VITAMIN B6 (Pyridoxine)
Vitamin B6 comes in several forms:
– pyridoxamine (and add a -5-phosphate molecule to the above three).
Humans cannot make this vitamin so it is an essential nutrient that must come from the diet. The pyridoxal-5-phosphate form of B6 is involved in about 100 enzyme reactions including:
– Releasing glucose stored in glycogen by glycogen phosphorylase
– Creating glucose from amino acids in gluconeogenesis
– Creating neurotransmitters: dopamine, norepinephrine, serotonin and gamma-aminobutryric acid
– Formation of heme in red blood cells
– Formation of the vitamin niacin from tryptophan
– Formation of nucleic acids (DNA and RNA)
– Conversion of homocysteine to cysteine and hence glutathione for proper immune system and detox functions.
Vitamin B6 is known to benefit immune function and cognitive function (depression, anxiety, autism, ADHD, and more).
SYMPTOMS OF DEFICIENCY
I would recommend that one consider this nutrient for any neurological (seizures, impaired brain function, irritability and confusion, autism, ADHD, etc.) or psychiatric (anxiety, depression, depersonalization etc.) condition. There were reports of seizures in infants who were fed formula that was without this nutrient in the 1950’s. Alcoholics with poor nutrition are at risk for this deficiency. Because of the importance in the methylation cycle and the reaction from taking homocysteine to cysteine and thus glutathione, deficiency could lead to:
– Cardiovascular (heart attacks, atherosclerosis, and strokes)
– Impaired brain function
– Decreased immune system (B6 needed for lymphocyte production and interleukin-2)
Chickpeas (1 cup) 1.1
Beef liver (3 oz) 0.9
Tuna (3 oz) 0.9
Potato w/skin 0.7
Fortified cereals 0.5
Other nuts (1oz) 0.1
SAFETY AND TOXICITY
This is a water-soluble B- vitamin which can only be toxic at high doses of vitamin supplements exceeding 500-1000 mg a day. Sensory neuropathy (pain or numbness in arms or legs and difficulty walking) have been reported.
TOLERABLE UPPER LIMITS
Teens and adults 100
If you are taking the following medications, be aware that they can interfere with B6 such that you should consider taking higher doses: isoniazid, cycloserine, penicillamine, and levodopa. High doses of vitamin B6 should be avoided if you are on phenobarbitol or phenytoin,. If you are taking tryptophan, you may need more vitamin B6.
Vitamin B6 may be taken as either pyridoxine HCl or P5P (pyridoxal-5-phosphate). The P5P form may be more effective, although some patients may benefit from taking both forms. Because vitamin B6 requires riboflavin, magnesium, and zinc in it’s metabolic pathways, it would be best that this is taken along with a multivitamin that has at least the RDA (recommended daily allowance) of these other nutrients.