My daughter just spent two weeks recovering from COVID-19. And she doesn’t want to do that again. She did, however, request that I write something about foods that help strengthen the immune system.

Glad to, my dear. After all, experts tell us that a strong immune system is one of the strongest weapons we have against viral illnesses like influenza (flu) and COVID-19. And our food choices help determine the strength of that system.

According to a 2020 article on this topic in Nutrition Reviews, certain components in our diet “contribute substantially to a robust immune system.” And many of these substances work in unison to enhance our body’s ability to resist infections such as COVID or the flu. Here are some of the top contenders:

Protein is the backbone of our body’s defense mechanism since antibodies and other immune cells are made of this essential nutrient. Aim to include a protein-rich food such as eggs, fish, poultry, meat, dairy and soy foods with each meal. High quality protein can also be found in combinations of vegetables, whole grains, legumes, beans, lentils and nuts.

Vitamin A strengthens and regulates one of the most important immune organs of the body — the skin. And that includes our digestive tract and lungs. Think bright orange, reds and greens when you’re looking for vitamin A-containing foods: sweet potatoes, carrots, kale, spinach, red peppers, apricots and eggs (yolk).

Vitamin C is a potent immune booster. And we need it every day in foods such as citrus fruits, tomatoes, peppers, broccoli, kiwifruit and strawberries.

Vitamin D has the ability to guard against respiratory infections, including pneumonia, say researchers. In addition to a little sunlight, salmon and other dark-fleshed fish provide this vitamin. So do vitamin D-enriched milk and soy beverages.

Zinc is a powerhouse immune booster, involved in more than 300 reactions that help protect our bodies from harmful invaders. Oysters, beef and fortified breakfast cereals are the most potent sources of this nutrient.

Vitamin E works with vitamin C to help healthy cells resist unwelcome guests. Vitamin E generally resides in whole grains or fortified cereals, seeds (such as sunflower seeds), nuts and vegetable oils.

Probiotics — the good bacteria we find in cultured foods such as yogurt and kefir and also in supplements — help the body produce more antibodies to stimulate its ability to fight off unwelcome viruses, say researchers. And we feed these beneficial bacteria when we eat high fiber foods such as vegetables, fruit, whole grains, beans and nuts.

Kind of sounds like the old familiar balanced diet with a variety of foods, yes?

Oh, and don’t forget to get vaccinated. Viruses change from year to year so check with your medical provider to see what you need.

And wash your hands…often! Your body won’t have to work as hard if you don’t allow the viruses and other germs to infiltrate in the first place.

Barbara Intermill is a registered dietitian nutritionist and syndicated columnist. She is the author of “Quinn-Essential Nutrition: The Uncomplicated Science of Eating.” Email her at [email protected].