When you're laid up with the aches, pains, and coughs of the flu, the last thing you probably feel like doing is eating. But your body needs fuel to keep it going while your immune system fights off the infection. And what you feed it can boost that effort — or leave you feeling a little worse. Here's what to eat when you're sick with the flu.

There's a Reason Your Mother Made You Chicken Soup

The recommendation to eat chicken soup goes back much further than your mother or grandmother. In fact, it was an Egyptian Jewish philosopher-physician named Moshe ben Maimonides who first recommended chicken soup for respiratory tract illnesses in the 12th century.

Research nine centuries later is shedding new light on the science behind eating chicken soup when you have a cold or the flu. Chicken soup with vegetables appeared to have a mild anti-inflammatory effect in at least one study. An often-cited study published four decades ago found that chicken soup seems to loosen up mucus and improve respiratory symptoms. But a lot of unanswered questions remain.

Drink Plenty of Fluids — and Some Green Tea

When fighting a fever, it's more important than ever to stay hydrated. Drinking water, broth, and other fluids will help keep your body hydrated. If your stomach can tolerate it, it's fine to have a cup or two of coffee. Contrary to popular belief, normal coffee consumption does not contribute to dehydration. (Alcohol, on the other hand, is dehydrating and should be avoided.)

While coffee is acceptable, it's even better to brew a cup of tea. A study in 2018 reviewed existing research on catechins, an antioxidant compound found in tea, especially green tea. The researchers found some evidence that green tea catechins reduce cold and flu symptoms.

Foods Rich in Vitamin D

Vitamin D is a bit of a mystery nutrient. Scientists understand a good amount about its importance to the body. However, they have a lot more to learn about what vitamin D can and can't do. Scientists also still aren't sure whether supplements are as beneficial as getting vitamin D from your diet and the sun.

But there's enough evidence to suggest vitamin D does have anti-inflammatory effects and may boost the immune system's ability to fight the flu. The food with the most vitamin D is fatty fish, such as tuna and salmon. Dairy products, such as milk and cheese, and eggs, also contain some vitamin D. Other foods, such as orange juice, soy milk, and some cereals, may be fortified with it.

Fruits and Vegetables

It's no surprise that what's good for you when you're sick is the same as when you're healthy. Flavonoids (found in citrus) and antioxidants (found in a wide range of fruits and vegetables) may help support the immune system.

Foods rich with antioxidants include berries, beans, beets, and leafy greens (and yes, a bit of dark chocolate). You can also get the antioxidant glutathione, which appears to help fight infections, from these foods:

  • Tomatoes
  • Almonds
  • Walnuts
  • Cabbage
  • Avocados
  • Garlic
  • Cucumber
  • Broccoli
  • Spinach
  • Asparagus
  • Brussels sprouts

Foods That Are Easy to Digest

Any food that makes your digestive system work harder to break it down is taking away precious energy from the rest of your body when you're sick. That means avoiding greasy or fried foods and any foods high in saturated fat. These can all take a toll on your gastrointestinal system. Instead go for simple carbohydrates that take it easy on your body, such as crackers, toast, and light noodles.