As Always..You’ve probably heard by now – or perhaps you know first-hand – this year’s flu season is one of the worst. And it’s expected to be weeks or even months before we’re in the clear.

More than an inconvenience, the flu can be life-threatening. So, it’s especially important to do all you can to keep your immune system battle-ready this season. A healthy diet and lifestyle play a big part – nutrients like iron, zinc and selenium and plant-based flavonoids are essential for a strong immune system.

Here are four foods that can help fortify your defenses:

Tea: Tea is among the richest sources of antioxidant flavonoids that have been shown to boost the immune system. One study found that compounds in tea prime the immune system to attack invading bacteria, viruses and fungi. Choose black, green or oolong for the most benefits.

Spices: Herbs and spices are some of the most concentrated sources of antioxidants of all foods, and many of these plant powerhouses are known to provide antiviral, anti-inflammatory, and immune-boosting properties too. Look for more ways to add herbs and spices into your favorite foods and beverages.

Blueberries: Research shows that blueberries have the highest levels of disease-fighting antioxidants of all commonly consumed fruit. These tiny berries also contain quercetin, a flavonoid that acts like an antihistamine and anti-inflammatory, and may protect against heart disease and cancer. Researchers speculate that quercetin’s antihistamine effect may also help to reduce symptoms associated with allergies, including a runny nose and watery eyes. No fresh blueberries at your local market? Pick frozen as they’re nutritionally comparable to fresh. Sprinkle some blues on your yogurt, blend into a smoothie, or enjoy them straight from the fridge!

Yogurt: Yogurt contains live and active cultures, which replenish our immune system with healthy bacteria. What’s more, having just 1 cup of calcium-rich yogurt provides nearly 20% of the adult daily requirement for zinc, an essential mineral for healthy immune function. Start your morning with a cup of yogurt or try some of these delicious ways to enjoy yogurt for snacks or dessert.

Along with eating right, make sure you’re getting adequate sleep. The immune system and body repairs and recovers during sleep, so strive to get as much as you can. The recommendations are for at least 7 hours a night, but 8-9 is even better.