February 24th, 2011 by Harriet Hall, M.D. in Health Tips, Research
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I was surprised to get this e-mail from a reader:
Surely, Dr. Hall, the public mania for nutritional supplements is baseless. All the alleged nutrients in supplements are contained in the food we eat. And what governmental agency has oversight responsibility regarding the production of these so-call nutritional supplements? Even if one believes that such pills have value, how can the consumer be assured that the product actually contains what the label signifies? I have yet to find a comment on this subject on your otherwise informative website.
My co-bloggers and I have addressed these issues repeatedly.Peter Lipson covered DSHEA (The Diet Supplement Health and Education Act) nicely. It’s all been said before, but perhaps it needs to be said again — and maybe by writing this post I can make it easier for new readers to find the information.
Food, Medicine, or Something In Between?
The FDA regulates foods and has been instrumental in improving the safety of our food supply. It regulates prescription and over-the-counter medications, requiring evidence of effectiveness and safety before marketing. Surveys have shown that most people falsely assume these protections extend to everything on the shelves including diet supplements, but they don’t.
Under the 1994 Diet Supplement Health and Education Act (DSHEA), a variety of products such as vitamins, minerals, herbs and botanicals, amino acids, enzymes, organ tissues, and hormones can evade the usual controls if they are sold as diet supplements. Under the DSHEA, the manufacturer doesn’t have to prove to the FDA that a product is safe and effective; it is up to the FDA to prove that it isn’t safe, and until recently there was no systematic method of reporting adverse effects (required reporting is still limited to serious effects like death).
So far the FDA has only managed to ban one substance, ephedra, and it took the death of a prominent sports figure and considerable skirmishing with the courts to accomplish that. Independent lab tests of diet supplements have found a high rate of contamination (with things like heavy metals and prescription drugs) and dosages wildly varying from the label. A striking example was Gary Null’s recent poisoning with vitamin D from one of his own products which contained 1,000 times the intended amount.
The FDA has issued rules on good manufacturing practices, but standardization is not required and it remains to be seen whether the new rules will effectively improve product quality. Read more »
*This blog post was originally published at Science-Based Medicine*
February 2nd, 2011 by Harriet Hall, M.D. in Book Reviews, Opinion
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Journalist Gary Taubes created a stir in 2007 with his impressive but daunting 640-page tome Good Calories, Bad Calories. Now he has written a shorter, more accessible book Why We Get Fat: And What to Do About It to take his message to a wider audience. His basic thesis is that:
– The calories-in/calories-out model is wrong.
– Carbohydrates are the cause of obesity and are also important causes of heart disease, type 2 diabetes, cancer, Alzheimer’s, and most of the so-called diseases of civilization.
– A low-fat diet is not healthy.
– A low-carb diet is essential both for weight loss and for health.
– Dieters can satisfy their hunger pangs and eat as much as they want and still lose weight as long as they restrict carbohydrates.
He supports his thesis with data from the scientific literature and with persuasive theoretical arguments about insulin, blood sugar levels, glycemic index, insulin resistance, fat storage, inflammation, the metabolic syndrome, and other details of metabolism. Many readers will come away convinced that all we need to do to eliminate obesity, heart disease and many other diseases is to get people to limit carbohydrates in their diet. I’m not convinced, because I can see some flaws in his reasoning. Read more »
*This blog post was originally published at Science-Based Medicine*
January 20th, 2011 by Harriet Hall, M.D. in Better Health Network, Opinion
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A November letter to the editor in American Family Physician chastises that publication for misusing the term “secondary prevention,” even using it in the title of an article that was actually about tertiary prevention.
I am guilty of the same sin. I had been influenced by simplistic explanations that distinguished only two kinds of prevention: Primary and secondary. I thought primary prevention was for those who didn’t yet have a disease, and secondary prevention was for those who already had the disease, to prevent recurrence or exacerbation. For example, vaccinations would be primary prevention and treatment of risk factors to prevent a second myocardial infarct would be secondary prevention.
No, there are three kinds of prevention: Primary, secondary and tertiary. Primary prevention aims to prevent disease from developing in the first place. Secondary prevention aims to detect and treat disease that has not yet become symptomatic. Tertiary prevention is directed at those who already have symptomatic disease, in an attempt to prevent further deterioration, recurrent symptoms and subsequent events.
Some have suggested a fourth kind, quaternary prevention, to describe “… the set of health activities that mitigate or avoid the consequences of unnecessary or excessive interventions in the health system.” Another version is “Action taken to identify patient at risk of overmedicalisation, to protect him from new medical invasion, and to suggest to him interventions, which are ethically acceptable.” But this is not a generally accepted category. Read more »
*This blog post was originally published at Science-Based Medicine*
January 13th, 2011 by Harriet Hall, M.D. in Book Reviews, Research
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One of our readers suggested that I review the book The Great Influenza: The Epic Story of the Deadliest Plague in History, by John M. Barry. It’s not a new book (it was published in 2004) but it is very pertinent to several of the issues that we have been discussing on this blog, especially in regards to the current anti-vaccine movement. It’s well worth reading for its historical insights, for its illumination of the scientific method, and for its accurate reporting of what science has learned about influenza.
In the great flu epidemic of 1918, influenza killed as many people in 24 weeks as AIDS has killed in 24 years. It’s hard to even imagine what that must have been like, but this book helps us imagine it. It tells horror stories: Children found alone and starving beside the corpses of their parents in homes where all the adults had died, decomposing bodies piling up because there was no one left who was healthy enough to bury them.
Sometimes the disease developed with stunning rapidity: During one three-mile streetcar trip, the conductor, three passengers, and the driver died. In another incident, apparently healthy soldiers were being transferred to a new post by train: During the trip, men started coughing, bleeding, and collapsing; and by the time it arrived at its destination, 25 percent of the soldiers were so sick they had to be taken directly from train to hospital. Two-thirds of them were eventually hospitalized in all, and 10 percent of them died. The mind boggles. Read more »
*This blog post was originally published at Science-Based Medicine*
December 30th, 2010 by Harriet Hall, M.D. in Better Health Network, Book Reviews, Opinion, Research
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Myths and misconceptions about cancer abound. Oncologists are frequently criticized for torturing patients by burning, cutting and poisoning without making any real progress in the war against cancer. Siddhartha Mukherjee, an oncologist and cancer researcher, tries to set the record straight with his new book The Emperor of All Maladies: A Biography of Cancer.
It is a unique combination of insightful history, cutting edge science reporting, and vivid stories about the individuals involved: The scientists, the activists, the doctors, and the patients. It is also the story of science itself: How the scientific method works and how it developed, how we learned to randomize, do controlled trials, get informed consent, use statistics appropriately, and how science can go wrong. It is so beautifully written and so informative that when I finished it I went back to page one and read the whole thing again to make sure I hadn’t missed anything. I enjoyed it just as much the second time. Read more »
*This blog post was originally published at Science-Based Medicine*
