Vitamin B6/pyridoxine

Vitamin B6 or pyridoxine is a water soluble vitamin. This vitamin includes three compounds: pyridoxine, pyridoxamine and pyridoxal. All three are converted into pyridoxalphosphate in the organism. This is a vitamin that is an extremely strong acid that decomposes under the influence of both light as well as temperature. Pyridoxine is sometimes also called the anti-dermatological vitamin.

Which foods contain the vitamin?

• Liver
• Salmon
• Egg yolk
• Nuts
• Bread
• Avocado
• Banana

Biological functions of the vitamin

Realised mostly through coenzyme PLP or pyridoxalphosphate.

• Obtaining energy from carbohydrates
• Synthesis of amino acids
• Synthesis of neurotransmitters, heme, nucleotides and sphingomyelins
• Participation in the catabolism of homocysteine
• Participation in the absorption of vitamin B12

Absorption, storage and excretion

All free forms absorb from the small intestine via simple diffusion. Phosphorylated forms, however, dephosphorylate in the gastrointestinal tract before that. Absorption is inhibited by excessive alcohol, coffee, oral contraceptives and cortisol.

In the organism, pyridoxine is stored in small amounts, therefore, the reserves of pyridoxine last for 1–4 weeks.

It is also important to note that this vitamin is also produced by the intestinal microflora.

Since B6 is quite a sensitive vitamin, the reserves of it are considerably decreased in food products that are technologically processed.

Problems resulting from deficiency

• Fatigue
• Irritability
• Mood drops
• Reduction in blood glucose level (insulin sensitivity increases)
• Dermatitis
• Anaemia
• Peripheral neuropathy
• Homocystinuria

Risk groups for developing the deficiency

• Alcoholics (acetaldecyle created from ethanol may act as a competitor of pyridoxine in the formation of compound enzymes)
• Persons with chronic gastrointestinal diseases
• Elderly people
• People with kidney diseases
• Users of oral contraceptives
• Users of isoniazid or penicillamine
• Consumers of excessively protein-rich food

Toxicity

50–500 mg a day with the duration of 1–3 months create peripheral neuropathy and coordination disorders (ataxia) for some women.

In case of continuous administration, large doses (100–500 mg a day) may cause memory disorders because large amounts of pyridoxine have an influence on the effect of dopamine.

Use of vitamin preparations

As an additional treatment component, pyridoxine may also be used for treating alcoholism, stress, obesity, dermatitis, acne, prostatitis, muscular dystrophy, rheumatism, tuberculosis, arthritis, asthma, influenza, kidney stones, hemorrhoids, multiple sclerosis, neuritis, headache, dizziness, Parkinsonism, epilepsy, colitis, anaemia, jaundice, symptoms of depression, rheumatoid arthritis and pregnancy toxicosis (up to 100 mg a day).

To reduce or avoid the premenstrual syndrome, your diet should contain a sufficient amount of pyridoxine. If the sufficient amount of pyridoxine is not obtained with food, additional intake of pyridoxine will also help (50–100 mg a day).

Adequate consumption of pyridoxine protects the organism from both colorectal cancer (rectal cancer) as well as from colorectal adenoma.

The vitamin should be administered together with thiamine, riboflavin, pantothenic acid, vitamin C, zinc, magnesium and manganese.

Figure 1. Vitamin B6: pyridoxine