Q. I've seen many product labels that claim to boost immunity. Could they really help? Or should I be skeptical?
A. Your immune system does a remarkable job of protecting you from bacteria, viruses and other microbes that can cause disease, suffering, even death. So it seems logical to want to give your immune system a boost. But the concept of boosting immunity actually makes little sense scientifically.
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In fact, boosting your immune response is not necessarily a good thing. An overactive immune response is seen in major autoimmune diseases, such as Type 1 diabetes, rheumatoid arthritis and lupus. In autoimmune diseases, the overactive immune system starts attacking the body instead of defending it. Allergies are another example of an immune system that's overactive. A harmless little pollen gets into your nose, for example, and the immune system attacks the pollen as if it's at war.
Even if it were a good thing, attempting to boost the immune system is especially complicated. That's because the immune system is precisely that -- a system, not a single entity.
To function well, the immune system requires balance and harmony. Think of it as an army: The actions of the soldiers need to be coordinated by the generals, who determine when and where to attack, as well as when to stop attacking.
There is still much that researchers don't know about the workings and interconnectedness of the immune response. We've got to understand how the immune system works better than we currently do to achieve the goal of boosting it at just the right time and in the right part of the body.
For example, the immune system uses many different kinds of cells, which respond to different microbes in different ways. So which cells should you boost, and to what number? So far, no one knows how many or what kinds of cells the immune system needs to function at its best.
Yet many food products and packaged drinks are labeled as "supporting immunity," "boosting immunity" or providing a "defense" against germs. Most of these products just contain vitamins and minerals that people already get as part of a normal, healthy diet.
My colleague Dr. Michael Starnbach, a professor of microbiology and medical genetics at Harvard Medical School, feels strongly that when it comes to products that claim to boost immunity, there's no truth in advertising. As he says, there's simply no evidence that consuming these products will translate into better immune function. And without that evidence, the claims on food and drink packaging are just a marketing ploy -- and one that may lead us to consume more calories than we need.
It's not silly to want to find a way to help the immune system do a better job of defending us from foreign microbes, and I hope that research can teach us how to do this. However, we just don't have enough information yet to make this a reality.
• Dr. Komaroff is a physician and professor at Harvard Medical School. To send questions, go to AskDoctorK.com.