But while there are a countless number of “immune boosters” on the market — from supplements to probiotics to superfoods — few have been tested for efficacy or safety.

Doctors suggest eating a plant-based diet with lots of antioxidant-rich fruits and vegetables to support immune function. That means eating foods like blueberries, spinach, ginger, and avocados.

It’s also helpful to cut down on sugar, sugar substitutes, and processed foods, which wear down the gut and influence the body’s ability to fight infections.

Over the long term, consistent exercise creates a cascade of benefits on mood, stress, sleep, inflammation, and diseases like obesity, type 2 diabetes, and heart disease, which influence immune function.

Every day, sweat or get your heart rate up for about 30 minutes to an hour.

Chronic stress causes system-wide inflammation and increases the production of stress hormones like cortisol, which can suppress the immune system.

Meditation, exercise, and breathing exercises can help bring stress levels down.

Sleep helps the body produce vital immune cells and fight infections. It also helps the mind and body repair after stress, which in turn, benefits the immune system.