Vitamin B6

Foods naturally containing vitamin b6, including bananas, salmon, liver, tuna, chickpeas, poultry, dark leafy greens, bananas

Vitamin B6, or pyridoxine, is a water-soluble vitamin found naturally in many foods, as well as added to foods and supplements. Pyridoxal 5’ phosphate (PLP) is the active coenzyme form and most common measure of B6 blood levels in the body. PLP is a coenzyme that assists more than 100 enzymes to perform various functions, including the breakdown of proteins, carbohydrates, and fats; maintaining normal levels of homocysteine (since high levels can cause heart problems); and supporting immune function and brain health. 

Recommended Amounts

 RDA: The Recommended Dietary Allowance (RDA) for men ages 14-50 years is 1.3 mg daily; 51+ years, 1.7 mg. The RDA for women ages 14-18 years is 1.2 mg; 19-50 years, 1.3 mg; and 51+ years, 1.5 mg. For pregnancy and lactation, the amount increases to 1.9 mg mcg and 2.0 mg, respectively. [1]

UL: A Tolerable Upper Intake Level (UL) is the maximum daily dose unlikely to cause adverse side effects in the general population. The UL for adults 19 years and older is 100 mg daily, with slightly lesser amounts in children and teenagers. This amount can only be achieved by taking supplements. Even higher amounts of vitamin B6 supplements are sometimes prescribed for medical reasons, but under the supervision of a physician as excess vitamin B6 can cause toxicity. [1,2]

Vitamin B6 and Health

Vitamin B6 has been widely studied for its role in disease prevention. The vitamin in supplement form shows the most promise for the treatment of pregnancy-induced nausea, but such use should only occur under the supervision of a physician. Adequate blood levels of B6 may be associated with lower risk of cancers, compared to low blood levels. However, the use of separate B6 supplements (apart from the RDA amounts in typical multivitamin preparations) is inconclusive and not recommended.

Food Sources

Vitamin B6 is found in a variety of animal and plant foods.

Signs of Deficiency and Toxicity

Deficiency 

A vitamin B6 deficiency most often occurs when other B vitamins in the body are low, particularly vitamin B12 and folic acid. A mild deficiency may have no symptoms, but a more severe or prolonged deficiency can exhibit the following:

  • Microcytic anemia
  • Skin conditions
  • Depression
  • Confusion
  • Lowered immunity

Certain conditions can increase the risk of developing a deficiency by interfering with the absorption of vitamin B6:

  • Kidney disease
  • Autoimmune intestinal disorders like celiac disease, ulcerative colitis, and Crohn’s disease
  • Autoimmune inflammatory disorders such as rheumatoid arthritis
  • Alcoholism

Toxicity  

It is quite unlikely to reach a toxic level of vitamin B6 from food sources alone. Vitamin B6 is a water-soluble vitamin so that unused amounts will exit the body through the urine. [2] However, a toxic level can occur from long-term very high dose supplementation of greater than 1,000 mg daily. [1] Symptoms usually subside after stopping the high dosage. Symptoms include:

  • Neuropathy in feet and hands
  • Ataxia (loss of control of body movements)
  • Nausea

Related

B Vitamins
Vitamins and Minerals

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