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Want to Avoid Getting Sick? Here Are Some Tips to Boost Your Immunity

Image of Everything you eat matters. Eating a nutritious diet and having positive social connections are part of the tools that can boost your immunity and help ward off disease. Personal Protective Nutrition tips include eating a wide variety of types and colors of foods to boost your immunity and make you resilient against illness. (Graphic: Kim Farcot, MHS)

In the same way that wearing personal protective equipment like gloves, goggles, and masks can minimize your exposure to hazards that cause serious workplace injuries and illnesses, personal protective nutrition and lifestyle practices can do the same to boost your immunity.

This is especially relevant this season, when a “tripledemic” collision of respiratory syncytial virus—known as RSV, the flu, and COVID-19 – are affecting the population and overwhelming hospitals across the United States.

“Personal protective nutrition and personal protective lifestyle are evidence-based strategies to boost your immune response to reduce the risk of severe illness associated with COVID-19 and other infectious diseases,” said U.S. Air Force Col. (Dr.) Mary Anne Kiel, chair of the Air Force Medical Readiness Agency’s Lifestyle and Performance Medicine Working Group. “They are additional measures that we can take to improve our resilience and optimize military readiness and performance.”

PPN includes optimizing your nutrition by eating mostly unprocessed foods from plant sources, she explained. This means drinking enough water to stay hydrated and aiming to get most vitamins and essential nutrients from whole food sources, thus being selective about which types of supplements to take. 

“PPL includes getting seven-to-nine nightly hours of restorative sleep, learning tools to manage stress, staying physically active every day, maintaining positive social connections, spending time in nature, practicing mindfulness, and avoiding risky substances like tobacco and alcohol,” added Kiel.

Taste the Rainbow

“Eating a healthy diet is one of the most profound ways that we can have a positive impact on our health and well-being, including our immune system,” said Kiel.

Considering that “eating is something we typically do two-to-six times per day, being selective about the types of foods we fuel our body with can significantly boost our ability to fend off and fight infections when our immune system encounters them,” said Kiel.

Consuming a wide variety of types and colors of fruits and vegetables helps us maximize the nutrients our immune system has to build a protective response, including phytochemicals, vitamins, minerals, and fiber.

“It gives our immune system the best building blocks to create a defense against infections and other non-infectious chronic diseases like type 2 diabetes, heart disease, autoimmune diseases, and others,” said the expert.

Personal Protective Nutrition (PPN)

Eat a well-balanced diet to optimize your immunity:

  • Drink plenty of water. Divide your body weight (in pounds) by two, and aim to drink that many ounces of water a day.
  • Build a power plate. Fill your plate with 50% veggies, 25% whole grains, and 25% lean protein. Visit to learn more.
  • Eat high-fiber and protein. Consume a variety of veggies, legumes (beans and peas), grains, and fruits for fullness. Try plant-based proteins too.
  • Go anti-inflammatory. Use fresh herbs and spices, eat healthy fats (olive, sunflower, or avocado oils), avoid foods with added sugar, and minimize fried or processed foods.
  • Eat the rainbow. Foods rich in color have high amounts of antioxidants, so eat your berries, greens, and other colorful foods.
  • Protect your gut. Eat grains (brown rice, couscous, or quinoa), veggies, and fermented foods (yogurt, kimchi, and sauerkraut) for better digestion.
  • Get the scoop on supplements. Ask your healthcare provide about supplement such as vitamin D, vitamin C, zinc, magnesium, and omega-3.

What the Research Shows

There is ample research to support the benefits of a healthy diet in warding off disease.

For example, studies show that about 70%-80% of our immunity resides within the cells of our gastrointestinal tract, said Kiel.

Given that the foods we eat “impact the composition of the bacteria and fungi living within our gastrointestinal tract,” this is key for our immune health.

The American Gut Study “found that people who included more than 30 different types of plant foods in their diets each week—including fruits, vegetables, grains, legumes, nuts, and seeds—had a much more diverse microbiome in their intestinal tract,” she said.

Specifically regarding COVID-19, a study the National Institutes of Health published in 2021 concluded that a high-quality diet consisting primarily of healthy plant-based foods, was associated with decreased risk and severity of COVID-19.

Another 2021 NIH study found that the micronutrients consumed in a diet that contains a diversity of plants play important roles in supporting the response to COVID-19 vaccination.

