How are you faring during this cold and flu season? The answer depends, at least in part, on how your body’s immune system is protecting you from the many viral and bacterial illnesses that gets passed around every winter.
A strong immune system is crucial to our ability to fight off potential illness-causing pathogens, and there are several ways in which the body fortifies its defenses. “Innate immunity is what we’re born with, and includes the normal barriers that we have, such as our skin or the lining of our digestive tract, and even some of the secretions in our sinuses and airways that help protect us and keep bacteria and viruses out,” says Washington University Clinical Associate Dr. Matthew Bonzelet, a physician specializing in internal medicine with Maryland Medical Group. “We also have some cells and proteins that are our first responders to infections. They’re called to sites where we’ve had (bacterial or viral) invaders to set up our first line of defense and to call upon more specialized defense cells to come and lend a hand,” Bonzelet adds.
Acquired immunity develops through exposure to specific pathogens. This is the type of immunity built through vaccinations, such as the flu vaccine, which exposes the body to the same antigens or parts of antigens that cause disease. While the antigens delivered via vaccine are not strong enough to cause the actual disease, they do stimulate the immune system to produce antibodies against them.
A third type of immunity, passive immunity, develops through antibodies passed from mother to child during pregnancy and via breastfeeding. This type of immunity helps babies defend against illness in the first months of life.
Besides what we’re born with and what we can achieve via vaccines, maintaining a strong immune system is largely a matter of good self-care. “The best thing to do is stay as healthy as you can,” says Dr. Sarah George, associate professor of infectious diseases at Saint Louis University. “Eat a good, balanced diet with plenty of fruits and vegetables, exercise regularly, keep within a normal body weight, and get good sleep. It’s been reasonably well shown that people who are not getting enough sleep, who are extremely fatigued or extremely overweight have weaker immune systems and are more prone to infection.”
George notes that the mechanisms around these findings have not been thoroughly explained, but studies indicate that children who eat a diet containing a lot of fast or processed food and sugar experience more respiratory infections.
Over-the-counter immunity boosters crowd drugstore shelves, but Bonzelet and George agree that little to no real evidence exists to support manufacturer claims. “We do know that a lot of the substances that are in these products, like vitamin C and zinc, are important in the role of the immune system, but we haven’t seen that people who have normal levels of vitamin C and zinc have any benefit by increasing the amount that they have,” Bonzelet says. He adds that some studies have been touted to support claims that products shorten the duration of a cold or help prevent the common cold. “But when these studies are looked at more closely, they’re not great studies,” he explains. “The jury’s out. We’re not convinced that this works well.”
Although George is “dubious” about over-the-counter immune-boosters, she has a final word of advice: “Get your flu shot, please. It’s still effective and available, so if you haven’t had it, please get it.”