Vitamin B6

Inhaltsstoff-Glossar

Vitamin B6

What is vitamin B6?

Vitamin B6 is the collective name for several related compounds, including pyridoxine, pyridoxal and pyridoxamine. Their active coenzyme form is pyridoxal 5'-phosphate, often abbreviated as PLP.

Vitamin B6 is involved in more than one hundred enzymatic reactions, particularly in amino-acid and protein metabolism.

Where does vitamin B6 occur naturally?

Vitamin B6 is found in both animal and plant foods. Good sources include:

  • Fish and poultry
  • Liver
  • Potatoes
  • Bananas
  • Whole grains
  • Legumes
  • Nuts

Because vitamin B6 is present in many foods, severe deficiency is uncommon in people eating a varied diet.

What functions does vitamin B6 have?

Vitamin B6 contributes to:

  • Normal energy-yielding metabolism
  • Normal protein and glycogen metabolism
  • Normal functioning of the nervous system
  • Normal psychological function
  • Normal red-blood-cell formation
  • Normal homocysteine metabolism
  • Normal immune function
  • Reduction of tiredness and fatigue
  • Regulation of hormonal activity

Because vitamin B6 is central to amino-acid metabolism, requirements are influenced partly by protein intake and turnover.

Recommended intake

European and German nutritional authorities generally recommend daily intakes in the low milligram range for healthy adults. Exact recommendations vary by age, sex, pregnancy and breastfeeding.

Average intake in the general population is often adequate, but individual deficiency risk may be higher in certain groups.

Who is at risk of deficiency?

Risk groups include:

  • People with chronic high alcohol intake
  • Older adults with low food intake
  • People with kidney disease
  • People with severe underweight or malnutrition
  • Smokers
  • People taking selected medicines

Symptoms of deficiency may include dermatitis, anemia, irritability, confusion, weakened immune function and neurological complaints.

Vitamin B6 and research

Researchers have studied vitamin B6 in relation to cardiovascular disease, depression, cognition, cancer and weight management.

Adequate vitamin B6 intake from food is associated with normal metabolic function. However, evidence that high-dose supplementation prevents chronic disease is inconsistent.

Some studies have examined combinations of leucine and vitamin B6 in overweight adults. Certain trials reported modest changes in fat oxidation or body composition, but supplements cannot replace a calorie-controlled diet, adequate protein and physical activity.

Can too much vitamin B6 be harmful?

Vitamin B6 has relatively low acute toxicity, but long-term high-dose use can damage sensory nerves. Symptoms may include tingling, numbness, impaired coordination and difficulty walking.

Neuropathy has been reported after months of taking high doses. For this reason, upper intake limits have been established and have been revised downward in Europe as safety data have evolved.

People should avoid taking multiple products containing vitamin B6 without calculating the total daily amount.

Conclusion

Vitamin B6 is essential for protein metabolism, nervous-system function, blood formation and immune function. Most people can meet their needs through food. Supplementation is useful when intake is inadequate or deficiency risk is increased, but long-term high doses can cause nerve damage.

Sources