We do not always need a definitive RCT to know what we know; and I make a living running such trials. Suppose you wanted to know with something nearing certainty what specific dietary pattern was best for human health. How would you proceed?
First, you would need to define best in an operational (i.e., measurable) way. Does best mean lowers LDL in the short term, or does it mean raises HDL, or both? Does it mean it lowers inflammatory markers, or insulin, or blood glucose, or blood pressure? Does it mean all of these, or does it mean something else? Is the short term one month, or three, or a year?
I dont think any of these, or anything like them, really satisfies what we think we mean when we say best for health. I think the intended meaning of that is actually rather clear: the combination of longevity, and vitality. Years in life, and life in years, if you will. I think a diet is best for health and yes, I have wrestled with this very issue before if it fuels a long, robust life free of preventable chronic diseases (e.g., heart disease, cancer, stroke, diabetes, dementia, etc.) and obesity, and endows us with the energy both mental and physical- to do all we want and aspire to do. That, I think, is a robust definition of best for health.
We are obligated to wrestle comparably with the operational definition of a specific diet. Low fat, or low carb dont mean much. A low fat diet could be rich in beans and lentils, or made up exclusively of lollipops. A low carb diet could cut out refined starch and added sugar, or exclude all fruits and vegetables. Lets not belabor this, and simply concede that the relevant test to prove that one, specific dietary prescription (e.g., the Ornish diet, or the South Beach diet, or the DASH diet, etc.) is best is to establish optimized versions of the various contenders, from vegan to Paleo, and put them up against one another directly.
Advertisement
And now our tribulations begin. As we noted at the start, our outcome is the combination of longevity and vitality. To get at longevity, we need a very long trial; in fact, our trial needs to last a lifetime. So, just to get started, we are toying with the notion of a randomized trial running for 80 to 100 years.
Since we are comparing optimal versions of diets reasonably under consideration for best diet laurels, we may anticipate that our study participants are apt to be healthier, and longer-lived in general than the population at large, consuming the lamentable typical American diet.
Thats a problem too. If our entire study sample does well, it raises the bar to show that one of our diets is truly, meaningfully better than another. The smaller the difference we are seeking, the larger the sample size we need to find it. That now means we need not only a RCT unprecedented in length, but unprecedented in size, too. We need to randomize tens of thousands, if not hundreds of thousands to study the effects of competing diets on vitality and longevity at a cost that is staggering to contemplate, and would certainly run into the billions of dollars.
This study has not been done. This study will not be done. But, so what?
Lets contrast our ostensible need for this RCT to how we know what we know about putting out house fires. There has never been, to the best of my knowledge, a RCT to show that water is a better choice than gasoline. Do you think we need such a trial, to establish the legitimacy of the basic theme (i.e., use water) of the right approach? Would you, and your home, be willing to participate in such a trial when you call 911 knowing you might randomly be assigned to the gasoline arm of the study?
I trust we agree that observation, experience, and sense serve to establish beyond the realm of reasonable (or, even, any) doubt that water is generally good for putting out house fires, and gasolinenot so much.
My friends diet is the same. The want of a RCT addressing this kind of water versus that does not mire us in perpetual cluelessness about the basic approach to putting out fires. Sure, we could do RCTs to add to what we know, but the want of such studies does not expunge what we already know based on empirical evidence, long experience, observation, and sense.
A diet comprised principally of minimally processed vegetables, fruits, whole grains, beans, lentils and pulses, nuts, seeds, with plain water preferentially for thirst is the best theme for human and planetary health alike, and runs commonly through all the legitimate, specific contestants, just as water is the best theme when aiming a fire hose. To conclude otherwise is to misconstrue the utility of randomized trials, succumb to their tyranny, and lose our way in a bog of tribulations.
Dr. David L. Katz, http://www.davidkatzmd.com; is founder, True Health Initiative.
View post:
Dr. David Katz, Preventative Medicine: Diet Trial Tribulations - New Haven Register
- Yes, But. The Annotated Atlantic. - November 7th, 2009 [November 7th, 2009]
- Health Insurance Benefit Costs by Region - November 8th, 2009 [November 8th, 2009]
- For an Operator, Please Press... - November 8th, 2009 [November 8th, 2009]
- Pollyanna With a Pen: Maine Governor Signs 18 New Health Care Bills into Law - November 8th, 2009 [November 8th, 2009]
- AMA Sounds the Alarm, Medicare Making Yet Another Attempt to Cut Reimbursement - November 8th, 2009 [November 8th, 2009]
- Mass Governor Asks Blue Cross to Keep Higher Employer Contribution - November 8th, 2009 [November 8th, 2009]
- Lifespan and Care New England Plan Monopoly (Again) - November 8th, 2009 [November 8th, 2009]
- Dirigo Health: Con Artists, Liars, and Thieves? - November 8th, 2009 [November 8th, 2009]
- New Orleans: Health Challenges - November 8th, 2009 [November 8th, 2009]
- August a Flurry of Activity - November 8th, 2009 [November 8th, 2009]
- Maine's Dirigo Health Savings One-Third of Original Estimate - November 8th, 2009 [November 8th, 2009]
- “Methodolatry”: My new favorite term for one of the shortcomings of evidence-based medicine - November 8th, 2009 [November 8th, 2009]
- Suzanne Somers’ Knockout: Dangerous misinformation about cancer (part 1) - November 8th, 2009 [November 8th, 2009]
- A science-based blog about GMO - November 8th, 2009 [November 8th, 2009]
- A Not-So-Split Decision - November 8th, 2009 [November 8th, 2009]
- Military Medicine in Iraq - November 8th, 2009 [November 8th, 2009]
- The effective wordsmithing of Amy Wallace - November 8th, 2009 [November 8th, 2009]
- A Science Lesson from a Homeopath and Behavioral Optometrist - November 8th, 2009 [November 8th, 2009]
- Join CFI in opposing funding mandates for quackery in health care reform - November 8th, 2009 [November 8th, 2009]
- Mainstreaming Science-Based Medicine: A Novel Approach - November 8th, 2009 [November 8th, 2009]
- Those who live in glass houses… - November 8th, 2009 [November 8th, 2009]
- J.B. Handley of the anti-vaccine group Generation Rescue: Misogynistic attacks on journalists who champion science - November 8th, 2009 [November 8th, 2009]
- When homeopaths attack medicine and physics - November 8th, 2009 [November 8th, 2009]
- The cancer screening kerfuffle erupts again: “Rethinking” screening for breast and prostate cancer - November 8th, 2009 [November 8th, 2009]
- All Medicines Are Poison! - November 8th, 2009 [November 8th, 2009]
- When Loud Wins: Will Your Tax Dollars Pay For Prayer? - November 8th, 2009 [November 8th, 2009]
- It’s All in Your Head - November 8th, 2009 [November 8th, 2009]
- The Skeptical O.B. joins the Science-Based Medicine crew - November 8th, 2009 [November 8th, 2009]
- The Tragic Death Toll of Homebirth - November 8th, 2009 [November 8th, 2009]
- What’s the right C-section rate? Higher than you think. - November 8th, 2009 [November 8th, 2009]
- Recombinant Human Antithrombin – Milking Nanny Goats for Big Bucks - December 13th, 2009 [December 13th, 2009]
- Does C-section increase the rate of neonatal death? - December 13th, 2009 [December 13th, 2009]
- Man in Coma 23 Years – Is He Really Conscious? - December 13th, 2009 [December 13th, 2009]
- Why Universal Hepatitis B Vaccination Isn’t Quite Universal - December 13th, 2009 [December 13th, 2009]
- Ontario naturopathic prescribing proposal is bad medicine - December 13th, 2009 [December 13th, 2009]
- Naturopaths and the anti-vaccine movement: Hijacking the law in service of pseudoscience - December 13th, 2009 [December 13th, 2009]
- The Institute for Science in Medicine enters the health care reform fray - December 13th, 2009 [December 13th, 2009]
- Neti pots – Ancient Ayurvedic Treatment Validated by Scientific Evidence - December 13th, 2009 [December 13th, 2009]
- Early Intervention for Autism - December 13th, 2009 [December 13th, 2009]
- A temporary reprieve from legislative madness - December 13th, 2009 [December 13th, 2009]
- A critique of the leading study of American homebirth - December 13th, 2009 [December 13th, 2009]
- Lose those holiday pounds - December 13th, 2009 [December 13th, 2009]
- Endocrine disruptors—the one true cause? - December 13th, 2009 [December 13th, 2009]
- Acupuncture for Chronic Prostatitis/Chronic Pelvic Pain Syndrome - December 13th, 2009 [December 13th, 2009]
- Evidence in Medicine: Experimental Studies - December 13th, 2009 [December 13th, 2009]
- Midwives and the assault on scientific evidence - December 13th, 2009 [December 13th, 2009]
- The Mammogram Post-Mortem - December 13th, 2009 [December 13th, 2009]
- An Influenza Recap: The End of the Second Wave - December 13th, 2009 [December 13th, 2009]
- The End of Chiropractic - December 13th, 2009 [December 13th, 2009]
- Cell phones and cancer again, or: Oh, no! My cell phone’s going to give me cancer! (revisited) - December 20th, 2009 [December 20th, 2009]
- Another wrinkle to the USPSTF mammogram guidelines kerfuffle: What about African-American women? - December 20th, 2009 [December 20th, 2009]
- Acupuncture, the P-Value Fallacy, and Honesty - December 20th, 2009 [December 20th, 2009]
- The One True Cause of All Disease - December 20th, 2009 [December 20th, 2009]
- Communicating with the Locked-In - December 20th, 2009 [December 20th, 2009]
- Are the benefits of breastfeeding oversold? - December 20th, 2009 [December 20th, 2009]
- Measles - December 20th, 2009 [December 20th, 2009]
- Radiation from medical imaging and cancer risk - December 21st, 2009 [December 21st, 2009]
- Multiple Sclerosis and Irrational Exuberance - December 21st, 2009 [December 21st, 2009]
- Medical Fun with Christmas Carols - December 22nd, 2009 [December 22nd, 2009]
- Lithium for ALS – Angioplasty for MS - December 23rd, 2009 [December 23rd, 2009]
- “Toxins”: the new evil humours - December 24th, 2009 [December 24th, 2009]
- 2009’s Top 5 Threats To Science In Medicine - December 24th, 2009 [December 24th, 2009]
- Buteyko Breathing Technique – Nothing to Hyperventilate About - December 26th, 2009 [December 26th, 2009]
- The Graston Technique – Inducing Microtrauma with Instruments - December 29th, 2009 [December 29th, 2009]
- The “pharma shill” gambit - December 29th, 2009 [December 29th, 2009]
- Ginkgo biloba – No Effect - December 30th, 2009 [December 30th, 2009]
- Oppose “Big Floss”; practice alternative dentistry - January 1st, 2010 [January 1st, 2010]
- Causation and Hill’s Criteria - January 3rd, 2010 [January 3rd, 2010]
- The life cycle of translational research - January 10th, 2010 [January 10th, 2010]
- The anti-vaccine movement strikes back against Dr. Paul Offit - January 10th, 2010 [January 10th, 2010]
- Osteoporosis Drugs: Good Medicine or Big Pharma Scam? - January 10th, 2010 [January 10th, 2010]
- Acupuncture for Hot Flashes - January 10th, 2010 [January 10th, 2010]
- The case for neonatal circumcision - January 10th, 2010 [January 10th, 2010]
- A victory for science-based medicine - January 10th, 2010 [January 10th, 2010]
- James Ray and testosterone replacement therapy (TRT) - January 10th, 2010 [January 10th, 2010]
- The Water Cure: Another Example of Self Deception and the “Lone Genius” - January 12th, 2010 [January 12th, 2010]
- Be careful what you wish for, Dr. Dossey, you just might get it - January 13th, 2010 [January 13th, 2010]
- You. You. Who are you calling a You You? - January 15th, 2010 [January 15th, 2010]
- The War on Salt - January 16th, 2010 [January 16th, 2010]
- Is breech vaginal delivery safe? - January 16th, 2010 [January 16th, 2010]