As we all learn to live with COVID-19, it's crucial to have the right tools for taking care of ourselves. Our immune systems are complex, and how well they operate depends on several factors, many of which are within our control.
Our day-to-day lifestyles directly impact the health of our immune systems. Making healthy changes to our daily habits can significantly impact our ability to handle all diseases, including viral and respiratory ones. It may seem all too simple, but the resilience of our bodies depends heavily on how well we nourish ourselves and how often we exercise.
How Diet Impacts The Immune System
When it comes to supporting a healthy immune system, diet matters. A well-functioning immune system needs a wide variety of macro and micro-nutrients. Macronutrients such as carbohydrates and fats provide the fuel our immune cells need to carry out their duties. Proteins, which are also macronutrients, are broken down into amino acids, the building blocks for generating new cells and essential immune system components such as RNA, DNA, antibodies, and cytokines.
Micronutrients include antioxidants such as vitamins A, C, and E, zinc, selenium, and plant polyphenols, which help fight inflammation and oxidative stress, preventing viral and bacterial infections and diseases such as cancer. These and many other micronutrients play specific roles in various anti-viral, anti-bacterial, and anti-inflammatory functions, making them crucial in our diets.
Processed, fried, and fast foods are pro-inflammatory and often deficient in essential micronutrients. Imbalanced diets that include too many of these foods compromise the ability of the immune system to protect against invaders. However, whole, unprocessed foods are rich in the nutrients necessary to keep our immune systems strong.
In particular, plant foods (fruits, vegetables, nuts, beans & legumes, seeds, mushrooms, herbs, and spices) are vital. They are potent sources of the nutrients necessary for modulating the immune system. They're also the only foods containing fiber, which feeds gut bacteria that also help regulate the immune system. Not having enough plant foods in the diet can lead to underlying nutrient deficiencies, making it harder to fight off infection.
Studies published during COVID-19 found that nutrient-dense plant-based diets were associated with better health outcomes. The COVID Symptom Study surveyed 592,571 participants and found that diets with the most fruits, vegetables, and other plant foods were associated with a 41% lower risk of severe COVID and a 9% reduction in infections at all.
Another study found that people who followed plant-based or pescatarian diets rich in vegetables, nuts, and legumes had a 73% lower risk of severe COVID-19. In contrast, those who ate low-carb, high-protein diets were 48% more likely to experience severe illness. Incorporating nutrient-rich plant foods while avoiding red and processed meats (which can be pro-inflammatory) can be protective against the worst outcomes of COVID-19.
Supporting The Immune System With Exercise
Of course, a healthy lifestyle is about more than just what you eat - it's also how much you move. Science also supports the notion that exercise can impact your ability to handle infections. A recent study in the British Medical Journal directly measured the physical activity of 65,361 adults, all of whom had a COVID-19 diagnosis. Researchers sorted them into groups based on low (less than 60 mins/week), moderate (60-149 mins/week), and high activity levels (more than 150 mins/week).
The highly active participants were less likely to be hospitalized, had lower ICU admission rates, lower rates of ventilation, and lower rates of death compared to those who were less active. People who were highly and moderately active fared significantly better with COVD-19 overall, suggesting that exercise has a protective effect. This protective effect was seen even in those with chronic medication conditions.
This study is just the latest of many that show that physical activity makes a huge difference in health outcomes from infections and diseases. A 2011 study compared participants with upper respiratory tract infections and found that those who regularly did five days or more of cardiovascular exercise had shorter, less severe infections. This finding suggests that lack of exercise can cause seasonal colds, flu, and other respiratory viruses to be longer and more severe than they have to be.
One review covering over 170 studies found that regular moderate-to-vigorous activity is essential for a healthy immune and inflammatory response. The science is clear: sedentary lifestyles leave people at risk for more prolonged and severe viral infections, from influenza to COVID-19.
So how, exactly, does exercise improve the immune system? Almost half of the human body is muscle. When we contract these muscles via movement and exercise, they release proteins vital for regulating various biological processes.
These muscle proteins, called myokines, are involved in hundreds of different functions, including helping muscle growth, supporting glucose metabolism, and regulating the immune system. Myokines have an anti-inflammatory effect and help maintain homeostasis between B and T cells.
Each bout of exercise produces these B and T cells, which are crucial to a healthy immune system. B cells attack invaders such as viruses, toxins, and bacteria, while T cells attack the cells in our body that have already become infected or cancerous.
Studies have found that exercise increases the proportion of healthy, anti-inflammatory cells while decreasing the accumulation of cells that have become defective and cannot perform optimally. The optimal performance of these cells is what keeps our immune system in tip-top shape, ready and able to mount a strong defense against possible invaders.
When we don't move enough, we rob ourselves of opportunities to strengthen and maintain our immune system through muscle contractions. Going on a brisk, 30-minute walk each day or weight training 2-3x per week can help fortify your immune system. Even doing yoga a few times per week can be beneficial. While it may not prevent you from catching COVID-19 or any other viral infection, it will significantly reduce the severity and your risk of needing hospitalization.
Other Lifestyle Factors
In addition to diet and exercise, getting adequate sleep, staying hydrated, and managing stress can all help to keep our bodies healthy, making us more resilient against all kinds of illness and disease.
Infections and diseases can be scary, often causing feelings of hopelessness. But you have more power than you think. Your daily choices can make all the difference in how well your body can fight off whatever comes its way.
Niv Mullings is a Plant-Based Nutrition & Fitness coach from the Bronx, New York. After years of struggling with obesity, anxiety, depression, painful menstruation, and other chronic health complaints, Niv changed her life for the better through fitness and a healthy plant-based diet. Now she helps others to do the same.