Apples are a rich source of phytochemicals—like quercetin, which is known for its antioxidant and anti-inflammatory effects that help with regulating immune responses.
Here's the gist of how it works. Free radicals not only damage your cells but also activate genes that trigger an increased inflammatory response.
Red apples, in particular, seem to be high in this flavonoid. Also, don't peel your apples or you'll miss out on this health benefit—because quercetin is exclusively found in the skin.
Quercetin isn't the only antioxidant that apples contain. They also boast a number of other flavonoids, like catechin, epicatechin, procyanidin, phloridzin, coumaric acid, chlorogenic acid, and gallic acid, which have inflammatory and immune system benefits.
In fact, when compared to other popular fruits, apples had the second-highest level of antioxidant activity and the highest proportion of free phenolics.
Apples can help to support gut health because they provide a specific type of soluble fiber called pectin. One 2010 study found that when women consumed two apples a day, they increased the good bacteria in their guts after just two weeks.
It's no secret that vitamin C is one of your body's best defenses when it comes to warding off pesky colds and other illnesses. What you may not realize, however, is that it plays many different roles in boosting your immune system.
Studies have shown that by simply consuming more vitamin C, you can increase the levels of antioxidants in your blood by a whopping 30%—and in turn, this can help your body's defenses to keep inflammation at bay.
In fact, mice who were fed soluble fiber only got half as sick as the other group, and recovered 50% sooner, after scientists induced illness in all of them.