Skip to content

Surprising Side Effects Oatmeal Has On Your Immune System, Says Science

That breakfast bowl really can do a lot for your body!
FACT CHECKED BY Kiersten Hickman

Did you know your diet plays a critical role in maintaining a healthy, well-functioning immune system? Some foods pack a particularly powerful combination of nutrients that play a part in immune health—and oatmeal happens to be one of them. Not only are oats incredibly rich in cholesterol-lowering fiber, high-quality protein, but they also contain a wide range of essential minerals and other compounds with a high level of antioxidant activity. Need another excuse to dig into a hearty bowl of oats? Below, we've rounded up all the surprising side effects oatmeal can impact your immune system—based on scientific sources and studies. And for even more healthy eating tips, be sure to check out our list of 22 Meals to Melt Belly Fat in 2022.

The beta-glucans may increase your immune response to certain infections.

savory oatmeal

You probably know oats are an excellent source of fiber—but what you may not know is that the particular kind of fiber they contain, called beta-glucans, can help to support immune health. The body doesn't produce beta glucans naturally, which means the only way to get these beneficial compounds is through supplements or your food (namely whole grains).

Here's how they work: Beta-glucans are a form of soluble fiber that moves slowly through the digestive tract, "catching" cholesterol as it goes. They also boast antioxidant and antimicrobial capabilities that have an immune-strengthening effect and are known to stimulate white blood cells, which play a crucial role in protecting the body from infectious diseases.

Preliminary research is already examining whether beta-glucans could help protect you from COVID-19. But a 2003 study showed that beta-glucans extracted from oats can enhance resistance to infections from Staphylococcus aureus (a bacteria known to cause skin infections, pneumonia, heart valve infections, and bone infections) and Eimeria vermiform.

By the way, soluble fiber helps to feed the "good" bacteria living in your gut—and a healthier, more balanced microbiome is critical to supporting the body's immune function. And a 2017 study conducted by Tufts University researchers revealed that adults who consumed a diet rich in whole grains (like oats) showed modest improvements in their microbiome as well as certain immune responses.

Pro tip: next time you're at the grocery store, make sure to reach for steel-cut oats, which contain significantly more fiber than the rolled, quick-cooking kind. Here's why steel-cut oats are considered The #1 Best Oatmeal to Eat, According to a Dietitian.

It can make your immune system more efficient overall.

bowl of oatmeal with nut butter fruit and chocolate chips

Speaking of beta-glucans, they actually act as immunomodulatory agents, which means they trigger a series of events that can help the immune system to function more efficiently.

How do they do this? By fueling the activity of macrophages, immune cells that destroy pathogens. Macrophages also release cytokines, chemicals that allow immune cells to communicate with one another, thus making them more powerful in protecting you from infection. Pretty cool, huh?

Here are 7 Ways to Make Oatmeal for a Flat Belly.

The arginine can boost the activity of T cells.

peanut butter oatmeal

Oats have a high concentration of arginine, an amino acid that not only helps to regulate blood flow, heal injuries, and remove waste via the kidneys but also boosts the immune system. The way it accomplishes this, according to a 2016 study, is by increasing the activity of a particular type of immune cells called T cells. Basically, when there are higher levels of L-arginine in your system, the T cells survive longer and are thus more effective. Since T cells can identify and kill off cancer cells, that's a promising indication that beta-glucan may help to inhibit the spread of cancer.

Get even more healthy tips straight to your inbox by signing up for our newsletter!

The selenium lowers oxidative stress while enhancing immunity.

oatmeal honey

Your body only needs a very small amount of selenium to function properly—however, even in trace doses, this mineral provides some pretty amazing health benefits. In addition to helping regulate the immune response, selenium can also shield your body from oxidative damage, infection, and chronic disease.

The National Institutes of Health recommends that adults get about 55 micrograms of selenium per day. Fortunately, 1 cup of oats offers 13 micrograms—or 24% of your RDA.

What makes selenium so beneficial is that it binds with proteins to form selenoproteins, which can act as antioxidants to protect your cells from damage caused by free radicals.

The zinc aids your body in fighting off foreign invaders.


Zinc has a profound influence on your immune system. Luckily, oatmeal is one of the top foods highest in zinc, with 2 micrograms—or 21% of your recommended daily value per cup.

Even a mild zinc deficiency can impede immune system function. In fact, research has shown that there's a link between low levels of zinc and increased susceptibility to pneumonia and other infections specifically in children and older people.

Zinc also plays an essential role in creating and activating T-lymphocytes, one of the major components of the immune system.

The iron protects your immune system from vulnerability.

peanut butter oatmeal

The recommended daily intake for iron—which plays a key role in many bodily functions—is about 18 micrograms per day. However, it can be difficult for many people, especially vegans and vegetarians, to meet this requirement. Here's the problem with that: when your body doesn't have enough iron, your immune system is more vulnerable to invading bacteria. Not only that, but iron is essential for the normal development of cells that kill pathogens.

The good news is that 1 cup of oats packs 3.4 micrograms of iron, or 19% of the RDI.

It contains a special kind of antioxidant that can strengthen your immune system.


Did you know that oats are literally the only food known to have avenanthramides, a particular type of antioxidants? According to a 2019 study, this particular group of phenolic compounds shows promising results in fighting off cancer. While more research is needed to explore the potential of this specific effect, avenanthramides are known to suppress inflammatory responses while stimulating immune functions.

Not sure which oatmeal to buy? We Tasted 7 Oatmeals, and This Is the Best One!

Rebecca Strong
Rebecca Strong is a Boston-based freelance health/wellness, lifestyle, and travel writer. Read more about Rebecca
Filed Under