When Leslie Bonci talks about what to eat, people listen.

Bonci is a local nutritionist with a big national following. She consults for the Kansas City Chiefs, Carnegie Mellon University athletics and the National Dairy Council. She was also the sports dietitian for the Steelers, Pirates, Penguins and the Women’s National Basketball Association.

Her first message? You are in control.

“The reality is that we have that ability to control what we choose to eat or choose not to eat from the standpoint of helping to support a healthy immune system. That’s the goal right now,” says Bonci. “That would certainly be the goal any winter, but it’s critically important right now as we’re all doing the best we can to stay healthy.”

An array of foods that support the immune system. Photo courtesy of Leslie Bonci.

Bonci warns that you should be skeptical of anything claiming to “boost” your immune system — there are a lot of health products that make that claim. However, you can support your immune system through what you eat, which is an important distinction.

“It’s physiologically impossible to boost it,” says Bonci. “So, supporting it means that we’re doing the right things, taking care of all aspects of keeping your cells healthy.”

A lot of people think they can take an immunity chewable or a CBD caramel and call it a day but that’s not good enough.

“The reality is that the immune system or 75% of our immune system is in the gut,” she says. “We really have to make sure that we eat the things that help support a healthy microbiome where there’s good bacteria in the gut.”

Here are the things your body needs to support its immune system, Bonci notes:

Carbohydrates. Think whole grains, fruits and vegetables, and dairy foods like yogurt and milk. “The carbohydrate is a critical component of supporting a healthy immune system,” adds Bonci. Number one, carbohydrates help to reduce stress hormones. And they support the good bacteria in the gut because they provide the foods for the probiotics in the gut.”

Protein. “Protein helps to support white blood cell formation, and that’s important for supporting a healthy immune system,” says Bonci. You can get protein with meat, poultry, fish, shellfish, dairy and eggs. Or plant-based foods such as beans, peas, lentils and nuts.

• Vitamin D. Obviously, in a gloomy Pittsburgh winter, you won’t get much D from the sun. “It has a role to play in supporting the lymphocytes, which are the body’s defense mechanism to keep our immune system healthy,” says Bonci. She suggests you eat salmon, trout, even certain mushrooms and cereals that are fortified with vitamin D.

• Vitamin C. No, taking a 1,000-milligram Airborne supplement is not the answer. “You need to have enough vitamin C, but more is not necessarily better,” says Bonci. “It needs to be at least 200 milligrams a day. And sometimes a little bit more if we’re feeling somewhat under the weather. So citrus fruits, citrus juice, peppers, broccoli, potatoes, kiwi, strawberries and tomatoes are all sources of vitamin C.”

• Zinc. Zinc is another thing your immune system needs because it’s an antioxidant. It can be found abundantly in oysters, red meat and fortified breakfast cereals. “It may also help in the first 24 hours after onset of infection, to help to suppress that infection, to a certain extent,” explains Bonci. “But again, it’s not just like taking a zinc lozenge, and then I don’t think about the rest of my diet. It’s one thing among many.”

• Probiotics. “Probiotics are the good bacteria, and we want to have enough of them in our gut,” explains Bonci.  Yogurt and kefir (a fermented milk drink), kimchi, pickles and sauerkraut are all good for this. Think: things that are fermented.

• Omega-3. Fatty acids also have a positive effect on your immune system. They’re primarily found in coldwater fish, so salmon is a big one, along with mackerel, walnuts and chia.

And note as you take stock of your diet. “It’s not just one thing, it’s all of those things together that really help to support a healthy immune system and do a better job overall of nourishing the body,” says Bonci.

So what would that ideal plate look like to support your immune system?

It would be a plate that would be 50% produce — fruits and vegetables — about 30% protein, such as fish, poultry or tofu, and the remaining 25% coming from a grain such as pasta, rice, quinoa or potatoes, she says.

Fresh produce isn’t the only way to get these nutrients in the winter. Frozen is fine, she says, and canned goods, especially canned fish work. “That’s simple,” Bonci says, “It’s cheaper and it works.”