Vitamin B6
Definition
Vitamin B6 is a water-soluble vitamin. Water-soluble vitamins dissolve in water so the body cannot store them. Leftover amounts of the vitamin leave the body through the urine. Although the body maintains a small pool of water-soluble vitamins, they have to be taken regularly.
Lack of vitamin B6 in the body is uncommon. It can occur in people with kidney failure, liver disease, or alcohol dependence.
Alternative Names
Pyridoxal; Pyridoxine; Pyridoxamine
Function
Vitamin B6 helps the body to:
- Make antibodies. Antibodies are needed to fight many viruses, infections, and other diseases.
- Maintain normal nerve function.
- Make hemoglobin. Hemoglobin carries oxygen in the red blood cells to the tissues. A vitamin B6 deficiency can cause a form of anemia.
- Break down proteins. The more protein you eat, the more vitamin B6 you need.
- Keep blood sugar (glucose) in normal ranges.
Food Sources
Vitamin B6 is found in:
- Tuna and salmon
- Banana
- Legumes (dried beans)
- Beef and pork
- Nuts
- Poultry
- Whole grains and fortified cereals
- Chickpeas
Fortified breads and cereals may also contain vitamin B6. Fortified means that a vitamin or mineral has been added to the food.
Side Effects
Large doses of vitamin B6 can cause:
- Difficulty coordinating movement
- Numbness
- Sensory changes
Deficiency of this vitamin can cause:
- Confusion
- Depression
- Irritability
- Mouth and tongue sores also known as glossitis
- Peripheral neuropathy
(Vitamin B6 deficiency is not common in the United States.)
Recommendations
Recommendations for vitamin B6, as well as other nutrients, are provided in the Dietary Reference Intakes (DRIs) developed by the Food and Nutrition Board at the National Academies of Sciences, Engineering, and Medicine. DRI is a term for a set of reference intakes that are used to plan and assess the nutrient intakes of healthy people. These values, which vary by age and sex, include:
Recommended Dietary Allowance (RDA): The average daily level of intake that is enough to meet the nutrient needs of nearly all (97% to 98%) healthy people. An RDA is an intake level based on scientific research evidence.
Adequate Intake (AI): This level is established when there is not enough scientific research evidence to develop an RDA. It is set at a level that is thought to ensure enough nutrition.
Dietary reference intakes for vitamin B6:
Infants (AI)
- 0 to 6 months: 0.1 milligrams per day (mg/day)
- 7 to 12 months: 0.3 mg/day
Children (RDA)
- 1 to 3 years: 0.5 mg/day
- 4 to 8 years: 0.6 mg/day
- 9 to 13 years: 1.0 mg/day
Adolescents and adults (RDA)
- Males age 14 to 50 years: 1.3 mg/day
- Males over 50 years: 1.7 mg/day
- Females age 14 to 18 years: 1.2 mg/day
- Females age 19 to 50 years: 1.3 mg/day
- Females over 50 years: 1.5 mg/day
- Females of all ages 1.9 mg/day during pregnancy and 2.0 mg/day during lactation
The best way to get the daily requirement of essential vitamins is to eat a balanced diet that contains a variety of foods.
References
Litwack G. Vitamins and nutrition. In: Litwack G, ed. Human Biochemistry. 2nd ed. Philadelphia, PA: Elsevier; 2022:chap 20.
Mason JB, Booth SL. Vitamins, trace minerals, and other micronutrients. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 205.
Markell M, Siddiqi HA. Vitamins and trace elements. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Philadelphia, PA: Elsevier; 2022:chap 27.
National Institutes of Health website. Vitamin B6: fact sheet for health professionals. ods.od.nih.gov/factsheets/VitaminB6-HealthProfessional/. Updated June 2, 2022. Accessed February 21, 2023.
Reviewed By: Stefania Manetti, RD/N, CDCES, RYT200, My Vita Sana LLC - Nourish and heal through food, San Jose, CA. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
All rights reserved.