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Monday, March 31, 2014

Gills, pills and obesity genes

Two new studies, just published online in JAMA Pediatrics, may have us fired up yet again about the genetic variation to blame for obesity. But then again, is that really the problem?

One of the studies examined variation in food and satiety responses, which we may summarize as appetite, in roughly 400 pairs of 3-month-old twins in the U.K., and tracked growth and development over time. There are always lots of important details in biomedical research, but the perhaps predictable punch line was this: the babies with the heartier appetites gained the more weight.

The second study was directed at the same basic issue, but went a bit deeper. Investigators again examined the association between appetite and weight gain in a group of over 2000 twin children in the U.K., but this team included an assessment of genes associated with variation in satiety responses, essentially how much eating it takes to feel full. Once again, more appetite meant more weight gain. But this time, more genes for more appetite was identified as the real culprit.

Finally, an accompanying editorial noted the importance of this kind of genetic research because the obesigenic environment “does not affect all children equally.”

That is undeniably true. It is equally true that the sinking of the Titanic did not affect all passengers equally. More generally, falling into water does not affect all human beings equally. Some of us know how to swim, and some do not. Some of us can hold our breath longer than others.

And while there is, I am quite confident, genetic variability we could find and associate with variation in how long we can hold our breath, I am not sure how illuminating that would truly be about the risk of drowning.

Human beings are vulnerable to drowning because we don’t have gills, and the reason absolutely resides in our genes. We have Homo sapien genes that include the recipe for lungs, and exclude the recipe for gills. In contrast, blue fin tuna and guppy genes reliably include the recipe for gills and exclude the recipe for lungs. Blue fin tuna and guppies have just the kind of trouble out of water that we are prone to have in it. We don’t have gills because we aren’t fish, and fish don’t have lungs because they aren’t people. And in both cases, the reason we aren’t them and they aren’t us resides in our respective genes.

Given that, if we approached drowning like obesity, we would go looking for those genes. We would, readily, find the divergences between human and guppy genes. And we might, I suppose, declare that a genetic basis for drowning had been identified. And once genes were indicted for drowning, we could head off down the path of drug development or genetic engineering to deal with the problem.

Hold that thought, if not your breath, and let’s probe the corresponding depths.

Imagine a people on some imaginary world that lived on a great landmass, far from any body of water, evolving and adapting accordingly throughout their long history. Then imagine that, after however many eons in their native land-locked state, and for reasons we may ignore or guess at, these people set off on an excursion, and encounter the sea for the first time. They knew water, of course, because they drank it like we do, but they had never before seen any body of water larger than a puddle.

Imagine that these pioneers were intrigued by the sea, and therefore boldly wandered in. Having no experience with matters maritime, and knowing nothing about swimming, several of them drowned. Several others nearly drowned, but managed to climb out in the nick of time.

And then imagine, rather than reaching any fundamental conclusions about the interactions of their kind with large bodies of water, these sagacious people scratched their extra-terrestrial heads and said something like (in whatever language they speak): “When we wander into that enormous puddle, some of us die and some of us don’t. Clearly, then, there must be variation in our go-forth-into-enormous-puddle genes. Let us study our genes and look for that variation so we may better understand what happened here today. Then, perhaps, we might find a way to fix the go-not-into-great-puddles-or-you-will-surely-drown genes, as those must be defective. After all, a few of us went into the big puddle and lived. Surely there must be some way for us all to have those wonderful you-will-only-almost-die-if-you-go-into-great-puddle genes. “

Gazing at these counterparts across the cosmos, they look rather like nincompoops, don’t they?

I am not refuting the value in these new studies. The editorialist very appropriately notes that early identification of genetic vulnerability to weight gain might allow for very early implementation of prevention strategies, so that obesity does not develop in the first place.

I like that, but do we really need maps of our kids’ genomes to take such action? We have pandemic childhood obesity right now, meaning legions of kids around the world are vulnerable to weight gain, whatever their genes. And yet, we routinely feed them junk. We routinely jettison physical activity from their daily routines. We peddle to them foods willfully designed to be irresistible if not addictive, and to maximize the number of calories it takes to feel full. Can we really justify the lunacy of a culture that studies genes looking for variation in satiety responses, while engineering foods to undermine satiety responses?

Yes, our genetic vulnerability to obesity is variable, much, I bet, like our genetic vulnerability to drowning. But I don’t think that invites a genetic study of the drowning victims of the Titanic. I think the bigger issue was the obvious one: the ship went down.

We are all in the same boat, and it’s sinking, too, as evidence by a global rise in bariatric surgery for ever younger children. The genes underlying vulnerability to obesity in all their variation were there a generation or two or twenty ago, too, when childhood obesity was rare. Those same genes are there now that it is rampant. Knowledge of them may be put to good use, but not if it distracts us from the sinking ship. What has changed is not within our children, but all around them. And we don’t need to wait for a genetic map of each child to fix it.

