In early June of this year, I wrote an article that appeared in the Huffington Post, titled "Why I won't recommend gluten free diets to my patients". To me, it was an easy recommendation to make, based on three clear facts:
1) No large scale, reproducible scientific study has ever proven non celiac gluten sensitivity to exist, nor shown any health benefits from a gluten free diet in non-celiac populations
2) Gluten-free items are significantly more expensive than traditional groceries, as much as 242 per cent more expensive in one study
3) Gluten free items are frequently higher in fat and calories than their equivalent gluten filled competitors.
Given these facts, the gluten free diet came nowhere near to meeting the high threshold a physician requires before recommending any new treatment or lifestyle change. As such, I was unprepared for the barrage of angry replies I received in response to my opinion. Various emails and online comments called me "unqualified", "insensitive", and "incompetent", along with a variety of other slurs unsuitable for publication. Through all the anger, one clear theme stood out across all the communication I received: "I feel good when I go gluten free, and reintroducing gluten makes me feel awful -- why isn't that enough for you doctors?"
It's an important question to address, especially when gluten-free is just the tip of the health fad iceberg. The reasoning that "it feels good for me, so it must be right" lies behind the prevalence of many of today's popular health trends like low carb, dairy-free, lactose-free, juice "cleanses/detoxes", and a long list of others, none of which have been validated by science or recommended by mainstream medicine, often to the chagrin of their highly invested proponents.
So "why isn't that good enough" for us in the medical profession?
Something can "feel good" while it does your body great harm
Our bodies are terrible at recognizing threats other than those that cause immediate pain or illness. Any action or chemical that stimulates the reward centres of our brains can trick us into a false sense of wellness, while at the same time causing substantial long-term damage to our health. Consider the following examples, drawn from common medical practice:
- Patients on medications for high blood pressure almost uniformly feel better when they stop taking blood pressure treatments, with resolution of side effects such as light-headedness, frequent urination, weakness, and lethargy.
- Smokers often feel quite healthy while they are regularly smoking. Smoking cessation frequently results in complaints of weight gain, anxiety, depression, and malaise. Many patients restart smoking in order to "feel better", as doing so resolves these symptoms.
- Pregnant women on thalidomide for pregnancy-induced vomiting in the late 1950s and early 1960s felt amazing, usually with complete resolution of their vomiting symptoms
- Several of my patients have sworn they feel their best when they consume multiple cans of Red Bull every day. They feel more vibrant, have better moods, and feel more mentally alert than when they abstain from this beverage.
Based on the "feel good" anecdotes above, would anyone push for physicians to recommend daily Red Bull consumption, no cessation of cigarette smoking, use of thalidomide during pregnancy, or non-compliance with blood pressure medications? Clearly not -- smoking has devastating long-term health consequences, thalidomide causes horrific birth defects, blood pressure medications have well recognized benefits for cardiovascular health and longevity that easily outweigh their side effects, and excessive Red Bull consumption has been linked to a concerning set of heart issues, including cases of sudden death. What all of these have in common (with the exception of Red Bull, which doesn't yet have good long term studies) is that it took many years of reproducible research to recognize each of these negative outcomes, and that the correct choice in every case was not the one that initially "felt good".
A sample size consisting of one person's personal experience is not adequate to extrapolate outcomes to an entire population, or to define safe treatment recommendations
A real world example, that of HIV transmission, nicely demonstrates the need for large sample sizes in medical research. The rate of HIV transmission for unprotected, receptive penile-vaginal intercourse between an HIV positive male and an uninfected woman is 8 per 10,000 exposures, or approximately 0.1 per cent. What this means is that 999 times out of 1000, a healthy woman having unprotected intercourse with an infected male partner would not contract the HIV virus. If medical doctors had based recommendations on individual anecdotes of women safely having unprotected sexual encounters with HIV positive men (which is the case 99.9 per cent of the time), we would have concluded that such behaviour does not cause disease transmission. Clearly, this would be dead wrong, and it powerfully demonstrates why physicians must base our treatment recommendations on large sample sizes, often into the thousands. Little relative weight can be given to individual accounts of safety/effectiveness.
Like many, you probably think, when it comes to experimenting with a gluten-free, or any other nutritional regime, "it's just a diet -- it can't possibly pose any real risk comparable to that posed by a deadly virus." Unfortunately this isn't the case. In 2012, a Swedish trial describing the long-term effects of a low carb diet on over 43,000 women demonstrated a 5 per cent increase in heart attack rates versus women on a standard carbohydrate diet. To put this in perspective, in 2010, the death rate among patients with a full-blown AIDS diagnosis was only 2 per cent. Dietary changes can indeed wreak serious, unanticipated deadly consequences on par with some of our most feared illnesses.
Placebo effects are very real, and very likely to account for that "feel good" sensation
Placebo effects, whereby one feels an improvement in symptoms when one believes he or she is receiving treatment, while actually receiving none, are substantial, and not to be underestimated. For example, in 1998, a study found that as much as 75 per cent of the effect of antidepressant medications was due to placebo effect, while a 2006 study found placebo treatments on average were 40 per cent successful at relieving symptoms of irritable bowel syndrome (IBS). Interestingly, a 2010 follow up study, in Paris, showed that IBS patients improved on placebo treatments even when they were aware they had been given an inert pill. The most recent study of gluten sensitivity showed that "gluten sensitive" subjects felt worse when they believed they had been switched to a gluten filled diet, even when they hadn't -- a placebo effect at work yet again. In fact, there are very few conditions in all of medicine for which placebo treatments do not offer some improvement in symptoms.
The implications of this being -- if one believes that gluten is the source of one's intestinal issues, it is very likely one will feel subjectively better when that particular agent is removed, or if one believes a given detox/cleanse will make one feel more vitality, it probably will -- if for no other reason than placebo effect. It is for this reason that modern research trials randomize subjects into two groups, one receiving active treatment and one receiving placebo, the subjects not knowing which they are receiving, to assess for effect over and above that of dummy treatments. These types of "blinded, randomized, controlled" studies do not exist to date for most of today's popular specialty diets and cleanses, and where they have been performed, have not reproducibly suggested an effect greater than that of placebo.
So next time you question why the medical profession is unwilling to endorse whatever dietary or lifestyle change has made you "feel good", remember the following. As doctors, we are bound to protect you from untested new therapies, that today's experimental, "feel good" cure may turn out to be tomorrow's next thalidomide horror story, that something as benign as a dietary change can have deadly long-term side effects, and that, best case scenario, before we recommend you empty your wallet, we need to know you are paying for more than just a placebo effect.
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