Friday, April 21, 2006
How Nutrition Research Fumbles
Life Extension Foundation published an aticle in their 2006 Collector's Edition about Vitamin E. They discussed a review article, published in JAMA on August 11, 2004, that "extolled the benefits of gamma tocopherol". I don't have access to this review article, but the basic message in LEF's article is that JAMA validated what LEF has been saying for 8 years. All the studies with negative results for Vitamin E have been testing the wrong form. Alpha tocopherol, especially the artificial form, is not beneficial in large amounts by itself. The gamma form is the better antioxidant. Minimally, you should be taking a mixed form - one that resembles the mix you would find in nuts.
Assuming this is true (still an assumption since the research is not conclusive) this is one illustration of how medical science fumbles. Not that LEF is beyond criticism either - more on that at the end of this post.
Vitamin E research began the way that a lot of medical science begins. Population studies are mined for difference in outcomes. Some examples are the famous "seven countries" study about cholesterol and CHD, the big longitudinal nurses studies - NHANES - for the effects of antioxidants like beta carotene and E, and the lower incidence of CHD in pre-menopausal women.
From this data, a hypothesis is formulated. In all these cases substance "a" prevents disease "b". Because good science - science that will be funded by a review committee and pass muster for publication - prefers double-blind studies that test single substances, these hypotheses often focus on single substances. The bias for single substances also relatest to the drug approval process in the FDA - and patent law. So, a medical researcher will decide to study - and will often announce the finding based on the population studies - whether "a" prevents "b". They will embark on a long series of these studies. Drug companies and food manufacturers will rush to develop products and exploit this. Press interviews and advertising will reinforce this.
Unfortunately, many times it's been found that the single substance doesn't do the advertised job. The hypothesis is apparenly false and the evidence just doesn't hold up.
So, what goes wrong? Perhaps their is no causal relationship - just a correlative one. Maybe the single substance is not responsible for the effect alone. It's part of a complex that is required to have the effect. Sometimes, more is not better. There is a dose dependency - a range of efficacy. Perhaps the testing was often the wrong amounts. And then, the body is a very complex thing, with lots of redundancy and feedback loops.
What harm is done when these hypotheses are interpreted as fact too early? Sometimes, real harm is done when doctors act on the early results, pushed by drug companies eager for profits. HRT is an example. High alpha tocopherol doses increased the incidence of stroke. High beta carotene intake increase lung cancers in smokers.
But another serious casualty is public confidence in science. It makes science look flaky and unreliable. It reinforces the notion that all problems can be cured with a "magic pill". More careful study is needed before acting on these hypotheses.
Why do we do this? Money is one reason. Drug and food companies make money from this. And researchers get funded for these overly simplistic, but conventionally framed hypotheses. And, as Nisbett explains in The Geography of Thought, Westerners prefer the single substance approach to a more Eastern wholistic approach. We tend to ignore the background, the context, the environment. We look for a main character, a hero.
It's this last problem that is the most troubling. If we are always trying to advance medical science by understanding the effects of single substances on health, we may never really understand the system.
So, what's the criticism of LEF? They are all about single substances - focusing on the value of various nutritional supplements. And they encourage you to take lots of these, based on incomplete research testing each of them separately.
Life Extension Foundation published an aticle in their 2006 Collector's Edition about Vitamin E. They discussed a review article, published in JAMA on August 11, 2004, that "extolled the benefits of gamma tocopherol". I don't have access to this review article, but the basic message in LEF's article is that JAMA validated what LEF has been saying for 8 years. All the studies with negative results for Vitamin E have been testing the wrong form. Alpha tocopherol, especially the artificial form, is not beneficial in large amounts by itself. The gamma form is the better antioxidant. Minimally, you should be taking a mixed form - one that resembles the mix you would find in nuts.
Assuming this is true (still an assumption since the research is not conclusive) this is one illustration of how medical science fumbles. Not that LEF is beyond criticism either - more on that at the end of this post.
Vitamin E research began the way that a lot of medical science begins. Population studies are mined for difference in outcomes. Some examples are the famous "seven countries" study about cholesterol and CHD, the big longitudinal nurses studies - NHANES - for the effects of antioxidants like beta carotene and E, and the lower incidence of CHD in pre-menopausal women.
From this data, a hypothesis is formulated. In all these cases substance "a" prevents disease "b". Because good science - science that will be funded by a review committee and pass muster for publication - prefers double-blind studies that test single substances, these hypotheses often focus on single substances. The bias for single substances also relatest to the drug approval process in the FDA - and patent law. So, a medical researcher will decide to study - and will often announce the finding based on the population studies - whether "a" prevents "b". They will embark on a long series of these studies. Drug companies and food manufacturers will rush to develop products and exploit this. Press interviews and advertising will reinforce this.
Unfortunately, many times it's been found that the single substance doesn't do the advertised job. The hypothesis is apparenly false and the evidence just doesn't hold up.
So, what goes wrong? Perhaps their is no causal relationship - just a correlative one. Maybe the single substance is not responsible for the effect alone. It's part of a complex that is required to have the effect. Sometimes, more is not better. There is a dose dependency - a range of efficacy. Perhaps the testing was often the wrong amounts. And then, the body is a very complex thing, with lots of redundancy and feedback loops.
What harm is done when these hypotheses are interpreted as fact too early? Sometimes, real harm is done when doctors act on the early results, pushed by drug companies eager for profits. HRT is an example. High alpha tocopherol doses increased the incidence of stroke. High beta carotene intake increase lung cancers in smokers.
But another serious casualty is public confidence in science. It makes science look flaky and unreliable. It reinforces the notion that all problems can be cured with a "magic pill". More careful study is needed before acting on these hypotheses.
Why do we do this? Money is one reason. Drug and food companies make money from this. And researchers get funded for these overly simplistic, but conventionally framed hypotheses. And, as Nisbett explains in The Geography of Thought, Westerners prefer the single substance approach to a more Eastern wholistic approach. We tend to ignore the background, the context, the environment. We look for a main character, a hero.
It's this last problem that is the most troubling. If we are always trying to advance medical science by understanding the effects of single substances on health, we may never really understand the system.
So, what's the criticism of LEF? They are all about single substances - focusing on the value of various nutritional supplements. And they encourage you to take lots of these, based on incomplete research testing each of them separately.
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