Boost My Immune System? No Thanks!
Hall, Harriet, Skeptic (Altadena, CA)
Do our IMMUNE SYSTEMS NEED HELP? Walk into any health foods store or browse the Internet and you will find a multitude of diet supplements advertised to "boost your immune system" or "support immune function." Do they work? Will they keep you healthier or reduce your chances of catching infectious diseases?
A typical product is the 4Life company's "Transfer Factor" (TF), which they claim will improve your immune system by 437%. They claim it helps the immune system recognize harmful elements, changes the immune response to suit the occasion, and supports immune memory. They tell us the immune system is "incapable of responding to the challenges of everyday living."
In reality, TF has no proven value, and its use is not supported by any evidence published in peer-reviewed journals. Transfer Factor is an extract of the colostrum that precedes milk production, something that is transferred from mother to baby that helps protect the infant from infections. It consists of maternal antibodies that give the baby only temporary passive immunity to the specific antigens targeted by those antibodies. It has no effect on the baby's own immune system and its effects wear off quickly. The 437% claim is based on one study from Russia, apparently not published, showing that the natural killer cells increased by that amount, but not showing any clinical benefit to people. The company selling it is a multilevel marketing enterprise that has received warnings from the FDA, and its promotion of TF has been characterized by critics as a scare. When investigative reporter Brian Deer visited a booth selling TF and asked questions about the research behind the claims, he was ejected by security staff. (1)
As for their claim that the immune system is incapable of responding to the challenges of everyday living, didn't it evolve for just that capability? Throughout human history, hasn't it done a pretty good job of keeping us alive in the face of constant encounters with bacteria, viruses, and other threats? Why would it suddenly need help?
There are all kinds of recommendations for diet supplements that allegedly boost immune responses. There is some supporting research, but it mostly measures blood levels of immune components like IgA, lymphocytes, or cytokines. It seldom even tries to measure any meaningful clinical outcome, such as fewer colds.
We don't really know what those blood levels mean in terms of health and the ability to fight infections. We are learning that some diet supplements have mixed effects. For instance, zinc supplementation decreases the diarrhea associated with amoebic dysentery, but it also increases the incidence of A. lumbricoides, an intestinal roundworm parasite. Vitamin E supplementation increases the risk of strokes. Vitamin C supplementation may increase the risk of cataracts.
The FDA and the FTC have been cracking down on dubious "immune boosting" product claims. For instance, Andrew Weil's website was recently ordered to stop claiming that its products could help prevent swine flu and colds.
Food, Exercise, Sex, and Music
You can find all sorts of advice about how to boost your immune function with diet and lifestyle interventions. An ABC News article recommended 10 foods that boost your immunity: yogurt, turmeric, garlic, oregano, red bell peppers, green tea, pumpkins, ginger, oysters, and broccoli. Other sources have other lists, including other foods such as mushrooms. Sure, you can identify foods that contain higher amounts of antioxidants and useful nutrients that help maintain a healthy immune system as well as maintaining health in general. But are people who eat those foods healthier than people who get adequate nutrition from other foods? Probably not. If A has twice as much of a nutrient as B, you can get the same amount by eating twice as much B.
It has been claimed that a study published in the journal Chest in 2000 showed that chicken soup could increase immune response. …