[jefozabuss]

I've been taking "Opti-Men" from Optimum Nutrition for like 10 years now and it seems to have 50mg in a (full) serving that I take.

Since B6 is water soluble doesn't it mean most of it might just leave our body if not needed? (No storage in fat)

[richarlidad]

This is the mechanism of action:

Vitamin B6 is an antioxidant and coenzyme involved in amino acid, carbohydrate and lipid metabolism. Humans cannot directly produce active vitamin B6 (pyrixodal phosphate). However, salvage pathways allow the enzymatic conversion of vitamin B6 vitamers, including pyridoxine, pyridoxal and pyridoxamine by the enzyme pyridoxal kinase, into active vitamin B6.

In the body, active vitamin B6 is involved in metabolic reactions including GABA synthesis, monoamine neurotransmitter metabolism, the metabolism of polyunsaturated fatty acids and phospholipids, amino acid metabolism and the conversion of tryptophan to niacin.

Vitamin B6 reduces homocysteine levels by acting as a coenzyme for both cystathionine-beta-synthase (CBS) and cystathionine-gamma-lyase (CSE) in the transsulfuration pathway following a postprandial methionine-load (after a meal). In the fasting state, homocysteine is primarily metabolised via the remethylation pathway which does not require vitamin B6.

In the transsulfuration pathway, homocysteine is converted to cystathionine by CBS, then to cysteine by CSE. During moderate vitamin B6 deficiency, CSE exhibits much greater loss of activity compared to CBS. However cysteine production is preserved due to an accumulation of cellular and plasma cystathionine in a larger substrate pool which compensates for reduced CSE activity. As CBS is a vitamin B6-dependent enzyme, CBS deficiency (typically genetic causes) can result in elevated fasting and post-methionine load homocysteine due to impaired synthesis of cystathionine from homocysteine. Elevated homocysteine levels increase oxidative stress, may inhibit nitric oxide synthesis, increase vascular endothelial cell damage and accelerate low-density lipoprotein (LDL) deposition in arteries.

Vitamin B6 may significantly decrease the rate of formation of kidney stones in patients with type I primary hyperoxaluria, a condition caused by a deficiency of the liver-specific enzyme alanine-glyoxylate:aminotransferase by reducing levels of urinary oxalate. The protective effect of vitamin B6 supplementation for kidney stones appears to only occur in women (-34% risk) and not men.

[mdavid626]

Can you boil this down for us? Does or does not B6 accumulate in the body?

[mdavid626]

I agree, as B6 is water soluble, it should be fine to take more, the body just gets rid of it.