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Conditions > Clinical Trials.
clinical studies on vitamins flawed by poor methodology - Science Daily,
12/30/13 - "Needed are new methodologies that accurately
measure baseline nutrient levels, provide supplements or dietary changes only to
subjects who clearly are inadequate or deficient, and then study the resulting
changes in their health. Tests must be done with blood plasma or other
measurements to verify that the intervention improved the subjects'
micronutrient status along with biomarkers of health. And other approaches are
also needed that better reflect the different ways in which nutrients behave in
cell cultures, lab animals and the human body ... most large, clinical studies
of vitamins have been done with groups such as doctors and nurses who are
educated, informed, able to afford healthy food and routinely have better
dietary standards than the public as a whole ... More than 90 percent of U.S.
adults don't get the required amounts of vitamins D and E for basic health ...
More than 40 percent don't get enough vitamin C, and half aren't getting enough
vitamin A, calcium and magnesium ... The cancer reduction would be in addition
to providing good basic health by supporting normal function of the body,
metabolism and growth ... If there's any drug out there that can do all this, it
would be considered unethical to withhold it from the general public. But that's
basically the same as recommending against multivitamin/mineral supplements"
Double Espresso vs Prostate Cancer - Medscape, 12/17/10 -
"This wasn't a randomized trial. It was
epidemiologic observational research. What they did was they gave people a
questionnaire about their coffee drinking habits, and then they correlated
that with hospital records on who got advanced prostate cancer and who
didn't. Of course, there's a big problem with doing that type of research,
which is that people who drink coffee may be different from people who don't
drink coffee in all sorts of ways other than their caffeine consumption.
Here's the number-one reason I don't actually believe the study. What the
investigators reported was a 60% decrease in your risk for advanced prostate
cancer if you drank coffee. Finasteride and dutasteride, these are drugs
that we know in randomized trials are effective for prostate cancer, and we
know that they have a mechanism of action that is pertinent to the prostate.
Those 2 drugs reduce the risk for cancer by about 25%. Nothing is going to
reduce the risk for advanced prostate cancer by 60%. I doubt if chemotherapy
would. This is just a guess, little indication that the results of the study
are due to bias ... There's another problem with these sorts of studies.
Cancer takes a long time to develop. In fact, in the case of prostate
cancer, we know that it takes 30 or more years between initiation of cancer
and a clinical diagnosis"
We're so good at medical studies that most of them are wrong -
arstechnica.com, 3/3/10 - "by the time you reach 61
tests, there's a 95 percent chance that you'll get a significant result at
random. And, let's face it—researchers want to see a significant result, so
there's a strong, unintentional bias towards trying different tests until
something pops out ... we simply have to recognize the problem and
communicate it with the public, so that people don't leap to health
conclusions each time a new population study gets published. Medical
researchers recognize the value of replication, and they don't start writing
prescriptions based on the latest gene expression study—they wait for the
individual genes to be validated. As we wait for any sort of reform to
arrive, caution, and explaining to the public the reasons for this caution,
seems like the best we can do"
Are clinical trials short-changing us? - Nutra USA, 12/11/08 -
"The same questions jump to my mind all the time:
Where’s the control group? Are the people in the placebo group actually
taking supplements on the side? How long is the latency period for the
disease in question? ... Let’s address these one by one: ..."
Why Most Published Research Findings Are False - PLoS Medicine, 8/05
New Campaign Focuses On Experiments - Intelihealth, 4/15/02
- What Should You
Know Before Entering a Clinical Trial? - WebMD, 7/23/01
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