Tag Archives: New England Journal of Medicine

MSG and gluten intolerance: Is the nocebo effect to blame?

Gluten and MSG intolerance may be only in your head.
That’s nothing to be ashamed of.

By via Slate Magazine

msg noWhile living in China from 2003 to 2005, I often served as the designated translator for fellow expatriates. Whenever we ate out, this involved asking our server which menu items contained MSG. Invariably I was told that almost everything is made with weijing (“flavor essence”), including, on one occasion, the roast peanut appetizer my MSG-sensitive friends were snacking on as I made my inquiry.

After observing that no one reacted to the peanuts, I was inspired to conduct a simple (and admittedly unethical) experiment. One evening, instead of translating honestly, I told my companions at a large banquet that the kitchen had promised to avoid using MSG. Everyone thanked me and happily ate their meal, dish after poisoned dish.

An hour later? Two hours later? The next day? Nothing.

I repeated this experiment on multiple occasions, always with the same result. And yet foreigners living in China routinely complained of reactions to their food that included headaches, chest pain, and shortness of breath. Was there something about my presence that conferred temporary resistance to MSG? Or could it be that MSG sensitivity was only in their heads?

In April 1968, the New England Journal of Medicine published a letter by Robert Ho Man Kwok that described a strange set of symptoms: “Numbness at the back of the neck, gradually radiating to both arms and the back, general weakness and palpitation.” Stranger still was the fact that Dr. Kwok, himself a Chinese immigrant, typically noted the onset of these symptoms 20 minutes after eating at restaurants serving “Northern Chinese food.”

An editor at NEJM titled Kwok’s letter “Chinese-restaurant syndrome,” and thus began a minor epidemic. For countless sufferers, a mystery had been finally solved. “NO MSG” signs sprang up across the United States, and, eventually, the world. Study upon study confirmed the syndrome’s existence and speculated about the science underlying it.

But after reading some of these studies, even a layperson will start to get suspicious. Take the editorial note that precedes Russell S. Asnes’ article “Chinese Restaurant Syndrome in an Infant”:

“The evidence that this infant had the Chinese Restaurant syndrome may be only circumstantial. However, the description of the symptom is accurate as attested to by the Editor’s wife who suffers from the same malady. Incidentally, she remains a devotee of Chinese cuisine.”

Science, that sworn enemy of circumstantial evidence, marched on, and slowly but surely physiological explanations of Chinese restaurant syndrome began to lose credibility. Double-blinded studies failed to turn up evidence of a clinical condition. MSG, many people noted, appears in everything from sushi to Doritos. gluten-intolerantJournalists performed experiments similar to mine, their results echoing the consensus of professional scientists: In the overwhelming majority of cases, MSG sensitivity is a psychological phenomenon.

Despite this thorough debunking, a surprisingly large number of people—generally those who lived through the epidemic—still insist they are sensitive to MSG. Google around and you’ll turn up scores of alarmist websites, which tend to combine outdated research with anecdotal, indignant rebuttals of the current scientific wisdom: “How dare you suggest my MSG sensitivity is only in my head? Why, just the other day I went out for Chinese and forgot to ask about MSG. After 45 minutes I couldn’t breathe and my heart was racing.”

Occasionally, as with vaccines and climate change denial, alarmism veers into paranoia, yielding accusations that a shadowy East Asian cabal is paying off scientists and journalists to regurgitate their propaganda.

MORE . . .

“Small Study of Reflexology Finds Nothing,” Headline Should Read

Written by Kyle Hill via randi.org

If alternative medicine wants to be taken more seriously, the studies must be better designed and be put in the proper context.

UK’s The Telegraph reported last month that a study published in the journal Complimentary Therapies in Clinical Practice showed that reflexology was “as effective as pain killers.” It’s a bold claim.

However, this claim is backed up by nothing in the study. In fact, all the methodological flaws encourage a reflexive rejection of the study’s conclusions.

No Control, No Power

Reflexology is based on the unsubstantiated belief that each part of each foot is a mirror site for a part of the body. (source: The Skeptic’s Dictionary)

You don’t have to be a scientist to know what questions to ask about a study. Some of the most basic are “What was the sample size?” and “Was it double-blinded?” Even these basic questions can tell you a lot about what researchers find.

The reflexology study had a sample of 15 participants, most of them women, and each received both experimental conditions (we will come back to this point later on). If 15 sounds like a small number to you, that’s because it is. In fact, because the statistical analyses they were using looked at group averages, this small number gets broken down even further. With so few participants, this study does not have the power to comment on very much. In larger studies, vexing variations between individuals “cancel out” to hit on some average value. Whether this study hit on something interesting or not, we wouldn’t be able to tell—values are lost in the large variations between so few people.

To control for possible placebo effects, the researchers used transcutaneous electrical nerve stimulation (TENS) as the “sugar pill” comparison to reflexology.

Transcutaneous electrical nerve stimulation (TENS) device placed on the wrist.

Transcutaneous electrical nerve stimulation (TENS) device placed on the wrist.

But the famous “sugar pill” experimental design comes from the idea that subjects should not be able to tell the difference between one pill and another. In this study, every subject could easily tell the difference between a massage of the foot and some electrodes placed on the wrist. And this brings in other problems. Because each subject, and each researcher, knew what treatments were given, there was effectively no blinding. Blinding is the best way to avoid the pernicious biases that tend to creep into studies like this. Needless to say, an unblinded study is far less persuasive.

And what of the TENS treatment that was supposed to act as a placebo? One systematic review concluded that there is “no benefit of TENS compared with placebo.” Another review found that “evidence for the efficacy of…is limited and inconsistent,” in regards to treating chronic back pain. The New England Journal of Medicine concluded that “treatment with TENS is no more effective than treatment with a placebo, and TENS adds no apparent benefit to that of exercise alone,” also referring to treating chronic back pain.

So, according to much larger studies, there is no reason to believe that TENS does much for pain. TENS could then effectively be a placebo, but the authors of the reflexology study . . .

MORE . . .

%d bloggers like this: