Good nutrition has always been important to good health. But can it keep you from getting sick?
Ingredients from anthocyanin to zinc, and foods from almonds to yogurt, are said to boost the human immune system. Ingestibles that supposedly keep the doctor away run the gamut from homey stuff like chicken soup and apples to exotic fare like amaranth seeds.
When it comes to health benefit claims, immunity at least has a place alongside more mainstream ones like cardiac health, digestive health and energy. But seemingly, not as prominent a one. Most companies that market immunity-boosting products do so as part of a product line with a variety of health benefits, making immunity a sort of sideline.
There are various reasons for this approach. One is that, as health benefits go, immunity tends not to be top-of-mind with many consumers.
“Consumers associate immunity with sickness,” says Shelley Balanko, senior vice president with the Hartman Group. “It’s more of a reactive health word, rather than a word that connotes proactive wellness, and that’s kind of where consumers are right now. They’re trying to be more proactive.”
Mark Stavro, senior director of marketing for Bunge North America, agrees. “Until recently, many people have given thought to immune health only after they’ve developed an illness,” he says. “As such, the general consumer hasn’t regularly been looking for food and beverage products touting immune health. However, the tides seem to be shifting toward a more proactive approach to immune health, and adding claims on packaged goods could become more popular.”
Bunge markets soybean and canola oils that are rich in omega-3 fatty acids, which are sometimes promoted as benefitting the immune system. However, they are more often touted as heart-healthy or brain-healthy. This is an example of how immunity often comes up: in tandem with other aspects of health, or with health as a whole. In other words, separating “immune system health” from health in general can be tricky.
Part of the problem is defining what “the immune system” even is. Most people associate getting sick with symptoms like runny noses, fever and lethargy. These are what doctors call the “innate response” to an invasion by bacteria or viruses: a crude, initial effort by the body to deal with the problem. The mucus in a runny nose is intended to flush out the invaders; the fever is an attempt to cook them to death, and the lethargy keeps you indoors and away from more of the bad bugs.
That’s the body’s first line of defense. The second, called the “acquired response,” involves producing antibodies that specifically target and eliminate the invading microorganisms. This is more sophisticated and effective (and is the basis for vaccines, which use dead or weakened microorganisms to elicit antibody production). But it takes five to 10 days to go into effect, which is why humans evolved the innate response: as a sort of holding action until the acquired response can get under way.
Given this set of facts, it becomes difficult to describe just what it means to “boost the immune system.” Is it treating or suppressing the symptoms of the innate response? There isn’t much that ingested nutrients can do in that regard, other than physically soothe membranes ravaged by mucus or fever. (Hot liquids do this, especially soup, which usually takes longer to consume ounce-for-ounce than hot beverages, exposing the throat and nostrils to heat longer.)
As for the acquired response, certain vitamins and minerals like zinc are indeed necessary for the production of antibodies. However, most consumers with access to a reasonably healthy diet already get all of these they need for that purpose, experts say.
Manufacturers of supplements that claim to boost immunity “might not say anything untrue, but what they are doing is implying that if someone on a normal diet takes them they will improve their immune function, which is plain wrong,” Charles Bangham, a professor of immunology and infectious diseases at Imperial College London, told The Guardian.