Demi
Tue, Apr-01-08, 03:40
Have just received the following interesting article in an email newsletter from British nutritionist, Patrick Holford.
Vitamin Killers
THE VITAMIN CANCER KILLERS
A couple of times a year surveys hit the headlines, or TV or radio programmes such as The Rise of the Lifestyle Nutritionists (click here (http://www.patrickholford.com/content.asp?id_Content=2273) for Patrick's response to this) on Radio Four are broadcast, claiming that supplements do no good at all, and may even harm.
Of course, few journalists have the time to study the proper evidence - but if they did they would find that the actual results can be startlingly different to what appears in the press release.
A classic example was a recent survey published in the American Journal of Respiratory and Critical Care Medicine. [1] "Supplemental multivitamins, vitamin C, vitamin E and folate were not associated with a deceased risk of lung cancer. Supplemental vitamin E was associated with a small increased risk" - said the summary. "We found no evidence of a lower incidence of lung cancer," declare the authors.
Well, that's strange because it's not what their figures show. Let's use this study to show how false vitamin scare headlines are created.
First, the vital statistics: this was a study of over 77,000 elderly people, from which there were 521 cases of lung cancer. This is quite a small number to do statistics on. The question was, did supplements increase or decrease the risk of cancer?
You'll not be surprised to find that the biggest risk factor was smoking, increasing risk by 28 times. But what about supplements? Among smokers, those who took multivitamins more often (ie daily), or took the most vitamin C (above 322mg), or the most folic acid (above 400mcg) had a small, but non-significant, decrease in risk.
The general trend in several other studies (for example, click here (http://www.patrickholford.com/content.asp?id_Content=2168) to access the Gladys Block study) seems to show that those who take the most supplements combined, in higher doses, have the lowest risk of disease.
Dose of vitamin E appears to be key factor
Surprisingly, given the scare headlines this study spawned in the newspapers, the single biggest change in risk in relation to supplements, was a 20% reduction in risk in those smokers who took 42mg up to 200mg of vitamin E. This was close to significance. Yet this positive result wasn't even referred to, not even once. It was simply ignored.
However, those who took more than 215mg of vitamin E had an equivalent 19% increased risk, which was not statistically significant. Yet that is what hit the headlines! Talk about bias.
But why would a higher dose of vitamin E increase risk and a low dose decrease risk - a finding that has also been reported in those with cardiovascular disease? Vitamin E, under certain circumstances can act as a pro-oxidant, not an anti-oxidant. One such circumstance would be if a person was taking cholesterol-lowering medication, since statins block another important antioxidant called co-enzyme Q10. CoQ10 works to recycle vitamin E - after it's disarmed a harmful oxidant, vitamin E becomes an oxidant itself - so CoQ10 turns it back into an antioxidant. But without sufficient CoQ10, it stays as an oxidant - causing damage itself.
In this study, it is highly likely that these elderly smokers were taking statins, but that factor isn't considered. Coupled with a high level of oxidants from smoking, the increased risk of lung cancer is quite frankly to be expected.
Antioxidants are team players
You can't just give one antioxidant and expect miracles. Many studies have reported decreased risk when a combination of antioxidants, especially in high doses, are given. So did those people taking all these supplements together have a lower risk? In this study, the combinationof supplements was suspiciously not analysed, although it would have been easy to do.
So what can we conclude? Well, the journal's editorial concludes that fruit and veg are heroes and supplements villains. That's strange because this study actually found that those with the highest intake of fruit and vegetables (five or more servings a day) had half the reduction in risk (10%), compared to those supplementing 42 to 200mg of vitamin E (20%) - which, by the way, is three to ten times more than what most people eat. So, a more accurate conclusion would be that the villain, vitamin E, in moderate doses is twice as effective as eating five servings of fruit and veg!
The truthful deduction from this rather weak study is that if you smoke and supplement very large amounts of vitamin E, you might fractionally increase your risk of lung cancer. However, if you supplement up to 200mg, you might fractionally decrease your risk. But what really makes a difference is to stop smoking!
It reminds me ofthe often-quoted study that found a non-significant increased risk of lung cancer in smokers who took beta-carotene on its own. But then there's another study, involving 13,000 people between the ages of 35 and 60, which investigated the effects of a pill containing a cocktail of antioxidants (beta-carotene, vitamin C and E). This found a highly significant 31% reduction in the risk of all cancers in men, plus an overall 37% lower death rate.
A further study found this combination of antioxidants highly protective against colon cancer, but there was no such beneficial effect among those who were heavy drinkers and smokers and only took beta-carotene. But you try finding a heavy drinker and smoker who pops beta-carotene or vitamin E on its own! Talk about a needle in a haystack.
Twisting the evidence
The most widely quoted, and controversial, meta-analysis was that of Bjelakovic, published last year in the Journal of the American Medical Association. [2] This was a study o studies which looked at all-cause mortality in association with supplementation of the antioxidants vitamin A, beta-carotene, vitamin E and vitamin C. The summary of this study says: "treatment with beta carotene, vitamin A, and vitamin E may increase mortality", creating the impression these anti-oxidants are no good.
What it failed to say in the summary, all of which are clearly stated in the results, is that "vitamin C, given singly or in combination with other antioxidants, did not affect mortality, and selenium, given singly or in combination with other antioxidant supplements, may reduce mortality". The summary also fails to say that "beta-carotene or vitamin A did not show increase in mortality if given in combination with other antioxidants', or that "vitamin E, given singly or combined with four other antioxidants, did not significantly influence mortality".
The main reason this meta-analysis is so controversial is that the one study, by a Dr Correa from the pathology department at te Louisiana State University Health Sciences Centre, that apparently skewed results for antioxidants overall towards a negative, showed a clear protective effective of antioxidant supplements against gastrointestinal cancer. [3]
I decided to contact Dr Correa and he was "amazed", he said, because his research, "far from being negative, had shown clear benefit from taking vitamins". Correa told us there was no way the study could show anything about mortality. "Our study was designed for evaluation of the progress of pre-cancerous lesions," he said. "It did not intend, and did not have the power, to study mortality and has no value to examine mortality of cancer." It reminds me of that saying 'there's lies, damned lies and statistics'.
What I find most extraordinary is that these studies all appear in 'peer-reviewed' journals, meaning that a panel of experts examine the results before publication. It's really not hard to pick up these kind of discrepancies if you just read the papers. It remindsme of the story when, in the restroom during a medical conference, Dr John Hoffer (son of Dr Abram Hoffer, the man who discovered niacin's amazing effects on both schizophrenia and reducing cholesterol) said to twice-Nobel-prize-winning Linus Pauling, "Will anyone ever listen to us until we have studies published in peer-reviewed journals?" Linus looked down, then looked at him and said, "Son, we are all peers".
Take-home message
So, what's the take home message of this latest study? My advice would be not to supplement beta-carotene or high dose (above 200mg) of vitamin E on their own if you are a heavy smoker or drinker - and to stop smoking and excessive drinking!
But even among smokers, a high dietary intake of beta-carotene is not associated with increased risk. So, keep eating the carrots and supplementing all-round antioxidant supplements or multivitamins, as many other studies show that this combination results in a clear reduction of cancer risk.
I personally recommend anyone over 50, which now includes me, to take additional antioxidants in the right combination supplement. That means vitamin E (100-200mg), co-enzyme Q10, vitamin C, beta-carotene, lipoic acid, selenium, glutathione or N-acetyl cysteine, plus resveratrol. I have yet to find one single study that shows anything but benefit from this kind of combination, which respects the fact that antioxidants are team players. Even if this latest study doesn't confirm the benefit, I also recommend eating lots of fruit and veg.
You can play a part in helping to get a more balanced view of nutrition and supplementation in the media. If you listened to the BBC Radio 4 programme The Rise of the Lifestyle Nutritionists and felt it was biased then you can complain to the BBC simply by clicking here (http://www.bbc.co.uk/complaints/).
References
1. C Slatore et al, 'Long-term use of supplemental multivitamins, viamin C, vitamin E, and folate does not reduce the risk of lung cancer', American Journal of Respiratory and Critical Care Medicine (2008), vol 177, pp524-530.
2. G Bjelakovic et al, 'Mortality in randomized trials of antioxidant supplements for primary and secondary prevention', Journal of the American Medical Association (2007), vol 297, pp842-857 .
3. P Correa et al, 'Chemoprevention of gastric dysplasia: Randomized trial of antioxidant supplements and anti-Helicobacter pylori therapy', Journal of the National Cancer Institute (2000), vol 92, pp1881-8.
Vitamin Killers
THE VITAMIN CANCER KILLERS
A couple of times a year surveys hit the headlines, or TV or radio programmes such as The Rise of the Lifestyle Nutritionists (click here (http://www.patrickholford.com/content.asp?id_Content=2273) for Patrick's response to this) on Radio Four are broadcast, claiming that supplements do no good at all, and may even harm.
Of course, few journalists have the time to study the proper evidence - but if they did they would find that the actual results can be startlingly different to what appears in the press release.
A classic example was a recent survey published in the American Journal of Respiratory and Critical Care Medicine. [1] "Supplemental multivitamins, vitamin C, vitamin E and folate were not associated with a deceased risk of lung cancer. Supplemental vitamin E was associated with a small increased risk" - said the summary. "We found no evidence of a lower incidence of lung cancer," declare the authors.
Well, that's strange because it's not what their figures show. Let's use this study to show how false vitamin scare headlines are created.
First, the vital statistics: this was a study of over 77,000 elderly people, from which there were 521 cases of lung cancer. This is quite a small number to do statistics on. The question was, did supplements increase or decrease the risk of cancer?
You'll not be surprised to find that the biggest risk factor was smoking, increasing risk by 28 times. But what about supplements? Among smokers, those who took multivitamins more often (ie daily), or took the most vitamin C (above 322mg), or the most folic acid (above 400mcg) had a small, but non-significant, decrease in risk.
The general trend in several other studies (for example, click here (http://www.patrickholford.com/content.asp?id_Content=2168) to access the Gladys Block study) seems to show that those who take the most supplements combined, in higher doses, have the lowest risk of disease.
Dose of vitamin E appears to be key factor
Surprisingly, given the scare headlines this study spawned in the newspapers, the single biggest change in risk in relation to supplements, was a 20% reduction in risk in those smokers who took 42mg up to 200mg of vitamin E. This was close to significance. Yet this positive result wasn't even referred to, not even once. It was simply ignored.
However, those who took more than 215mg of vitamin E had an equivalent 19% increased risk, which was not statistically significant. Yet that is what hit the headlines! Talk about bias.
But why would a higher dose of vitamin E increase risk and a low dose decrease risk - a finding that has also been reported in those with cardiovascular disease? Vitamin E, under certain circumstances can act as a pro-oxidant, not an anti-oxidant. One such circumstance would be if a person was taking cholesterol-lowering medication, since statins block another important antioxidant called co-enzyme Q10. CoQ10 works to recycle vitamin E - after it's disarmed a harmful oxidant, vitamin E becomes an oxidant itself - so CoQ10 turns it back into an antioxidant. But without sufficient CoQ10, it stays as an oxidant - causing damage itself.
In this study, it is highly likely that these elderly smokers were taking statins, but that factor isn't considered. Coupled with a high level of oxidants from smoking, the increased risk of lung cancer is quite frankly to be expected.
Antioxidants are team players
You can't just give one antioxidant and expect miracles. Many studies have reported decreased risk when a combination of antioxidants, especially in high doses, are given. So did those people taking all these supplements together have a lower risk? In this study, the combinationof supplements was suspiciously not analysed, although it would have been easy to do.
So what can we conclude? Well, the journal's editorial concludes that fruit and veg are heroes and supplements villains. That's strange because this study actually found that those with the highest intake of fruit and vegetables (five or more servings a day) had half the reduction in risk (10%), compared to those supplementing 42 to 200mg of vitamin E (20%) - which, by the way, is three to ten times more than what most people eat. So, a more accurate conclusion would be that the villain, vitamin E, in moderate doses is twice as effective as eating five servings of fruit and veg!
The truthful deduction from this rather weak study is that if you smoke and supplement very large amounts of vitamin E, you might fractionally increase your risk of lung cancer. However, if you supplement up to 200mg, you might fractionally decrease your risk. But what really makes a difference is to stop smoking!
It reminds me ofthe often-quoted study that found a non-significant increased risk of lung cancer in smokers who took beta-carotene on its own. But then there's another study, involving 13,000 people between the ages of 35 and 60, which investigated the effects of a pill containing a cocktail of antioxidants (beta-carotene, vitamin C and E). This found a highly significant 31% reduction in the risk of all cancers in men, plus an overall 37% lower death rate.
A further study found this combination of antioxidants highly protective against colon cancer, but there was no such beneficial effect among those who were heavy drinkers and smokers and only took beta-carotene. But you try finding a heavy drinker and smoker who pops beta-carotene or vitamin E on its own! Talk about a needle in a haystack.
Twisting the evidence
The most widely quoted, and controversial, meta-analysis was that of Bjelakovic, published last year in the Journal of the American Medical Association. [2] This was a study o studies which looked at all-cause mortality in association with supplementation of the antioxidants vitamin A, beta-carotene, vitamin E and vitamin C. The summary of this study says: "treatment with beta carotene, vitamin A, and vitamin E may increase mortality", creating the impression these anti-oxidants are no good.
What it failed to say in the summary, all of which are clearly stated in the results, is that "vitamin C, given singly or in combination with other antioxidants, did not affect mortality, and selenium, given singly or in combination with other antioxidant supplements, may reduce mortality". The summary also fails to say that "beta-carotene or vitamin A did not show increase in mortality if given in combination with other antioxidants', or that "vitamin E, given singly or combined with four other antioxidants, did not significantly influence mortality".
The main reason this meta-analysis is so controversial is that the one study, by a Dr Correa from the pathology department at te Louisiana State University Health Sciences Centre, that apparently skewed results for antioxidants overall towards a negative, showed a clear protective effective of antioxidant supplements against gastrointestinal cancer. [3]
I decided to contact Dr Correa and he was "amazed", he said, because his research, "far from being negative, had shown clear benefit from taking vitamins". Correa told us there was no way the study could show anything about mortality. "Our study was designed for evaluation of the progress of pre-cancerous lesions," he said. "It did not intend, and did not have the power, to study mortality and has no value to examine mortality of cancer." It reminds me of that saying 'there's lies, damned lies and statistics'.
What I find most extraordinary is that these studies all appear in 'peer-reviewed' journals, meaning that a panel of experts examine the results before publication. It's really not hard to pick up these kind of discrepancies if you just read the papers. It remindsme of the story when, in the restroom during a medical conference, Dr John Hoffer (son of Dr Abram Hoffer, the man who discovered niacin's amazing effects on both schizophrenia and reducing cholesterol) said to twice-Nobel-prize-winning Linus Pauling, "Will anyone ever listen to us until we have studies published in peer-reviewed journals?" Linus looked down, then looked at him and said, "Son, we are all peers".
Take-home message
So, what's the take home message of this latest study? My advice would be not to supplement beta-carotene or high dose (above 200mg) of vitamin E on their own if you are a heavy smoker or drinker - and to stop smoking and excessive drinking!
But even among smokers, a high dietary intake of beta-carotene is not associated with increased risk. So, keep eating the carrots and supplementing all-round antioxidant supplements or multivitamins, as many other studies show that this combination results in a clear reduction of cancer risk.
I personally recommend anyone over 50, which now includes me, to take additional antioxidants in the right combination supplement. That means vitamin E (100-200mg), co-enzyme Q10, vitamin C, beta-carotene, lipoic acid, selenium, glutathione or N-acetyl cysteine, plus resveratrol. I have yet to find one single study that shows anything but benefit from this kind of combination, which respects the fact that antioxidants are team players. Even if this latest study doesn't confirm the benefit, I also recommend eating lots of fruit and veg.
You can play a part in helping to get a more balanced view of nutrition and supplementation in the media. If you listened to the BBC Radio 4 programme The Rise of the Lifestyle Nutritionists and felt it was biased then you can complain to the BBC simply by clicking here (http://www.bbc.co.uk/complaints/).
References
1. C Slatore et al, 'Long-term use of supplemental multivitamins, viamin C, vitamin E, and folate does not reduce the risk of lung cancer', American Journal of Respiratory and Critical Care Medicine (2008), vol 177, pp524-530.
2. G Bjelakovic et al, 'Mortality in randomized trials of antioxidant supplements for primary and secondary prevention', Journal of the American Medical Association (2007), vol 297, pp842-857 .
3. P Correa et al, 'Chemoprevention of gastric dysplasia: Randomized trial of antioxidant supplements and anti-Helicobacter pylori therapy', Journal of the National Cancer Institute (2000), vol 92, pp1881-8.