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High dose nutritional supplements and cancer risk
Category: Cancer ? Food ? Quackery and fraud
Posted on: May 5, 2010 6:41 AM, by revere
Regular readers know I don't have strong feelings about nutritional supplements and herbal medicine, unlike some of my medical blogger colleagues. I don't recommend or use them but for the most part it's not a subject that really gets me going, probably because I don't know enough about abuses. A lot of regular medical practice is not that soundly based, either, and some of it is pretty harmful. That's also not a subject that gets me going.
The one prejudice I do have I got from my physician and surgeon father. His diet advice was "everything in moderation." That goes for nutritional supplements as well and I consider it as wise now as it was 60 years ago when he gave it to his patients. Since we all look for items that reinforce our prejudices, here's one I found that works for me:
Cells grown in a petri dish need much higher oxygen levels (about 20%) than present in normal tissue (3 - 5%). But the technique of growing the cardiac stem cells is technically difficult and many cells are rejected because they have genetic abnormalities, presumably from the higher oxygen tension. So he tried adding anti-oxidants like vitamins E and C. That's when he accidentally discovered these compounds were causing genetic abnormalities that might later lead to cancer.
This doesn't mean that super doses of nutritional supplements cause cancer. There is a long way between this finding and that conclusion. But it doesn't rule it out either and it is a red flag, even if a small one.
And for me it reinforces one of my prejudices: everything in moderation. Including nutritional supplements.
Category: Cancer ? Food ? Quackery and fraud
Posted on: May 5, 2010 6:41 AM, by revere
Regular readers know I don't have strong feelings about nutritional supplements and herbal medicine, unlike some of my medical blogger colleagues. I don't recommend or use them but for the most part it's not a subject that really gets me going, probably because I don't know enough about abuses. A lot of regular medical practice is not that soundly based, either, and some of it is pretty harmful. That's also not a subject that gets me going.
The one prejudice I do have I got from my physician and surgeon father. His diet advice was "everything in moderation." That goes for nutritional supplements as well and I consider it as wise now as it was 60 years ago when he gave it to his patients. Since we all look for items that reinforce our prejudices, here's one I found that works for me:
High doses of antioxidant nutritional supplements, such as vitamins C and E, can increase genetic abnormalities in cells, which may predispose supplement-takers to developing cancer, according to a new study from the Cedars-Sinai Heart Institute. The study, led by Eduardo Marb?n, M.D., Ph.D., director of the Cedars-Sinai Heart Institute, was published online today in the medical journal Stem Cells. The study also will appear in the journal's July printed edition.
Marb?n and his team accidentally discovered the danger of excessive antioxidant doses while seeking a way to reduce the genetic abnormalities that occurred naturally when the scientists sought to multiply human cardiac stem cells.
Marb?n stressed that the study's finding applies only to excessive nutritional supplements and not to foods that are rich in antioxidants, such as milk, oranges, blueberries and peanuts. In recent years, multiple studies have touted the benefits of foods rich in antioxidants.
"Taking one multivitamin daily is fine, but a lot of people take way too much because they think if a little is good, a lot must be better," said Marb?n, who is also the Mark Siegel Family Professor at Cedars-Sinai. "That is just not the case. If you are taking 10 or 100 times the amount in a daily multivitamin, you may be predisposing your cells to developing cancer, therefore doing yourself more harm than good." (Cedar Sinai press release via Science Blog [not related to scienceblogs.com])
Marb?n is not an anti-supplement crusader (nor am I), so how he discovered this is interesting. He is working on ways to regenerate heart muscle damaged by a heart attack. He removes a bit of heart tissue from the patient and he uses it to grow cardiac stem cells in tissue culture. He then reinjects the stem cells into regions of the damaged heart so that healthy heart tissue can be regenerated. He has actually tried this in a patient and is awaiting results early next year.Marb?n and his team accidentally discovered the danger of excessive antioxidant doses while seeking a way to reduce the genetic abnormalities that occurred naturally when the scientists sought to multiply human cardiac stem cells.
Marb?n stressed that the study's finding applies only to excessive nutritional supplements and not to foods that are rich in antioxidants, such as milk, oranges, blueberries and peanuts. In recent years, multiple studies have touted the benefits of foods rich in antioxidants.
"Taking one multivitamin daily is fine, but a lot of people take way too much because they think if a little is good, a lot must be better," said Marb?n, who is also the Mark Siegel Family Professor at Cedars-Sinai. "That is just not the case. If you are taking 10 or 100 times the amount in a daily multivitamin, you may be predisposing your cells to developing cancer, therefore doing yourself more harm than good." (Cedar Sinai press release via Science Blog [not related to scienceblogs.com])
Cells grown in a petri dish need much higher oxygen levels (about 20%) than present in normal tissue (3 - 5%). But the technique of growing the cardiac stem cells is technically difficult and many cells are rejected because they have genetic abnormalities, presumably from the higher oxygen tension. So he tried adding anti-oxidants like vitamins E and C. That's when he accidentally discovered these compounds were causing genetic abnormalities that might later lead to cancer.
This doesn't mean that super doses of nutritional supplements cause cancer. There is a long way between this finding and that conclusion. But it doesn't rule it out either and it is a red flag, even if a small one.
And for me it reinforces one of my prejudices: everything in moderation. Including nutritional supplements.