Giraffe
Member
- Joined
- Jun 20, 2015
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- 3,730
I googled German speaking websites to find out what is considered "normal" over here. This Swiss website here, was the first one to pop up, and their normal value for vitamin B6 is 20-90 ng/mL. This value is a lot higher than the one stated by your lab and much closer to your value.
I think that the "normal value" is nothing but a statistical figure. I guess they test what they call a representative population, and get a huge range of values. Then they exclude the highest and lowest 2.5%. The result is a range in which 95% of the population fits into.
@gilson dantas , I don't know, maybe your high value merely means that you are among the best nourished individuals the labs have ever seen. :) If I come across something regarding high vitamin B6 levels I'll post it here.
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B Vitamins and the Brain: Mechanisms, Dose and Efficacy—A Review
Among other topics, the author discusses what he calls the "homocysteine hypothesis" and its lack to acknowledge the role of other vitamins than B6, B9 and B12. He also discusses some shortcomings of RDA.
I think that the "normal value" is nothing but a statistical figure. I guess they test what they call a representative population, and get a huge range of values. Then they exclude the highest and lowest 2.5%. The result is a range in which 95% of the population fits into.
@gilson dantas , I don't know, maybe your high value merely means that you are among the best nourished individuals the labs have ever seen. :) If I come across something regarding high vitamin B6 levels I'll post it here.
.....
B Vitamins and the Brain: Mechanisms, Dose and Efficacy—A Review
Among other topics, the author discusses what he calls the "homocysteine hypothesis" and its lack to acknowledge the role of other vitamins than B6, B9 and B12. He also discusses some shortcomings of RDA.
The final B vitamin with an ascribed upper limit is vitamin B6 which has an upper limit set at 100 mg/day (approximately 75 × RDA) in the US on the basis of case reports of reversible sensory neuropathy following doses in excess of 1000 mg taken for extended periods. However, it is notable that multiple clinical trials entailing consuming up to 750 mg/day of vitamin B6 for a number of years have demonstrated a lack of neuropathic side effects [15].
In population studies, intakes of vitamin B6 well in excess of the RDA, along with associated biochemical levels of pyridoxal-5′-phosphate, have also been found to be inversely related to a range of inflammatory biomarkers, with those individuals exhibiting higher levels of inflammatory biomarkers requiring several times the RDA of vitamin B6 merely to avoid deficiency [53,54].
However, it contrasted with re-analysis of the data from two studies [67] that found that whereas low vitamin B12 was associated with cognitive impairment and dementia, and low vitamin B6 was associated with cognitive impairment, there was no relationship between brain function and folate, homocysteine or the MTHFR C677TT polymorphism. .
It is also notable that treatments containing all of the B vitamins will inevitably reduce homocysteine (see [159,165]), and indeed, given the direct contribution of both niacin and riboflavin to the folate/methionine cycles, they should theoretically be more effective than small sub-groups of B vitamins in this regard. It is therefore difficult to conceive of any potential downsides to undertaking research with the full range of B vitamins. Of course, the luxury of being able to attribute any benefits to a single molecule and/or a single mechanism will be lost, but given the equivocal nature of the large body of evidence to date with regards to the homocysteine hypothesis, this loss would appear supportable, if not inevitable.