Vitamin B6 -Pyridoxine

Question 1

Vitamin B6 - Pyridoxine

Answer 1

Vitamin B6 (pyridoxine) is made up of a group of six related vitamers. Active B6 is involved in over 100 enzymatic reactions. The active forms are pyridoxal 5’ phosphate (PLP) and pyridoxamine phosphate (P5P).

Question 2

Vitamin B6 - Food Sources

Answer 2

• Widely distributed: wholegrains, green vegetables, sunflower seeds, pistachios, walnuts, bananas, lentils, avocados, meat & fish.

Question 3

Vitamin B6 - Bioavailability

Answer 3

Vitamin B6 in a varied diet is approximately 75% bioavailable. Intestinal flora synthesises large amounts but absorption is unknown.

Question 4

Vitamin B6 - Food prep

Answer 4

Processing, preserving, heating and light exposure reduce B6.
Alcohol excess, the OCP and GIT issues increase requirements.

Question 5

Vitamin B6: Roles

Answer 5

Neurotransmitter Production
Red blood cell formation
Methylation
Energy Production

Question 6

Vitamin B6: Neurotransmitter Production - Functions

Answer 6

• Synthesis of:

• GABA
• Dopamine
• Noradrenaline
• Serotonin

Question 7

Vitamin B6: Neurotransmitter Production - Therapeutic uses

Answer 7

• GIT motility (digestion)
• Carpal Tunnel Syndrome
• Morning sickness
• Lactation & PMS

Question 8

Vitamin B6: Red Blood Cell Formation- Functions

Answer 8

• Used for haem production

Question 9

Vitamin B6: Red Blood Cell Formation- Therapeutic Uses

Answer 9

Anaemia

Question 10

Vitamin B6 - Methylation - Functions

Answer 10

Lowers homocysteine

Question 11

Vitamin B6 - Methylation - Therapeutic uses

Answer 11

Cardiovascular disease

Question 12

Vitamin B6 - Energy Production - Functions.

Answer 12

• Amino acid metabolism, releases stored glucose

Question 13

Vitamin B6 - Energy Production - Therapeutic uses

Answer 13

Fatigue

Question 14

Vitamin B6 - Increased need

Answer 14

• Alcohol dependence, long periods of high stress, pregnancy particularly in third trimester, hormonal imbalances, hyperhomocysteinemia (with folate/folic acid and vitamin B12)

Question 15

Vitamin B6 - Deficiency - Signs and Symptoms

Answer 15

• Deficiency is rare , and occurs alongside other deficiencies.
• Symptoms: Low B6 affects the metabolism of fatty acids leading to skin lesions and dermatitis . Tongue inflammation , recurrent mouth ulcers and sores on the corners of the mouth, hormonal imbalance (e.g. PMS), anaemia (fatigue, pallor etc.), depression.

Question 16

Vitamin B6 - Drug Interactions

Answer 16

• Many drugs deplete B6 levels and so intake should be increased.
This includes anticonvulsants, antibiotics, alcohol, chemotherapy drug ‘docetaxel’ and the oral contraceptive pill (OCP).
• Levodopa (Parkinson’s medication ) - the combination of carbidopa and levodopa do not have the B6 depletion problem. However levodopa (on its own) is broken down by B6 so it should not be supplemented (beyond 5-10mg/day).

Question 17

Vitamin B6 - Toxicity

Answer 17

• 100-200mg/day supplements long term can lead to toxicity symptoms including neuropathy, acne, headache, nausea.