Nocebo and Aspartame

Dear Students,

Continuing our discussion last week of the placebo effect, is the placebo's lesser known evil twin: the nocebo effect.

Like the placebo effect, the nocebo effect is when a pill, agent or treatment that should not have any chemical, physical or mechanical effect, actually has an effect. In this case, however, it is not a positive effect based on the patients expectations, but a negative one. Some examples are listed here, and the common theme is that if a patient believed a treatment to be dangerous, it gave the feared side effect. Simply telling a patient about the side effects of a medication can increase the chances of it occurring, enough so that that the nocebo effect can possibly reverse the effect of real medication from good to bad.

The placebo effect explains, for example, explains why acupuncture can relieve headaches, and homeopathy. I have always noticed a curious argument from those that promote alternative medicine and other placebos: real medicine is harmful! It seems, although I suspect it's done unknowingly, that not only do 'alternative medicine' cheerleaders reap the benefits of the placebo effect, they also drive people away from real medicine with the nocebo effect. Since real medicine is evaluated through scientific inquiry, we know the effects of drugs and procedures and how much they do (and do not) work. It seems more than a little strange that these warnings from the alternative medicine camp dismiss out of hand scientific evidence, yet wish people to accept their claims uncritically. Propagating a fear of medicine is similar to the fear of chemicals that I have written about before (aka Chemical Free Veggies).

What prompted this weeks post was my science class's reaction to my version of "coffee" aka diet cola with lovely, lovely aspartame. Lots of people seem to think aspartame is harmful, but a quick check of reputable sources clearly proves otherwise:

A sweeping review of research studies of aspartame says there is no evidence that the non-nutritive sweetener causes cancer, neurological damage or other health problems in humans. - ScienceDaily (Sep. 15, 2007)

There is no evidence to suggest that the consumption of foods containing this sweetener, according to the provisions of the Food and Drug Regulations and as part of a well-balanced diet, would pose a health hazard to consumers. In addition, other scientific advisory bodies such as the Scientific Committee for Food of the European Community, and the Joint Expert Committee on Food Additives (JECFA) of the United Nations Food and Agriculture Organization and World Health Organization have reviewed all the available safety studies and have found aspartame to be safe. More than ninety countries world-wide, including the United States, countries of the European Union, and Australia and New Zealand, have also reviewed aspartame and found it to be safe for human consumption and allow its use in various foods. - From Food and Nutrition by Health Canada

Or just go to the Snopes page and scroll to the bottom and click and read the statements from the FDA, among all the others.

Of course, as the Health Canada website linked above states, aspartame is dangerous if you have phenylketonuria (don't worry, you'd know if you had it), but otherwise it's perfectly safe.

What does this have to do with the nocebo effect? People do report adverse effects from aspartame anecdotally (i.e. personal stories), and claim that they know aspartame is bad.

How is this resolved? From a scientific perspective, we know that aspartame is safe, insofar as we can know anything.

From Health Canada : The Safety of Sugar Substitutes

"Some people have reported sensitivities to aspartame. However, researchers have been unable to confirm these reports through clinical studies. There is ongoing research investigating this issue."

From Health Canada : Aspartame

"One study was conducted on children and adults claiming to have experienced aspartame-induced seizures. On some days they were given a placebo and on other days they were given a large single dose of aspartame. Monitoring by EEG of their brain signals demonstrated that aspartame was no more likely to cause seizures than a placebo."

But where there's smoke, why isn't there fire? If that many people report reactions, why can't we find them when we study them?

Nocebo effect.

Aspartame is an evil 'chemical', and emails such as this have been floating around for at least a decade. It is difficult to test (I suspect it would be hard to get ethical approval for studies that intend harm, even if it's just for testing a nocebo effect), but Occam's razor can serve us well here. Which is more likely? A phantom bad effect that inexplicably goes away when studied, or a nocebo effect combined with some selective thinking? If I was misinformed about aspartame to begin with, it would be not unexpected that I would attribute any bad reaction I had to any aspartame I consumed, combined with the added booster the nocebo effect gives to actually experiencing a side effect.

There is an upside, however. Given aspartame fears, it would not be unusual or unreasonable for anyone to be suspicious of aspartame. This isn't all that harmful, other than they've eliminated one method to lower their sugar intake. We don't run and check every little bit of information we come across, but if there is one area we truly need accurate and tested information, it is for our health. Whenever someone tries to inform me of their newest health fad (or even when I'm seeing a new doctor), I'll ask what they think of aspartame.

If they believe aspartame to be bad, I know that whatever fad they're trying to convince me of needs to be double-checked very carefully. Knowing truths that are easy to confirm with appropriate authorities, but very few commonly believe, is useful.

Cheers,

Ron Neufeld
Canada's Best Boarding School