Human beings don’t have gills, and there are genes to blame. But the right response looks like swimming lessons, and lifeguards, and fences around pools, not studying genes while pushing kids into the surf. Not a new pill to fix an age-old part of who we are that was never really broken.

David L. Katz, MD, FACP, MPH, FACPM, is an internationally renowned authority on nutrition, weight management, and the prevention of chronic disease, and an internationally recognized leader in integrative medicine and patient-centered care. He is a board certified specialist in both Internal Medicine, and Preventive Medicine/Public Health, and Associate Professor (adjunct) in Public Health Practice at the Yale University School of Medicine. He is the Director and founder (1998) of Yale University's Prevention Research Center; Director and founder of the Integrative Medicine Center at Griffin Hospital (2000) in Derby, Conn.; founder and president of the non-profit Turn the Tide Foundation; and formerly the Director of Medical Studies in Public Health at the Yale School of Medicine for eight years. This post originally appeared on his blog at The Huffington Post.

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Blog log

Members of the American College of Physicians contribute posts from their own sites to ACP Internistand ACP Hospitalist. Contributors include:

Albert Fuchs, MD
Albert Fuchs, MD, FACP, graduated from the University of California, Los Angeles School of Medicine, where he also did his internal medicine training. Certified by the American Board of Internal Medicine, Dr. Fuchs spent three years as a full-time faculty member at UCLA School of Medicine before opening his private practice in Beverly Hills in 2000.

And Thus, It Begins
Amanda Xi, ACP Medical Student Member, is a first-year medical student at the OUWB School of Medicine, charter class of 2015, in Rochester, Mich., from which she which chronicles her journey through medical training from day 1 of medical school.

Auscultation
Ira S. Nash, MD, FACP, is the senior vice president and executive director of the North Shore-LIJ Medical Group, and a professor of Cardiology and Population Health at Hofstra North Shore-LIJ School of Medicine. He is Board Certified in Internal Medicine and Cardiovascular Diseases and was in the private practice of cardiology before joining the full-time faculty of Massachusetts General Hospital.

Zackary Berger
Zackary Berger, MD, ACP Member, is a primary care doctor and general internist in the Division of General Internal Medicine at Johns Hopkins. His research interests include doctor-patient communication, bioethics, and systematic reviews.

Controversies in Hospital Infection Prevention
Run by three ACP Fellows, this blog ponders vexing issues in infection prevention and control, inside and outside the hospital. Daniel J Diekema, MD, FACP, practices infectious diseases, clinical microbiology, and hospital epidemiology in Iowa City, Iowa, splitting time between seeing patients with infectious diseases, diagnosing infections in the microbiology laboratory, and trying to prevent infections in the hospital. Michael B. Edmond, MD, FACP, is a hospital epidemiologist in Richmond, Va., with a focus on understanding why infections occur in the hospital and ways to prevent these infections, and sees patients in the inpatient and outpatient settings. Eli N. Perencevich, MD, ACP Member, is an infectious disease physician and epidemiologist in Iowa City, Iowa, who studies methods to halt the spread of resistant bacteria in our hospitals (including novel ways to get everyone to wash their hands).

db's Medical Rants
Robert M. Centor, MD, FACP, contributes short essays contemplating medicine and the health care system.

Suneel Dhand, MD, ACP Member
Suneel Dhand, MD, ACP Member, is a practicing physician in Massachusetts. He has published numerous articles in clinical medicine, covering a wide range of specialty areas including; pulmonology, cardiology, endocrinology, hematology, and infectious disease. He has also authored chapters in the prestigious "5-Minute Clinical Consult" medical textbook. His other clinical interests include quality improvement, hospital safety, hospital utilization, and the use of technology in health care.

DrDialogue
Juliet K. Mavromatis, MD, FACP, provides a conversation about health topics for patients and health professionals.

Dr. Mintz' Blog
Matthew Mintz, MD, FACP, has practiced internal medicine for more than a decade and is an Associate Professor of Medicine at an academic medical center on the East Coast. His time is split between teaching medical students and residents, and caring for patients.

Everything Health
Toni Brayer, MD, FACP, blogs about the rapid changes in science, medicine, health and healing in the 21st century.

FutureDocs
Vineet Arora, MD, FACP, is Associate Program Director for the Internal Medicine Residency and Assistant Dean of Scholarship & Discovery at the Pritzker School of Medicine for the University of Chicago. Her education and research focus is on resident duty hours, patient handoffs, medical professionalism, and quality of hospital care. She is also an academic hospitalist.

Glass Hospital
John H. Schumann, MD, FACP, provides transparency on the workings of medical practice and the complexities of hospital care, illuminates the emotional and cognitive aspects of caregiving and decision-making from the perspective of an active primary care physician, and offers behind-the-scenes portraits of hospital sanctums and the people who inhabit them.

Gut Check
Ryan Madanick, MD, ACP Member, is a gastroenterologist at the University of North Carolina School of Medicine, and the Program Director for the GI & Hepatology Fellowship Program. He specializes in diseases of the esophagus, with a strong interest in the diagnosis and treatment of patients who have difficult-to-manage esophageal problems such as refractory GERD, heartburn, and chest pain.

I'm dok
Mike Aref, MD, PhD, FACP, is an academic hospitalist with an interest in basic and clinical science and education, with interests in noninvasive monitoring and diagnostic testing using novel bedside imaging modalities, diagnostic reasoning, medical informatics, new medical education modalities, pre-code/code management, palliative care, patient-physician communication, quality improvement, and quantitative biomedical imaging.

Informatics Professor
William Hersh, MD, FACP, Professor and Chair, Department of Medical Informatics & Clinical Epidemiology, Oregon Health & Science University, posts his thoughts on various topics related to biomedical and health informatics.

David Katz, MD
David L. Katz, MD, MPH, FACP, is an internationally renowned authority on nutrition, weight management, and the prevention of chronic disease, and an internationally recognized leader in integrative medicine and patient-centered care.

Just Oncology
Richard Just, MD, ACP Member, has 36 years in clinical practice of hematology and medical oncology. His blog is a joint publication with Gregg Masters, MPH.

KevinMD
Kevin Pho, MD, ACP Member, offers one of the Web's definitive sites for influential health commentary.

MD Whistleblower
Michael Kirsch, MD, FACP, addresses the joys and challenges of medical practice, including controversies in the doctor-patient relationship, medical ethics and measuring medical quality. When he's not writing, he's performing colonoscopies.

Medical Lessons
Elaine Schattner, MD, FACP, shares her ideas on education, ethics in medicine, health care news and culture. Her views on medicine are informed by her past experiences in caring for patients, as a researcher in cancer immunology, and as a patient who's had breast cancer.

Mired in MedEd
Alexander M. Djuricich, MD, FACP, is the Associate Dean for Continuing Medical Education (CME), and a Program Director in Medicine-Pediatrics at the Indiana University School of Medicine in Indianapolis, where he blogs about medical education.

More Musings
Rob Lamberts, MD, ACP Member, a med-peds and general practice internist, returns with "volume 2" of his personal musings about medicine, life, armadillos and Sasquatch at More Musings (of a Distractible Kind).

Prescriptions
David M. Sack, MD, FACP, practices general gastroenterology at a small community hospital in Connecticut. His blog is a series of musings on medicine, medical care, the health care system and medical ethics, in no particular order.

Reflections of a Grady Doctor
Kimberly Manning, MD, FACP, reflects on the personal side of being a doctor in a community hospital in Atlanta.

The Blog of Paul Sufka
Paul Sufka, MD, ACP Member, is a board certified rheumatologist in St. Paul, Minn. He was a chief resident in internal medicine with the University of Minnesota and then completed his fellowship training in rheumatology in June 2011 at the University of Minnesota Department of Rheumatology. His interests include the use of technology in medicine.

Technology in (Medical) Education
Neil Mehta, MBBS, MS, FACP, is interested in use of technology in education, social media and networking, practice management and evidence-based medicine tools, personal information and knowledge management.

Peter A. Lipson, MD
Peter A. Lipson, MD, ACP Member, is a practicing internist and teaching physician in Southeast Michigan. The blog, which has been around in various forms since 2007, offers musings on the intersection of science, medicine, and culture.

Why is American Health Care So Expensive?
Janice Boughton, MD, FACP, practiced internal medicine for 20 years before adopting a career in hospital and primary care medicine as a locum tenens physician. She lives in Idaho when not traveling.

World's Best Site
Daniel Ginsberg, MD, FACP, is an internal medicine physician who has avidly applied computers to medicine since 1986, when he first wrote medically oriented computer programs. He is in practice in Tacoma, Washington.

Other blogs of note:

American Journal of Medicine
Also known as the Green Journal, the American Journal of Medicine publishes original clinical articles of interest to physicians in internal medicine and its subspecialities, both in academia and community-based practice.

Clinical Correlations
A collaborative medical blog started by Neil Shapiro, MD, ACP Member, associate program director at New York University Medical Center's internal medicine residency program. Faculty, residents and students contribute case studies, mystery quizzes, news, commentary and more.

Interact MD
Michael Benjamin, MD, ACP member, doesn't accept industry money so he can create an independent, clinician-reviewed space on the Internet for physicians to report and comment on the medical news of the day.

PLoS Blog
The Public Library of Science's open access materials include a blog.

White Coat Rants
One of the most popular anonymous blogs written by an emergency room physician.

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