Red meat consumption has been linked to diabetes, cardiovascular disease, and several types of cancer (breast, colorectal, stomach, bladder, prostate, and lymphoma). There are plausible mechanisms: meat is a source of carcinogens, iron that may increase oxidative damage, and saturated fat. But correlation and plausibility are not enough to establish causation. Is red meat really dangerous? If so, how great is the risk? A couple of recent studies have tried to shed light on these questions, but they have raised more questions than they have answered.
A Systematic Review and Meta-Analysis
A new study in Circulation, “Red and Processed Meat Consumption and Risk of Incident Coronary Heart Disease, Stroke, and Diabetes Mellitus. A Systematic Review and Meta-Analysis,” by Micha, Wallace and Mozaffarian, is a systematic review of the literature. It analyzed 17 prospective cohort studies and 3 case-control studies, with a total of 1.2 million subjects. As far as I can judge, it appears to be a well-done systematic review with excellent methodology and multiple precautions. They even looked for things like publication bias (which they did not find).
They found that the consumption of processed meats, but not red meats, is associated with a higher incidence of coronary heart disease and diabetes. (Processed meats include bacon, sausage, ham, hot dogs, salami, luncheon meat and other cured meats.) The increased risk per 50 gram serving of processed meats per day was 42% for heart disease and 19% for diabetes. Unprocessed red meats were not associated with CHD and were associated with a nonsignificant trend towards higher risk of diabetes. They found no association with stroke, but this was based only on 3 studies.
Last week I wrote about the CME presentations at an obesity course put on by the American Society of Bariatric Physicians. I saved the most controversial one for last. Dr. Kendall Gerdes is a former president of the American Academy of Environmental Medicine, which I have previously written about. The AAEM is not recognized by the American Board of Medical Specialties and is categorized by Quackwatch as a questionable organization. Dr. Gerdes spoke on food allergies and food addiction.
I wasn’t convinced: I thought much of what he said was questionable. I thought, as a challenge for our readers, it might be an interesting exercise to present his information without comment and let readers look for flaws and form their own opinions. At the end, I’ll offer some suggestions of things to think about.
He described the concept of food addiction as a powerful tool to free patients from compulsive eating. Patients may “have the experience of” being addicted to foods or have symptoms of hunger and of just not feeling well. Specific symptoms of food addiction include fatigue, fibromyalgia, GI symptoms, cardiac arrhythmias, asthma, rhinitis, arthritis and seizures. There is no “gold standard” way to diagnose food allergies. He relies mainly on avoidance and challenge. (more…)
The American Society of Bariatric Physicians recently invited me to speak at their continuing medical education (CME) conference on obesity in Seattle. They got my name from Stephen Barrett of Quackwatch and asked if I could speak about questionable weight loss treatments like HGH, MIC (methionine, inositol and choline), and the HCG Diet. I seized the opportunity to discuss how to evaluate any medical claim, with examples from alternative medicine as well as from weight loss. My title was “Questionable Evidence for Questionable Treatments.” I talked about some of the things that can go wrong in clinical trials and why simply finding reports of positive randomized controlled trials (RCT) is not enough. I advocated rigorously science-based medicine and recommended the SBM website.
Several people came up afterwards to express their thanks and their agreement, but some of the questions from the audience were rather hostile. One man said he was a military doctor and he was using and teaching acupuncture (which I had criticized as a bad example of “tooth fairy science” in my talk). I asked for his opinion of battlefield acupuncture and he just said “No comment.” A couple of people thought science wasn’t enough and thought it was okay to prescribe questionable treatments when there was no proven effective treatment. I responded that I had no objection as long as the patient was told the facts and not given the false impression that the questionable treatment had been tested and shown to work.
I was glad for the chance to meet some of the ASBP members. I had never met a bariatric physician and was interested to learn about their practices and philosophies. I had never really thought about the fact that most obese patients had associated diseases like hypertension and diabetes, so their overall management could be very complex. I attended the whole obesity course: some of what I heard was educational, some of it was questionable, and some of it was frankly disturbing. (more…)
An article entitled “The Burden of Suboptimal Breastfeeding in the United States: A Pediatric Cost Analysis,” by Bartick and Reinhold, was published in Pediatrics 2010 April 5. According to this news report, it showed that 900 babies’ lives and billions of dollars could be saved every year in the U.S. if we could get 90% of mothers to breastfeed for at least 6 months. It says breastfeeding has been shown to reduce the risk of stomach viruses, ear infections, asthma, juvenile diabetes, Sudden Infant Death Syndrome and even childhood leukemia.
This new study did not provide any new evidence. It simply took risk ratios from a three year old government report, extrapolated, and estimated the costs.
I get all sorts of mail. I get mail from whining Scientologists, suffering patients, angry quacks—and I get lots of promotional material. I get letters from publishers wanting me to review books, letters from pseudo-bloggers wanting me to plug their advertiblog—really, just about anything you can imagine.
Most of the time I just hit “delete”; it’s obvious that they’ve never read my blog and they’re just casting a wide net for some link love. But a recent email from a PR firm piqued my interest: (it’s a long letter, and I won’t be offended if you simply reference it rather than read the whole thing now):
March 4, 2010
Today I went to the one-day, 2nd Yale Research Symposium on Complementary and Integrative Medicine. Many of you will recall that the first version of this conference occurred in April, 2008. According to Yale’s Continuing Medical Education website, the first conference “featured presentations from experts in CAM/IM from Yale and other leading medical institutions and drew national and international attention.” That is true: some of the national attention can be reviewed here, here, here, and here; the international attention is here. (Sorry about the flippancy; it was irresistible)
I’ve not been to a conference promising similar content since about 2001, and in general I’ve no particular wish to do so. This one was different: Steve Novella, in his day job a Yale neurologist, had been invited to be part of a Moderated Discussion on Evidence and Plausibility in the Context of CAM Research and Clinical Practice. This was not to be missed.
BACKGROUND: A BAD, BAD LAW
One of the themes of this blog has been how, over the last couple of decades, the law has been coopted by forces supporting “complementary and alternative” medicine (CAM) in order to lend legitimacy to unscientific and even pseudoscientific medical nonsense. Whether it be $120 million a year being spent for the National Center for Complementary and Alternative Medicine (NCCAM) or attempts to insert provisions mandating that insurers in the government health care co-ops that would have been created by President Obama’s recent health care reform initiative (which at the moment seems to be pining for the fjords, so to speak), the forces who do not want pesky things like regulation to interfere with their selling of pseudoscience have been very successful. Arguably the crown jewel of their legislative victories came in 1994, when the Dietary Supplement Health and Education Act (DSHEA) was passed. Demonstrating that pseudoscience is a bipartisan affair, the DSHEA was passed, thanks to a big push from the man who is arguably the most powerful supporter of quackery in government and the man most responsible for the creation of the abomination that is NCCAM, Senator Tom Harkin (D-IA), along with his partner in woo, Senator Orrin Hatch (R-UT). It should be noted that Harkin happens to be the recipient of large contributions from supplement manufacturer Herbalife, demonstrating that big pharma isn’t the only industry that can buy legislation related to health.
Dr. Lipson has discussed the DSHEA before (calling it, in his own inimitable fashion, a “travesty of a mockery of a sham“) as has a certain friend of mine. Suffice it to say that the DSHEA of 1994 is a very bad law. One thing it does is to make a distinction between food and medicine. While on its surface this is a reasonable distinction (after all, it wouldn’t make a lot of sense to hold food to the same sorts of standards to which drugs are held), as implemented by the DSHEA this distinction has a pernicious effect in that it allows manufacturers to label all sorts of botanicals, many of which with pharmacological activity, as “supplements,” and supplements, being defined as food and not medicine, do not require prior approval by the FDA before marketing:
As a mother, I am a passionate advocate of breastfeeding and I breastfed my four children. As a clinician, though, I need to be mindful not to counsel patients based on my personal preferences, but rather based on the scientific evidence. While breastfeeding has indisputable advantages, the medical advantages are quite small. Many current efforts to promote breastfeeding, while well meaning, overstate the benefits of breastfeeding and distorts the risks of not breastfeeding, particularly in regard to longterm benefits.
As Joan Wolf explains in an article entitled Is Breast Really Best? Risk and Total Motherhood in the National Breastfeeding Awareness Campaign:
… Medical journals are replete with contradictory conclusions about the impact of breast-feeding: for every study linking it to better health, another finds it to be irrelevant, weakly significant, or inextricably tied to other unmeasured or unmeasurable factors. While many of these investigations describe a correlation between breast-feeding and more desirable outcomes, the notion that breast-feeding itself contributes to better health is far less certain, and this is a crucial distinction that breast-feeding proponents have consistently elided. If current research is a weak justification for public health recommendations, it is all the more so for a risk-based message that generates and then profits from the anxieties of soon-to-be and new mothers…
Wolf describes the problems with many studies of breastfeeding, particularly those that focus on long term outcomes:
In breast-feeding studies, potential confounding makes it difficult to isolate the protective powers of breast milk itself or to rule out the possibility that something associated with breast-feeding is responsible for the benefits attributed to breast milk. As the number of years between breastfeeding and the measured health outcome grows, so too does the list of possibly influential factors, which means that the challenge is magnifiedwhen trying to evaluate long-term benefits of breastfeeding… Breast-feeding, in other words, cannot be distinguished from the decision to breast-feed, which, irrespective of socioeconomic status or education,could represent an orientation toward parenting that is itself likely to have a positive impact on children’s health. In instances such as this, in which the exposure (breast-feeding) and confounder (behavior) are likely to be very highly correlated, confounding is especially difficult to detect. When behavior associated with breast-feeding has the potential to explain much of the statistical advantage attributed to breast milk, the scientific claim that breast-feeding confers health benefits … needs to be reexamined.
