Chicken Little

Clinical studies can be designed in a number of ways. The ease and cost of these studies differ dramatically, as does the confidence of the findings.

The most confident way to design a clinical study is to tell neither the participants nor the investigator(s) what treatment is being offered, then to administer treatment or placebo. Neither the people doing the research nor the participants know what they are receiving. Of course, there needs to be some way to find out what was given at the end of the study in order to analyze the outcome.

This is called a “double-blind, placebo-controlled” clinical study. While not perfect since it tends to examine a treatment phenomenon in isolation (e.g., the effects of a single drug in a select group of people), it is the best sort of study design that is most likely to yield confident results, both negative and positive. This sort of design is followed, for instance, for most prescription drugs.

There are pitfalls in such studies, of course, and some have made headlines lately. For instance, beyond tending to examine single conditions in a select group of participants, a double-blind, placebo-controlled study can also fail to uncover rare effects. If a study contains 5000 participants, for instance, but a rare complication develops in 1 person out of 20,000, then it’s unlikely such an ill-effect will be observed until larger numbers of people are exposed to the agent.

Another pitfall (though not so much of study design, but of human greed) is that study outcomes that are not favorable can be suppressed by simply failing to publish the results. This has undoubtedly happened numerous times over the years. For this reason, a registry has been created for all human clinical trials as a means to enforce publication of outcomes, both favorable and unfavorable.

Despite its weaknesses, the double-blind, placebo-controlled study design remains the most confident way to show whether or not some treatment does indeed yield some effect. It is less prone to bias from either the participant or the investigator. Human nature being what it is, we tend to influence results just to suit our particular agenda or interests. An investigator who knows what you are given, drug or placebo, but owns lots of stock in the company, or is hoping for special favors from the pharmaceutical company sponsor, for instance, is likely to perceive events in a light favorable to the outcome of the study.

Now, most studies are not double-blind, placebo-controlled studies. These are notoriously difficult studies to engineer; raise lots of ethical questions (can you not treat a person with an aggressive cancer, for instance, and administer a placebo?); often require substantial numbers of participants (thousands), many of whom may insist on payment for devoting their time, bodies, and perhaps even encountering some risk; and are tremendously expensive, costing many tens of millions of dollars.

For this reason, many other study designs are often followed. They are cheaper, quicker, may not even require the active knowledge or participation of the group being studied. That’s not to say that the participants are being tricked. It may simply be something like trying to determine if there are more heart attacks in people who live in cities compared to rural areas by comparing death rates from heart attack from public records and population demographic data. Or, a nutritional study could be performed by asking people how many eggs they eat each week and then contacting them every month for 5 years to see if they’ve had a heart attack or other heart event. No treatment is introduced, no danger is added to a person’s established habits. Many epidemiologic studies are performed this way.

The problem is that these other sorts of study designs, because they generate less confident results, are not generally regarded as proof of anything. They can only suggest the possibility of an association, an hypothesis. For real proof to occur, a double-blind, placebo-controlled may need to follow. Alternatively, if an association suggested by a study of lesser design might, by reasons of a very powerful effect, be sufficient. But this is rare. Thalidomide and catastrophic birth defects are an example of an association between a drug and fetal limb malformation that was so clear-cut that no further investigation was required to establish a causative association. Of course, no one in their right mind would even suggest a blinded study.

Where am I going with this tedious rambling? Lately, the media has been making a big to-do about several studies, none of which are double-blind, placebo-controlled, but were cross-sectional sorts of observations, the sorts of studies which can only suggest an effect. This happened with Dr. Steve Nissen’s study of Avandia (rosiglitazone) for pre-diabetes and risk for heart attack and the recent study suggesting that cancer incidence is increased when LDL cholesterol is low. Both were observations that suggested such associations.

Now, those of you following the Heart Scan Blog or the www.cureality.com website know that we do not defend drug companies nor their drugs. In fact, we’ve openly and repeatedly criticized the drug industry for many of its practices. Drugs are, in my opinion, miserably overused and abused.

But, as always, I am in the pursuit of truth. Neither of these studies, in my view, justified the sort of media attention they received. They are hypothesis-generating efforts—that’s it. You might argue that the questions raised are so crucial that any incremental risk of a drug is simply not worth it.

Despite the over-reaction to these studies, good will come of the fuss. I do believe that heightened scrutiny of the drug industry will result. Many people will seek to avoid prescription drugs and opt for healthy changes in lifestyle, thus reducing exposure to costs and side-effects.

But beware of the media, acting as our Chicken Little, reporting on studies that prove nothing but only raise questions.

Comments (1) -

  • jpatti

    9/11/2007 10:26:00 AM |

    There's another issue with double-blind studies, for things other than drugs or supplements, they're impossible.  

    Your example of the number of eggs in a person's diet is a good example; there's no "placebo" for eggs.  Similarly, if I increase my level of exercise, I notice that - it can't be blinded.  For diet and other lifestyle changes, we will never be able to gain the amount of evidence as for drug trials.

    I think this is why many doctors don't think so much about prescribing these types of things, except for a cursory instruction to "eat better, lose weight and exercise," they're just not as strongly convinced of the benefit of these changes because they can't be proven as strongly.  But... not being able to prove something doesn't mean it's not important to health!  

    As a diabetic, I measure my bg multiple times a day and make changes to my food intake, exercise and medication dosage to hit established bg goals.  While I think tightly-controlling bg is probably the number one thing I can do for my heart health, it can never be proven in a double-blind study.

