The immune system has been a hot topic this year perhaps more than ever. With the ongoing outbreak of COVID-19, people understandably want to know more about what they can do to help boost their body’s natural defenses to help them stay healthy. 

As a functional nutrition dietitian, my goal is always to educate others on how to use food and lifestyle habits as medicine to both treat and prevent disease. This whole-body approach applies to the immune system as well and there many ways you can support your immune system and internal defenses along-side mask wearing, social distancing and handwashing.

Here I will break down how the immune system works and explain how you can apply a variety of diet and lifestyle habits to help boost your immunity and protect your health. 

What is the immune system and how does it work?

The immune system is a complex network of cells, tissues, and organs in your body that serve as a barrier to prevent and treat infections that can cause disease. Without it, you would constantly be getting sick and be unable to recover. Your skin, blood, bone marrow, gastrointestinal tract, and lymphatic system all play important roles in the immune system. 

The immune system can distinguish between normal, healthy cells and harmful, unhealthy cells. When things like viruses and bacteria enter the body, the immune system recognizes these as harmful and releases signals to address the problem. 

There are two main types of immunity: innate and adaptive. Innate immunity is the first line of defense against germs that enter the body. It is sometimes referred to as the nonspecific immune system because it responds the same way against all foreign substances. Adaptive immunity is the second line of defense that takes over if innate immunity is not able to destroy all of the germs. It is more specific and effective at fighting off invaders and has the benefit of being able to remember germs so that it can respond more quickly the next time they try to enter the body. 

People with weakened immune systems have a greater likelihood of becoming infected than those whose immune system is strong and functioning properly. Some things that can weaken the immune system are out of your control, such as genetics, autoimmune disorders, advancing age, and exposure to environmental toxins. However, other factors such as smoking, drinking excessive alcohol, and eating a poor quality diet that lacks variety are also known to weaken its defenses. 

Diet and lifestyle habits to help boost your immune system

Perhaps the best thing you can do for your immune system is to build up its resilience. This means that even when you may come into contact with harmful invaders, your body will be in an optimal state and will have the tools it needs to fight them off so that you don’t get sick or have the ability to rebound quickly.

Thankfully, there are many diet and lifestyle habits that help your body do just this. 

These include:

• Food- good nutrition is vital for the health and function of all cells, including immune cells. Having nutritional deficiencies can weaken the immune system, so eating a diet that includes a variety of whole foods is one of the best and easiest places to begin when supporting a strong immune system. 

Specific foods to focus on include:

• Fiber. Dietary fiber promotes the growth of beneficial bacteria in the gut, which is super important for supporting optimal immune function. Research shows that about 80% of immune cells are located in our gut tissues, and the bacteria in the gut play a crucial role in regulating immune function.

  • High fiber foods include beans, nuts, seeds, fruits and vegetables, and whole grains like oats, fruit, quinoa, and brown rice. 

• Antioxidants. These powerful plant compounds support the immune system by helping fight off free radicals which can cause damage to cells, trigger inflammation, and contribute to disease. Vitamins C, E, A, and selenium are all sources of antioxidants that protect the function of immune cells. Antioxidants are key plant compounds found in many different types of foods.

  • Good food sources of antioxidants include colorful fruits and vegetables, nuts, dark chocolate, herbs, and green tea.

• Pre and probiotics. In addition to fiber, pre and probiotics are the other biggest factors that support a healthy digestive tract, which in turn support immune function. Probiotics are beneficial bacteria that strengthen the health of your gut. Probiotics help to create an unfavorable environment for bad bacteria along with supporting mucosal and systemic immune systems. Prebiotics serve as food to help the probiotics work most effectively, as well as supporting the production of byproducts that fuel the health of the gut. Studies suggest that probiotics can be an effective approach for both disease prevention and treatment.

  • Probiotic foods include fermented vegetables like kimchi and sauerkraut as well as miso, tempeh, some yogurts, and kombucha. They can also be taken in supplement form, and Scientists have found that the combination of the lactobacillus and bifidobacterium strains have been specifically helpful in providing general support to the immune system. 

  • Prebiotics are specific fiber that come from foods like leeks, asparagus, bananas, and garlic. 

• Protein. Protein is made up of amino acids, which are used as fuel for the immune system. Research shows that not eating enough protein can lead to weakened immunity and a higher risk of developing disease. 

  • High quality meat, fish and poultry as well as beans, nuts, seeds, and organic full fat dairy and soy products are all good sources of protein. 

• Omega-3 fats. These fats help boost the body’s response to pathogens because of their anti-inflammatory properties. While a low level of inflammation is a normal response to injury, chronic inflammation can weaken the immune system. Studies show that eating omega-3 fatty acids can help decrease disease risk. 

  • Food sources include fatty fish like salmon, tuna, and sardines as well as chia, flax and hemp seeds and walnuts. Omega-3’s can also be taken in supplement form from fish and cod liver oil and algae.  

• Sleep. Inadequate or poor quality sleep increases your risk for getting sick. Research shows that adults need 7 or more hours of sleep each night, and getting less than this is linked to weakened immune function. Having a consistent bedtime and practicing good sleep hygiene such as turning off screens 90 minutes before ned, sleeping in a dark and cool room, and doing what you need to relax your mind before bed can help you achieve better sleep. 

• Stress management. Chronic stress, which can be both mental and physical, contributes to inflammation and weakens the immune system responses. Therefore, keeping your stress levels under control is support important for immunity. Self-care activities like meditation, journaling, gentle exercise, and talking with loved ones for support can be helpful stress relievers. 

• Exercise. Exercise benefits the immune system in many ways. It can help reduce inflammation, control stress levels, and improves immune function to help strengthen your body’s natural defenses. The key with exercise, though, is to not overdo it, since excessive exercise can actually lead to more stress on the body and weaken immunity. Find activities that you enjoy and aim to incorporate a variety of cardio and strength based movement along with walking, stretching and recovery days.

• Strategic supplementation. While whole foods should always be the first focus for getting foundational nutrients, supplements are warranted to help fill in the gaps and provide additional therapuetic support. Research shows that supplements like elderberry, echinacea, garlic, vitamin C, vitamin D and zinc all play important roles in improving immunity. In regards to COVID-19, this is a helpful reference for virus-specific nutraceuticals and botanicals.

Bottom Line

Your immune system is a super important part of your body that needs support to function at its best. A variety of foods, supplements and lifestyle habits can play important roles in strengthening immunity all year long. It’s always best to receive personalized guidance when making changes to your diet and lifestyle, so please feel free to reach out to me for support or consult with your healthcare provider.