Can an antioxidant megadose (not overdose, but any OTC "megadose" vitamin) incentive DNA disfavour?
This is one of those things that the famous Doctor Oz tossed off one day on TV, and not a soul slowed him down, as usual, and asked for citations or details. He said that is you have as much as 10,000 IU of Vitamin A in soon (which is 200% of your RDA), it will have the opposite of antioxidant effect, actually cause DNA damage.
I have searched extensively and cannot receive a breakthrough about this topic -- vitamin megadoses causing DNA damage -- using the standard internet turn upside down engines. Does anyone know the truth about megadoses of A? (I am not asking about simple vitamin A toxicity, by the way. I am aware of that.)
Thanks within advance for any help you can offer.
Answers:
This is an key and controversial issue in nutritional biochemistry.
It is controversial because there is some evidence that very giant doses of some micronutrients (vitamins and minerals) may have an oxidant effect and may damage DNA and other large molecules. However, most of these studies are "surrounded by vitro" and do NOT replicate "in vivo" conditions.
Any molecule (including H20 - water) in high satisfactory doses can be toxic to biological systems. Most micronutrients have a "U-shaped" biological response curve, which means inadequate doses (deficiency) can own negative effects, at adequate doses (which vary from party to person) there are "optimum" biological actions, and at excessive doses there are also refusal effects.
Chronically high doses of Vitamin A, Vitamin B6, Zinc, Selenium, etc. etc. do have potential to be cytotoxic - damaging to cellular molecules approaching DNA. However, many of these nutrients are far more likely to be inadequate contained by modern diets, and thus cause negative biological effects from their deficiency contained by cells! And, as the papers below suggest, this damage can be genomic damage - mar to DNA (from Deficiency).
Michael Fenech, in Australia, has done an extensive amount of research in this nouns. Below are links to Pubmed and some of his work. Start with the LAST paper, and work your way hindmost up the list from the bottom.
http://www.ncbi.nlm.nih.gov/pubmed/19155…
http://www.ncbi.nlm.nih.gov/pubmed/18762…
http://www.ncbi.nlm.nih.gov/pubmed/18412…
http://www.ncbi.nlm.nih.gov/pubmed/17693…
http://www.ncbi.nlm.nih.gov/pubmed/17684…
http://www.ncbi.nlm.nih.gov/pubmed/15956…
http://www.ncbi.nlm.nih.gov/pubmed/12067…
http://carcin.oxfordjournals.org/cgi/con…
Best wishes and good luck.
Here's a further:
http://www.ncbi.nlm.nih.gov/pubmed/19079…
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I have searched extensively and cannot receive a breakthrough about this topic -- vitamin megadoses causing DNA damage -- using the standard internet turn upside down engines. Does anyone know the truth about megadoses of A? (I am not asking about simple vitamin A toxicity, by the way. I am aware of that.)
Thanks within advance for any help you can offer.
Answers:
This is an key and controversial issue in nutritional biochemistry.
It is controversial because there is some evidence that very giant doses of some micronutrients (vitamins and minerals) may have an oxidant effect and may damage DNA and other large molecules. However, most of these studies are "surrounded by vitro" and do NOT replicate "in vivo" conditions.
Any molecule (including H20 - water) in high satisfactory doses can be toxic to biological systems. Most micronutrients have a "U-shaped" biological response curve, which means inadequate doses (deficiency) can own negative effects, at adequate doses (which vary from party to person) there are "optimum" biological actions, and at excessive doses there are also refusal effects.
Chronically high doses of Vitamin A, Vitamin B6, Zinc, Selenium, etc. etc. do have potential to be cytotoxic - damaging to cellular molecules approaching DNA. However, many of these nutrients are far more likely to be inadequate contained by modern diets, and thus cause negative biological effects from their deficiency contained by cells! And, as the papers below suggest, this damage can be genomic damage - mar to DNA (from Deficiency).
Michael Fenech, in Australia, has done an extensive amount of research in this nouns. Below are links to Pubmed and some of his work. Start with the LAST paper, and work your way hindmost up the list from the bottom.
http://www.ncbi.nlm.nih.gov/pubmed/19155…
http://www.ncbi.nlm.nih.gov/pubmed/18762…
http://www.ncbi.nlm.nih.gov/pubmed/18412…
http://www.ncbi.nlm.nih.gov/pubmed/17693…
http://www.ncbi.nlm.nih.gov/pubmed/17684…
http://www.ncbi.nlm.nih.gov/pubmed/15956…
http://www.ncbi.nlm.nih.gov/pubmed/12067…
http://carcin.oxfordjournals.org/cgi/con…
Best wishes and good luck.
Here's a further:
http://www.ncbi.nlm.nih.gov/pubmed/19079…
Related Questions: