Nutrition Industry Executive: First Word—Get Back To Work! [May 08]

First Word—Get Back To Work! © NIE

As this issue of Nutrition Industry Executive goes to press, a “new report” from a group of international scientists has been receiving a lot of attention in the media, primarily due to the study’s conclusion that “there is no evidence to support antioxidant supplements for…prevention of mortality.” Or, as one news source interpreted the study, “Vitamins A, C and E are a waste of time.” Worse yet, the study also found that “vitamin A, beta-carotene and vitamin E may in fact increase mortality.” Well, I guess that’s it then. The dietary supplement industry can just close up shop now, because a group of Danish scientists says there is no evidence supporting the health benefits of antioxidant supplements—including best-sellers like C and E—and, in fact, these products might actually be causing harm and lowering life expectancies. The new study (actually an updated meta-analysis, or “study of studies”) was published in The Cochrane Database of Systematic Reviews by scientists affiliated with Copenhagen University. The researchers based their conclusions on an analysis of 67 separate studies related to antioxidant supplements. If the report’s conclusions sound familiar to you, that’s because the authors are the same ones who published similar (and heavily criticized) meta-analyses previously in the Journal of the American Medical Association (Feb. 2007) and the Lancet (Sept. 2004). But before we issue a blanket apology to the world for providing vitamin C pills, let’s look a little deeper at the new study and see if its conclusions are perhaps slightly in doubt and/or biased. First, as pointed out by the Council for Responsible Nutrition (CRN), “An extensive body of scientific research has shown that taking antioxidant supplements, including vitamins C and E, beta-carotene, zinc and selenium, consistently over long-terms can play a role in reducing the risk of chronic disease.” In fact, noted CRN, the Danish researchers themselves identified nearly 750 clinical trials on antioxidant supplements that could have been included in their meta-analysis; however, the authors chose to exclude all but 67 of these studies from their review (less than nine percent of the published research). Why limit to such a small pool of the available research? The study “appears to be a systematic attempt by the authors to publish work that supports their own pre-determined conclusions about antioxidants and the way they should be regulated,” CRN charged. Backing up this charge, CRN noted that: • In selecting which randomized clinical trials (RCTs) to use, the researchers excluded any RCT in which no deaths were reported (405 articles), “which begs the question of how one can properly evaluate whether a substance can prevent mortality when studies that demonstrate no harm are automatically excluded,” CRN pointed out. • The selected studies used in the meta-analysis included studies examining different antioxidants, different doses, different populations with different health statuses, for different durations—in short, the authors combined heterogeneous studies and tried to make one generalized conclusion. “As the saying goes, it’s like comparing apples to oranges,” said CRN. • The authors relied on their own self-selected and far-from-agreed-upon criteria for assessing bias where they established specific inclusion criteria. If any of the inclusion criteria from a scientific trial was deemed “inadequate” in the researchers’ opinions, then the study was deemed “high-risk bias” and not included. “Not surprisingly, the studies that are considered high-risk bias in this meta-analysis tend to be those that show a benefit to antioxidant supplementation, while those labeled as low-risk bias tended to show harm,” CRN commented. • Only “all-cause mortality” was assessed in the review. As a result, the authors didn’t seek to eliminate deaths that may have been caused by accident, homicide, suicide or medical conditions that have nothing to do with supplementation. • The vitamin A RCTs that were included used extremely high doses of vitamin A, in some cases well above the Tolerable Upper Limit established by the Dietary Reference Intakes, which “may have significantly skewed the overall results of this analysis,” CRN said. John Hathcock, PhD, senior vice president of scientific and international affairs for CRN, summarized this newest meta-analysis: “The conclusions one can reach from this are very limited. In fact, a variation of these results has already been published and was heavily criticized, due in part to the authors’ systematic exclusion of studies that didn’t support the hypothesis they were trying to prove. With nearly 750 studies to choose from, it’s interesting that they chose to include only 67. It is their exclusions, not the inclusions, where the fault lies.” Added Andrew Shao, PhD, vice president of scientific and regulatory affairs at CRN, “Antioxidant supplements are certainly not meant to be magic bullets and should not realistically be expected to undo a lifetime of unhealthy habits. However, when used properly, in combination with eating a healthy diet, getting plenty of exercise, not smoking, etc., antioxidant supplements can play an important role in promoting overall health.” Look for more about this developing story in the next issue of NIE, but for now, I guess it’s okay for us all to go back to work. Daniel McSweeney Publisher/Editorial Director

First Word—Get Back To Work! © NIE

As this issue of Nutrition Industry Executive goes to press, a “new report” from a group of international scientists has been receiving a lot of attention in the media, primarily due to the study’s conclusion that “there is no evidence to support antioxidant supplements for…prevention of mortality.” Or, as one news source interpreted the study, “Vitamins A, C and E are a waste of time.”