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When meat is not just meat

When meat is not just meat


The edgy nutrition advocate, Mike Adams, over at NewsTarget.com came up with this scary photo tour of a processed meat product from Oscar Mayer: Mystery Meat Macrophotography: A NewsTarget PhotoTour by Mike Adams







Along with increasingly close-up photographs of this meat-product, Adams lists the ingredients in Oscar Mayer's Cotto Salami:


Beef hearts
Pork
Water
Corn syrup
Beef

Contains less than 2% of:
Salt
Sodium lactate
Flavor
Sodium phosphates
Sodium diacetate
Sodium erythorbate
Dextrose
Sodium nitrite
Soy lecithin
Potassium phosphate
Potassium chloride
Sugar


As I reconsider the role of saturated fat in diet, given the startlingly insightful discussion by Gary Taubes of Good Calories, Bad Calories, I am reminded that not all meat is meat, not all saturated fat sources are equal.

I am concerned in particular about sodium nitrite content, a color-fixer added to cured meats that caused a stir in the 1970s when data suggesting a carcinogenic effect surfaced. The public's effort to remove sodium nitrite from the food supply was vigorously opposed by the meat council and it remains in cured meats like sausage, hot dogs, and processed meats like Cotto Salami. A 2006 meta-analysis (combined analysis of studies) of 63 studies did indeed suggest that sodium nitrite was related to increased risk of gastric cancer. This argument is plausible from animal models of cancer risk, as 40 animal models have likewise suggested the same carcinogenic association.

Also, fructose? This is most likely added for sweetness. Recall that fructose heightens appetite and raises triglycerides substantially.

I personally have a natural aversion to meat. I don't like the taste, the look, smell, and the thought of what the animal went through to make it to the supermarket. But, considered from the cold, carnivorous viewpoint of the question, "Is meat okay to eat?", among the issues to consider is whether the meat has been cured or processed, and does that process include addition of sodium nitrite.

Cotto Salami and similar products are not, of course, what carnivorous humans in the wild ate. This is a processed, modified product created from factory farm animals raised in cramped conditions and fed corn and other cheap, available foods. It is not created from free-ranging animals wandering their pastures or pens, eating diets nature intended. This results in modified fat composition, not to mention hormones and antibiotics added. These are not listed on the ingredients. Wild meat does not contain fructose or color-fixers, either.

So don't mistake "meat" in your grocery store for meat. It might look and smell the same--until you look a little closer.



Copyright 2007 William Davis, MD

Comments (7) -

  • Nancy M.

    12/18/2007 3:04:00 PM |

    Wasn't Good Calories, Bad Calories good?  Man, just what the medical world needs, a good wake-up call into how schlocky their science is (sometimes).  

    Did you finish the book yet?  Parts of it infuriated me at the stupidity and arrogance of people.  And I have to say it is getting harder and harder to have respect for medical "authorities" when you know the horrible science their training was based on, that they don't question the basis for these assumptions yet assume their patients are all idiots.

    I'd love to hear more of your comments on his book if you get a chance to blog about them.

  • MAC

    12/18/2007 3:05:00 PM |

    Would be interested in any comments you have as you "reconsider the role of saturated fat in diet" as a low carb diet appears to be beneficial in raising HDL.

    This research  from Jeff Volek was of interest: Jeff Volek, et al: Low carb diet reduces inflammation and blood saturated fat in Metabolic Syndrome. http://www.sciencedaily.com/releases/2007/12/071203091236.htm

    Also, Cordain makes the case in his FAQ for the Paleo Diet that saturated fat averaged 11% in wild animal carcasses.

  • Ross

    12/18/2007 5:50:00 PM |

    If you're going to buy something like salami, ham, bacon, sausage, or other meat product, the best source is often a deli that makes it on site.  Not only will the salami, ham, or sausage be made with fewer ingredients, but it's much tastier, fresher, and often a similar cost to mass-marketed processed meats.  

    This will not be practical for people everywhere.  Living in LA as I do, there are specialty delis all over the place and it isn't too hard to find locally made sausage, etc.  One alternative would be a deli that takes great pride in presenting the craft-made meat products of a smaller supplier.

    I've actually ignored what might be the best option of all, which is to make it yourself.  Simple ham, proscuitto, bacon, salami, many different kinds of sausage, etc. can all be made in the home with inexpensive tools and (for proscuitto and salami) a decent dry place where they won't be disturbed.  It's also fun!

    But at all costs, avoid anything made by oscar mayer or any other mass produced meat product.  It's all crap.

  • chickadeenorth

    12/20/2007 5:26:00 AM |

    Even Dr Atkins said no meats allowed that are processed or have nitrates, only meats like our ancestors ate, he said it was like "the kiss of death".I don't even considered those types of meat to have sat fats, but poision, they are all part of Franken foods to me, like Snackwell cookies.. If I have sausage I get a local German butcher to make organic elk meat into garlic sausage for us.To me low carb means nutrient dense whole foods.

  • Dr. Davis

    12/20/2007 5:36:00 AM |

    What's frightening is that, whenever I've discussed the Atkins' approach with people doing it on their own, they've virtually always included plentiful cured and processed meats.

    Somehow that part of the message didn't get stressed enough.

  • Dr. Davis

    12/20/2007 5:38:00 AM |

    In response to Nancy's first post:

    I'm embarassed to admit that Taubes was so tremendously unique and entertaining (in a nerdy sort of way) that I've savored each discussion slowly and carefully. So it's literally taken me two months to read his book. But I have enjoyed every word.

  • chickadeenorth

    12/21/2007 7:21:00 AM |

    Yes I think those of us who used the board and forum understood it better and we could call his office and talk to his nurse or leave him a question, lots misconstrued they should eat a lb  bacon a day, He said no nitrates and sat fats under 20 gr a day.I learned his big boo boo was eventually incorporating rungs adding breads, potatoes etc, they are the kiss of death IMHO.

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