You Can’t ‘Boost’ Your Immune System. Do This Instead

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Each year, supplement brands fall over themselves to sell us products with the (asterisked) promise that they will boost immunity and provide protection through cold and flu season. (The asterisk, literally speaking, being that none of these claims have been evaluated by the FDA.) But what does it actually mean to boost the immune system? The short answer: nothing.

“That’s a pseudoscience term,” says Laura Purdy, MD, MBA, founder and CEO of Swell Medical. “You’re not boosting anything. You’re not giving yourself more B cells or more T cells.”

First of all, instead of thinking of immunity as something that can be boosted beyond its normal capacity, think of it like any other system in your body; you simply want it to work the way it’s supposed to. “I like the word ‘optimize’ better than ‘boost,’” says Dr. Purdy.

Second, similar to how you can’t target belly fat specifically, we can’t isolate our immunity, because the immune system isn’t just one thing. “The immune system is a highly complex network, involving components like the spleen, white blood cells, the lymphatic system, the gut microbiome, and even our skin. And these systems all work together,” says nutritionist Daryl Gioffre, DC. In other words, to optimize your immune system is to optimize your overall health, and vice-versa. It’s not a slogan that’s going to send vitamins flying off the shelf, but that’s just how the immune system works.

So what’s the most effective way to optimize your immune system, and what else have we been getting wrong about cold and flu season? Here’s what you need to know.

Vitamin C supplements are almost certainly doing nothing for you

Let’s cut straight to it: Supplementing with specific vitamins and minerals has not been validated by scientific research to improve immunity. That’s just a fact. “If you look at large-scale studies, there really aren’t any that prove if you take high doses of vitamin C or zinc you’re not going to get sick,” says Dr. Purdy. “The studies are inconclusive. There’s not enough evidence out there.”

One of the reasons why large-scale studies are inconclusive is that while most people do not experience any benefits, there are outliers. “If you’re eating a healthy diet, adding vitamin C is not going to do a whole lot,” says Karen Duus, PhD, professor of microbiology and immunology at Touro University Nevada. However, for people with specific documented nutrient deficiencies, supplementing can help pick up the slack. “There are certain supplements that have proven effects when there’s a deficiency,” says Ernst von Schwarz MD, PhD, clinical professor of medicine at UCLA.