Tuesday, August 30, 2011
Is gluten-free just a fad?
There is a sizable, but still decidedly minority population that can benefit in terms of feeling better by excluding gluten, entirely or mostly, from their diets. There is a population, an order of magnitude smaller, for which it is vital to do so, and potentially even a matter of life and death. For everyone else, going gluten free is at best a fashion statement. Now, let's mill the details.
Gluten is generally described as a protein, which is basically correct. The compound is basically two proteins, gliadin and glutelin, bound together by starch (a carbohydrate). In nature, gliadin is found predominantly in the seeds of various grasses. We typically refer to the edible seeds of grasses as grains.
Grains, in turn, are made up of three parts: the bran or hull, the germ and the endosperm. Whole grains contains all three. Gluten is found in the endosperm, the principal part of the grain retained when grains are refined (and generally considered the least nutritious component). Consequently, gluten is present in grains such as wheat, rye and barley, whether or not they are "whole."
If one adopts the long view of paleoanthropology, grasses are not native human food. We don't digest the stalks per se, and the seeds of most grasses are too small to bother with. Grains therefore entered the human diet only with the advent of agriculture in the Fertile Crescent some 12,000 years ago, when their domestication led to increases in seed size. The large seeds of wheat and other edible grains familiar today are not accidental, but the product of careful nurturing by humans over millennia of the grasses nature provided.
But still, only a dozen millennia, and while that's long enough for human selection to change grains, it's not a long time for natural selection to change humans. One of the important contextual considerations when attempting to explain health effects of gluten observed today is that this really is a recently introduced nutrient, foreign to the Stone Age diet that shaped our biological adaptations.
Those health effects are ever more prominently under scrutiny.
The most significant health problem associated with gluten consumption is, technically, gluten-sensitive enteropathy, long known as celiac disease, celiac sprue or non-tropical sprue. In this condition, the immune system mounts a response to gluten as if it were a dangerous invader, such as a pathogen. The resulting inflammation damages the intestinal lining, leading to malabsorption of diverse nutrients, including both vitamins and minerals. Adverse effects can be severe, ranging from abdominal discomfort, to the manifestations of nutrient deficiencies, to an itchy rash, and over time, increased risk of intestinal cancer. Unaddressed, the condition and its complications can be lethal.
Along with celiac disease, there is also the milder "gluten sensitivity." This term is something of a catch-all, likely referring to various forms of intolerance and true allergy to gluten. The distinction between such conditions and celiac disease is that measurable antibodies to gluten are absent, as is observable damage to the lining and architecture of the intestine. Also absent is the nutrient malabsorption and increased risk of cancer. Recent insights, however, suggest the two conditions may overlap more than previously thought with regard to diverse symptoms.
There is good reason for gluten to loom large in current health lore: the numbers adversely affected by it are rising. To some extent, this is a product of something called "detection bias." The more aware and concerned the health care community is about any given health condition, the more we tend to look for it. The more one looks for any given condition, the more one tends to find it. In contrast, you don't tend to detect what you don't first consider, and for a long time, gluten sensitivity was under the proverbial radar.
Health professionals' sensitivity to gluten sensitivity accounts for some portion of the rising prevalence, but certainly not all. Studies based on blood kept in storage clearly indicate that actual rates of celiac disease have risen over recent decades, as much as four-fold in the past half a century. There is more to this story than better detection.
To my knowledge, no one knows for sure why this is happening, but there are theories. Against a backdrop of genetic vulnerability (both celiac disease and other forms of gluten sensitivity tend to run in families), there are new-age exposures to gluten that may be more likely to trigger immune system responses. In some cases, genetic modifications have increased the gluten content of wheat and other grains. It may be that genetic modifications are also introducing new nutrients into the diet, and some reactions to gluten may be primed by the company it is keeping.
There may also be an influence of nutrient combinations due to modern food processing. Gluten is a widely used texturizer. That it is found in wheat, barley, rye, triticale and possibly oat-containing products is expected. That it is found in everything from candy, to deli meats, to potato chips may be less so. Its use in all these foods is producing novel nutrient pairings, and perhaps these also function at times as an immune system trigger.
In the U.S. today, celiac disease is far from rare, affecting roughly 1% of the population at large. Gluten sensitivity affects 5 to 10 times as many. Celiac disease can be diagnosed by blood tests, biopsies or both, so you will your clinician's help. The only truly reliable test for gluten sensitivity is a trial elimination of gluten to determine if symptoms wax and wane its intake. You can do this with the help of a nutrition expert, or all on your own.
Prevalent as it is, gluten sensitivity still only affects a minority in the general population, but gluten preoccupation appears to affect many more. The potential adverse health effects of gluten in those sensitive to it have reverberated in cyberspace, creating the impression that gluten is a bona fide toxin, harmful to all. This is false; gluten is not "bad" for those tolerant of it, any more than peanuts are "bad" for people free of peanut allergy.
Also abounding are home-grown theories about health effects of gluten, including the argument that going gluten free leads to weight loss. It might, but only because avoiding gluten means avoiding a lot of foods, which in turn tends to mean reducing calorie intake. That lowering calories leads to weight loss is less than an epiphany.
Going gluten free is easier than it once was due to better food labeling, more gluten-free products and ever better guidance, in print and online. But it is still quite hard, given the widespread use of gluten in packaged foods, under a wide variety of aliases. The effort is well-justified for those who are truly gluten-sensitive, but potentially much ado about nothing for others just caught up in the trend.
In addition, the exclusion of whole grain wheat, rye, barley and potentially oats from the diet might reduce overall diet quality and fiber intake. Again, a price worth paying when gluten avoidance is clearly necessary, but cost without benefit for others.
So, as noted at the start: there is a decidedly minority but still sizable, and apparently growing, population that can benefit from excluding gluten (entirely or mostly) from their diets. There is a population an order of magnitude smaller, also growing, for which it is vital to do so, and potentially even a matter of life and death.
For everyone else, going gluten free is at best a fashion statement, and at worst an unnecessary dietary restriction that results in folly. It reflects a tendency to ingest the ever proliferating pop-culture perspectives on diet and health, without first separating the wheat from the chaff.
David L. Katz 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.
Contact ACP Internist
Send comments to ACP Internist staff at email@example.com.
- QD: News Every Day--Chocolate's good effect is als...
- Shame on you, New England Journal of Medicine
- QD: News Every Day--Half of hospitals buy gray mar...
- Great care doesn't exclude excellent bedside manne...
- Optimism, positive health and stroke risk
- QD: News Every Day--Medical news of the obvious, r...
- Talking about obesity without getting sued
- QD: News Every Day--Vaccines cause few health prob...
- Big melanoma news as FDA approves vemurafenib (Zel...
- Who pays for medical malpractice litigation?
Members of the American College of Physicians contribute posts from their own sites to ACP Internistand ACP Hospitalist. Contributors include:
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.
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
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.
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.
Toni Brayer, MD, FACP, blogs about the rapid changes in science, medicine, health and healing in the 21st century.
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.
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.
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.
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.
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.
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.
Kevin Pho, MD, ACP Member, offers one of the Web's definitive sites for influential health commentary.
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.
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.
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).
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
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)
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,
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
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.
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.
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.
The Public Library of Science's open access materials include a blog.
One of the most popular anonymous blogs written by an emergency room physician.