The New York Times has been periodically running a series about the “40 years’ war” on cancer, with most articles by Gina Kolata. I’ve touched on this series before, liking some parts of it, while others not so much. In particular, I criticized an article one article that I thought to be so misguided about how the NIH grant system leads researchers to “play it safe” and how we could cure cancer if we could just fund “riskier” research that I had to write an extended screed about the misconceptions in the article. The latest installment, Medicines to Deter Some Cancers Are Not Taken, also by Kolata, is much better in that it discusses a problem at the heart of cancer, namely that we have developed drugs that can decrease the risk of specific cancers but they are not as widely used as they could be.
The first part of the article contrasts a seeming incongruity:
Many Americans do not think twice about taking medicines to prevent heart disease and stroke. But cancer is different. Much of what Americans do in the name of warding off cancer has not been shown to matter, and some things are actually harmful. Yet the few medicines proved to deter cancer are widely ignored.
Take prostate cancer, the second-most commonly diagnosed cancer in the United States, surpassed only by easily treated skin cancers. More than 192,000 cases of it will be diagnosed this year, and more than 27,000 men will die from it.
And, it turns out, there is a way to prevent many cases of prostate cancer. A large and rigorous study found that a generic drug, finasteride, costing about $2 a day, could prevent as many as 50,000 cases each year. Another study found that finasteride’s close cousin, dutasteride, about $3.50 a day, has the same effect.
This is indeed a contrast. Think about it. Millions of Americans take statins, for instance, to lower their cholesterol and thereby try to prevent the complications of elevated cholesterol, such as heart disease, vascular disease, and strokes. Yet, for at least two common cancers, there are proven effective drugs that will lower the risk of cancer considerably with a side effect profile at least as favorable as that of statins.
EDITOR’S NOTE: Dr. Gorski is currently in Chicago attending the American College of Surgeons Clinical Congress. As a result, he has not prepared a post for this week (although he doesn’t feel too guilty about missing this week, given that he did write two rather hefty posts last week, one on the cancer quackery known as the German New Medicine and the other on a rather dubious monkey study being promoted by the anti-vaccine movement). Fortunately, we have Ben Kavoussi to fill in with a post on some of the more exaggerated claims of advocates of nutritional interventions for various diseases and conditions. Enjoy!
- A centipede was happy quite,
- Until a frog in fun
- Said, “Pray, which leg comes after which?”
- This raised her mind to such a pitch,
- She lay distracted in the ditch
- Considering how to run.
Just like complementary and alternative medicine (CAM), nutritionism — meaning the unexamined assumption that food is only a conveyor of the substances it contains 1,2 — has evolved independently of science and medicine since the 1970s, and has caused so much wondering and confusion about food and diet that many Americans have become unable to eat properly. Today, there isn’t a popular magazine that doesn’t have a “health and nutrition” section that — often with the backing of very little science — promises many health benefits of a nutrient or warns against the harms of another; and then provides a list of foods that contain it. The same publication might time and again write the exact opposite, further adding to the already-prevalent nutritional confusion. Nutritionism is thus an ideology sourced by popular beliefs, academic reveries, and the food and dietary supplements industry, where food is simply seen as a mean to achieve a specific health goal. In its latest form, however, coupled with genomics and biomedical informatics, and called “nutrigenomics” or “nutritional genomics,” nutritionism takes academic reveries to such an extent that it could be accurately described as “science fiction.” The Center of Excellence for Nutritional Genomics at UC Davis writes indeed (in bold) on its website that:
“The promise of nutritional genomics is personalized medicine and health based upon an understanding of our nutritional needs, nutritional and health status, and our genotype. Nutrigenomics will also have impacts on society — from medicine to agricultural and dietary practices to social and public policies — and its applications are likely to exceed that of even the human genome project. Chronic diseases (and some types of cancer) may be preventable, or at least delayed, by balanced, sensible diets. Knowledge gained from comparing diet/gene interactions in different populations may provide information needed to address the larger problem of global malnutrition and disease.”