The placebo effect can be helpful to some patients
Dear Dr. Roach: In your column that ran in our local newspaper, you cautioned a reader about having positive results from a dietary change: “I need to emphasize that a diet change has a high likelihood of a placebo response — getting better because you think you should get better.”
Doctors should celebrate the fact that the mind-body connection can create a situation in which the body begins to improve/heal even when no “medicine” has been given. The medicine of hope is huge. Placebos are great because there have been no foreign chemicals put into the body that could, in themselves, cause negative responses in the body with unpleasant side effects. I would think that doctors would encourage the placebo effect in patients, especially when recommending dietary changes that are healthier for the patient.
Dear M.A.H.: As a clinician, I agree completely with everything you said. A strong belief in the effectiveness of one’s prescriptions increases the likelihood that they will be effective, whether it is a medicine, a supplement, a diet or a procedure. We don’t always know when people are getting better from the placebo effect. Another reader wrote in to tell me of research done many years ago showing how brain chemistry can be changed through the use of placebos, giving at least one mechanism by which placebos are effective. As I mentioned, the placebo response rate is around 30 percent in most studies, although there is considerable variation.
As a physician concerned for public health, I want to be sure that when I do prescribe a therapy, it is even better than placebo. I have seen enough reversals about what science thinks is healthy to be skeptical. So if I prescribe a diet — just like a medication, supplement or procedure — I would like to see evidence that it makes a difference in the condition being treated.
In the case at hand, a reader asked about diet in autoimmune disease. Some people will get better on any diet, due to the placebo response. I wanted to point out that we lack definitive proof that the Mediterranean diet is more effective than placebo at improving symptoms in autoimmune disease. However, I think the diet is safe, I agree with you that it is likely to be healthy overall and I think it is worth a try.
Email questions to ToYourGoodHealth@med.cornell.edu.