And a study published in the nutrition journal BMJ Nutrition, Prevention & Health, “showed that people who self-reported following plant-based diets and pescatarian diets [meaning they consume fish but no other meats] had significantly lower odds of experiencing moderate-to-severe COVID-19,” said Kiel.

Effects of Processed Foods

Processed foods—food that is altered from its natural state—can negatively affect our health and ability to prevent infection, explained Kiel.

These processes refer to any alteration in the way a food is cooked or packaged, including adding preservatives, flavors, nutrients, salts, sugars, or fats.

“By their nature, processed foods often have significantly less fiber and much more salt, oil, sugar, and fat compared to whole foods,” said Kiel. 

Yet also, “highly processed foods such as microwave meals, bagged snacks, sweets, processed meats, and sweetened beverages all increase inflammation and are best avoided,” said U.S. Air Force Col. (Dr.) Sarah Vick, a family and preventive medicine physician at the Defense Health Agency’s Armed Forces Health Surveillance Division.

“Everything from runny noses to fevers to body aches can be traced to the immune system’s inflammatory response,” she added.

As a result, consuming processed foods causes the body to absorb fewer whole nutrients, potentially triggering “inflammatory responses and disease associations such as autoimmune diseases and perhaps other chronic inflammatory diseases and metabolic disorders,” said Kiel. 

Not Just Food

Consuming a healthy diet is important but it’s just one tool to boost your health and immunity. Living a stressful life without enough rest, activity, or healthy social connections can also be detrimental to your health.

“Just as eating a variety of plants and engaging in moderate exercise can decrease inflammation and susceptibility to infections, a poor diet, poor sleep, and being sedentary can increase inflammation and susceptibility to infections,” added Vick.

And even though stress is unavoidable, “learning how to respond to stress in a healthy and positive way can be the difference in our ability to thrive and maintain resilience in challenging situations,” said Kiel.

Tools for responding to stressful situations include prioritizing self-care and making time to laugh, says the wellness expert.

It “can help us destress and improve performance, in addition to strengthening our immune system.” 

For example, “engaging in self-care activities helps reduce cortisol [our stress hormone] and boosts other positive hormones such as dopamine, serotonin, oxytocin, and endorphins to reduce inflammation in our bodies, promote a strong immune system, and reduce our risk of developing chronic disease,” she added.

These hormones have key roles: Dopamine is the body’s the feel-good hormone, serotonin regulates our moods and other functions, oxytocin plays a role in social bonding and reproduction, and endorphins trigger positive feelings.

Personal Protective Lifestyle (PPL)

Engage in activities that boost your immune resilience and optimize performance.

  • Get your Zzzs. Reset your brain with 7–9 hours of restorative sleep nightly and stick to consistent sleep and wake times.
  • Practice mindfulness and STOP. Stop, Take a breath, Observe your thoughts and feelings, and Proceed with hope.
  • Reflect on what’s good. Develop a resilient mindset by seeking the good in situations. Find opportunities to learn, grow, and be innovative. And if you need help, ask for it.
  • Move more. Performa at least 30 minutes of moderate-intensity physical activity 5–7 days a week.
  • Connect with others. Share meals, walks, and workouts. Prioritize relationships that nurture you.
  • Spend time in nature. Take regular breaks from technology and go outside for 15–20 minutes in the fresh air.

In addition, “getting high quality, screen-free sleep allows the body time and resources to repair itself,” said Vick. 

“Sleep is a critical facet for boosting our immune resilience and optimizing performance,” said Kiel.

She highlighted that improved sleep duration and quality can produce almost instantaneous results for improved mental health, pain levels, and risk for infectious disease. 

“In fact, studies have shown that sleeping at least eight hours daily on a consistent basis is linked to fewer colds, by a factor of three to four-fold,” she said. 

During sleep, our brain works to remove toxins that have built up during the day and allows our mind and body to recharge, repair, and reenergize, she added. 

Physical activity is also key.

“Moving the body lubricates muscles and joints, preventing stiffness and pain caused by inflammation,” she said. “Moderate physical exercise gives the added bonus of ramping up the immune system with elements that fight viruses including RSV, COVID-19, and influenza.”

To learn more about PPN and PPL practices to help you remain healthy, strong, and better able to avoid viruses and illness, contact your health care provider.

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Last Updated: July 11, 2023
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