Worse yet, the study also found that “vitamin A, beta-carotene and vitamin E may in fact increase mortality.”

Well, I guess that’s it then. The dietary supplement industry can just close up shop now, because a group of Danish scientists says there is no evidence supporting the health benefits of antioxidant supplements—including best-sellers like C and E—and, in fact, these products might actually be causing harm and lowering life expectancies.

The new study (actually an updated meta-analysis, or “study of studies”) was published in The Cochrane Database of Systematic Reviews by scientists affiliated with Copenhagen University. The researchers based their conclusions on an analysis of 67 separate studies related to antioxidant supplements.
If the report’s conclusions sound familiar to you, that’s because the authors are the same ones who published similar (and heavily criticized) meta-analyses previously in the Journal of the American Medical Association (Feb. 2007) and the Lancet (Sept. 2004).

But before we issue a blanket apology to the world for providing vitamin C pills, let’s look a little deeper at the new study and see if its conclusions are perhaps slightly in doubt and/or biased.

First, as pointed out by the Council for Responsible Nutrition (CRN), “An extensive body of scientific research has shown that taking antioxidant supplements, including vitamins C and E, beta-carotene, zinc and selenium, consistently over long-terms can play a role in reducing the risk of chronic disease.”
In fact, noted CRN, the Danish researchers themselves identified nearly 750 clinical trials on antioxidant supplements that could have been included in their meta-analysis; however, the authors chose to exclude all but 67 of these studies from their review (less than nine percent of the published research).

Why limit to such a small pool of the available research? The study “appears to be a systematic attempt by the authors to publish work that supports their own pre-determined conclusions about antioxidants and the way they should be regulated,” CRN charged.

Backing up this charge, CRN noted that:
• In selecting which randomized clinical trials (RCTs) to use, the researchers excluded any RCT in which no deaths were reported (405 articles), “which begs the question of how one can properly evaluate whether a substance can prevent mortality when studies that demonstrate no harm are automatically excluded,” CRN pointed out.
• The selected studies used in the meta-analysis included studies examining different antioxidants, different doses, different populations with different health statuses, for different durations—in short, the authors combined heterogeneous studies and tried to make one generalized conclusion. “As the saying goes, it’s like comparing apples to oranges,” said CRN.
• The authors relied on their own self-selected and far-from-agreed-upon criteria for assessing bias where they established specific inclusion criteria. If any of the inclusion criteria from a scientific trial was deemed “inadequate” in the researchers’ opinions, then the study was deemed “high-risk bias” and not included. “Not surprisingly, the studies that are considered high-risk bias in this meta-analysis tend to be those that show a benefit to antioxidant supplementation, while those labeled as low-risk bias tended to show harm,” CRN commented.
• Only “all-cause mortality” was assessed in the review. As a result, the authors didn’t seek to eliminate deaths that may have been caused by accident, homicide, suicide or medical conditions that have nothing to do with supplementation.
• The vitamin A RCTs that were included used extremely high doses of vitamin A, in some cases well above the Tolerable Upper Limit established by the Dietary Reference Intakes, which “may have significantly skewed the overall results of this analysis,” CRN said.

John Hathcock, PhD, senior vice president of scientific and international affairs for CRN, summarized this newest meta-analysis: “The conclusions one can reach from this are very limited. In fact, a variation of these results has already been published and was heavily criticized, due in part to the authors’ systematic exclusion of studies that didn’t support the hypothesis they were trying to prove. With nearly 750 studies to choose from, it’s interesting that they chose to include only 67. It is their exclusions, not the inclusions, where the fault lies.”

Added Andrew Shao, PhD, vice president of scientific and regulatory affairs at CRN, “Antioxidant supplements are certainly not meant to be magic bullets and should not realistically be expected to undo a lifetime of unhealthy habits. However, when used properly, in combination with eating a healthy diet, getting plenty of exercise, not smoking, etc., antioxidant supplements can play an important role in promoting overall health.”

Look for more about this developing story in the next issue of NIE, but for now, I guess it’s okay for us all to go back to work.

Daniel McSweeney
Publisher/Editorial Director