How often do you think about your immune system? Probably much more these days than you used to.
What is the immune system?
The human immune system is an intricate network of specialized tissue, organs, cells, and chemicals. The lymph nodes, spleen, bone marrow, thymus glands, and tonsils all play a role in fighting off germs and illness. Treat the immune system as another facet of your being – like diet, sleep, and exercise – that needs daily attention and care.
«Most people don’t realize that 70% of the immune system resides in the gut.»
Your first Line of defense
Your immune system has different lines of defense to protect you in different ways. Your first line of defense between your body and the outside world needs to be strong and intact to keep germs out. Most people don’t realize that 70% of the immune system cells reside in the gut. This is where your gut bacteria live and why they are so important. When occasionally invaders do get through the immune system there is a second line of defense and a final line of defense.
Keeping germs out
The best way to keep germs out is with a daily routine of healthy whole-foods, drinking the right amount of clean water, adequate sleep, exercise, and stress reduction.
Nutritional habits that strengthen immunity
Be Seasonal. Winter foods like sweet potatoes, beets, and squashes provide fiber, beta carotene, and vitamin A and C. Eat warming food like stews, beans, and soups.
Add Colour to your plate. Fruits and vegetables get their rich colours from phytochemicals. These phytochemicals support the plant from invaders. The more colours you eat, the more broad-spectrum your immunity will be. Eat dark greens, yellow and orange squash, carrots, yams, red peppers, and tomatoes.
Focus on food high in antioxidants. Antioxidants help your body resist illness because they protect cells against harmful free radicals and oxidative stress. Blueberries are particularly beneficial and maintain their nutrients even when frozen, blend half a cup of berries into your morning smoothie.
Balance your pH. The typical western diet contains processed foods, sugary treats, and refined snacks that produce acid in the body creating an environment in which bacteria thrive. Eat at least 10 serving fo alkalizing foods per day to optimize your body’s immune response. Spinach, broccoli, and cauliflower are great choices, along with almonds, olive oil, and grapes.
Aromatic herbs. Garlic, ginger, and spring onions provide prebiotics for the bacteria that act as the first line of immune defense. These herbs open up the sinuses and the chest and cause light perspiration. Soups seasoned with these herbs should be part of your regular meals to strengthen immunity.
Choose healthy fats. Wholesome fats like Omega3 fatty acids found in cold-water fish and some vegetable oils such as flaxseed, help the immune system’s cells function more efficiently to detect and prevent germ attacks.
Ditch sugar and reduce dairy. Refined sugars in sweets and sodas can deplete your immune system. Instead of desserts and cereals, try eating fruit. Dairy can also cause the body to produce more mucus, so try reducing your intake during Winter and avoid dairy during times of illness.
Checklist: Immune-supportive foods
Garlic. This onion offers antioxidant flavanoids and sulfur-containing compounds that help to support a healthy inflammatory response. Aim for two cloves daily. Before heating, allow chopped garlic to rest for five minutes.
Green Tea. All herbal teas offer health benefits, but green tea has more polyphenols. Drink it warm or cold and enjoy throughout your day with honey and lemon. Fresh thyme leaves also make a tea that clears and soothes the upper respiratory tract.
Kale. This cruciferous vegetable offers more vitamin C than almost any other dark green leafy vegetable. Steam kale for five minutes, toss with lemon juice, flaxseed oil, and cayenne; add to soups or pasta. Aim for 2-3 servings of C-rich vegetables daily.
Mushrooms. Mushrooms are a good source of vitamin D. Exotic shiitakes and maitakes mushrooms have been reported to strengthen immunity.
Oats. Along with apples and nuts, oats are a good source of soluble fiber, which stimulates the production of anti-inflammatory protein interleukin-4, which helps support a healthy immune system. Polysaccharides called beta-glucans, found in oats, barley, mushrooms, and Baker’s yeast, also help strengthen the immune system.
Fermented foods. Probiotics found in kefir, kombucha, and sauerkraut have been shown to reduce the duration and severity of colds and flu.
Pumpkin seeds and brazil nuts. Along with chickpeas, oysters, eggs, and red meat, pumpkin seeds are a great source of zinc, an essential mineral for cellular function, including immune cell production. Even small zinc deficiency can suppress the immune system. Brazil nuts are a good source of selenium which also supports immunity. Grind up nuts and pumpkin seeds and add them to granola, oatmeal, salads, and vegetable dishes.
Bone broths. Mineral bone broths are packed with nutrients and minerals which strengthen the immune system, keep the mucus membranes moist, and help to wash away germs that enter through the nose and throat.
Vegetable juices. Juicing vegetables is a great way to get in a variety of vegetables in one glass. Juiced vegetables are also easy to drink and digest when you are not feeling well. Juice carrot, orange, and ginger or blueberries, spinach, and pineapple.
Melini et al. (2019) Health-promoting compound in fermented foods. Nutrients.
Murray, M. J. & Pizzorno, L. (2017). Bottom Line’s Encyclopedia of Healing Foods. Stamford, CT: Bottom Line Books.
Low Dog, T. (2016). Fortify your life: Your guide to vitamins, minerals, and more. Washington, D.C.: National Geographic Society