 Content
(mg)
Fortified breakfast cereal¾ cup 2.00
(check Nutrition Facts label)
Oatmeal, instant1 packet0.42
Potato, baked with skin1 medium0.70
Banana1 medium 0.68
Chicken breast, roasted, no skin3.5 ounces0.52
Garbanzo beans, canned½ cup0.57
Tomato juice, canned6 oz0.20
Pork loin, lean3.0 ounces0.42
Roast beef, lean3.5 ounces0.32
Rainbow trout, cooked3 ounces0.29
Sunflower seeds, dry roasted1 ounce0.23
Avocado½ cup0.20
Tuna, canned in water3 ounces0.18
Peanut butter2 Tbs0.15
Lima beans, cooked½ cup0.10
Soybeans, cooked½ cup0.05

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:

  • The Elderly—Many older adults have low blood levels of vitamin B6, which may occur from low intake of the vitamin or accelerated hydrolysis and oxidation of the vitamin.
  • People Who Consume Excessive Amounts of Alcohol—Alcohol impairs the conversion and enhances the hydrolysis of the vitamin.

Vitamin B6, Homocysteine, and Heart Disease

Homocysteine is an amino acid normally found in the blood. However, 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 three may increase the level of homocysteine in the blood. One would think that taking these vitamins as supplements may offer protection from heart disease. However, clinical trials do not support this idea.

Areas of Research That Have Not Been Supported by Clinical Data

  • Headache and Depression—Vitamin B6 is needed for the synthesis of neurotransmitters, including serotonin. Low levels of serotonin have been found in individuals suffering from depression and migraine headaches. This led researchers to look at the relationship between vitamin B6, headaches, and depression. So far, vitamin B6 supplements have not proved effective in relieving either.
  • 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.
  • Morning Sickness—There has been some evidence that high levels of B6 can help allieviate the symptoms, such as nausea, of morning sickness during pregnancy.

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