The arrival of Covid-19, and the new vaccines to protect people from becoming infected by it, have brought a subject into sharp focus for people who want to understand how to stay safe: immunity.
Each of us has a complex immune system that detects and fights viruses (such as the common cold and flu) and bacteria (such as salmonella and tuberculosis)—which are referred to as “pathogens.” A pathogen is an organism that causes a disease for the “host,” or person, it infects.
How the immune system works
We are all born with an “innate immune system”—proteins and cells that constantly travel throughout the body and create barriers, such as mucus to stop pathogens and acids in the stomach to dissolve them, keeping us from becoming infected.
In addition, we each have an “adaptive immune system” which recognizes—and remembers—foreign invaders. Adaptive immunity is regulated by cells that create antibodies that will attack specific pathogens. Vaccines work by preparing our immune systems to recognize and then fight pathogens such as the flu or Covid 19.
Our immune system is genetic, but it is also affected by the environments we live in, and our daily habits.
Enter exercise, sleep and diet. A 2020 study by Brazilian researchers found that regular exercise of moderate intensity strengthens the immune system, and even suggested that exercise might be a tool to fight against Covid-19 virus infection.
Getting enough sleep also strengthens the immune system, according to Mathew Walker, Ph.D., author of Why We Sleep (Simon and Schuster, 2017) in which he cites numerous study results detailing how this works.
And what—and how much—we eat plays an important part, too. “Nutrition is a key modulator of immune function,” says Vijaya Surampudi, M.D., Assistant Professor of Medicine in the Division of Human Nutrition at University of California Los Angeles. “The field of immunonutrition is focused on understanding the interactions between nutrition and the immune system,” she says. “The impact of both overnutrition and undernutrition on immune function, immune-mediated disease, and associated complications has been scientifically established.”
Malnourished children die mostly from infections because their immune systems have been damaged. At the other extreme, people who carry excess fat, particularly excess visceral fat in the abdomen area, can suffer from a chronic immune response called inflammation—increasing their risk of heart disease and other illnesses.
No magic pill
Eating for a healthy immune system does not mean popping a particular supplement or drinking an herbal tea. No specific supplements can fortify your immune system, writes Jenna Macciochi, Ph.D., in her book Immunity: The Science of Staying Well (The Experiment, 2020)
Dr. Surampudi agrees: “There are no supplements at this time that are specifically recommended based on high-quality studies for treatment/prevention. Nothing will replace a balanced whole food, plant-based diet.”
“Eat within a calorie balance, and ensure plenty of good fats, phytonutrients, and fiber with quality carbs and diverse protein sources,” is Macciochi’s recommendation for strengthening the immune system.
Key nutrients for the immune system are protein, zinc, and vitamins A, C, and E, according to the American Academy of Dietetics. Eating fresh vegetables and fruit, which contain phytonutrients, provides many health benefits. “Some phytonutrients, fibers, vitamins, and fish oil fatty acids have immune-boosting, anti-inflammatory, and antioxidant activities,” says Dr. Surampudi.
Maintaining good health and a strong immunity is a life-long journey. As we age, our immune systems slow down and do not work as well in protecting us from disease. This is why getting exercise and sleep, and eating healthy, balanced meals, becomes even more important.