Keep your immune system in top form this cold and flu season, and beyond.
Fall is in the air. It's sweater weather, pumpkins spice lattes are back, and the holidays will be here in no time. But, in spite of all the festive cheer, something sinister lurks just around the corner: cold and flu season. Fortunately, there's still time to make sure your immune system is fully fortified and ready to face whatever comes around this year.
Your Immune System
You probably don’t give your immune system much thought—and that’s a good thing. When things are running smoothly, the immune system is able to fight off disease-causing germs like bacteria, viruses, parasites, and fungi and remove them from the body without a hitch. It’s also responsible for recognizing and neutralizing harmful environmental substances, as well as combating chronic disease-causing changes in the body.
Your immune system has two components that accomplish these tasks: the innate immune system and the adaptive immune system. The innate immune system is your body’s general defense mechanism against harmful germs and substances. It sends out immune cells to ward off unwelcome intruders that enter the body. The adaptive immune system—also called the acquired immune system—produces antibodies to fight certain germs that you’ve encountered before. Both of these systems are closely linked and work together any time a germ or bad actor provokes an immune response.1
How to Boost Immunity
But just because your immune system may be working without complications now doesn’t meant that it couldn’t use some extra support. Here are some safe and effective ways to ensure your body is protected this cold and flu season.
Exercise and the Immune System
Physical activity, even small amounts, can work wonders for your immune system. Studies consistently show that regular exercise dramatically diminishes the dangers of inflammation, excess body mass, disease, and even mortality.2 It can also:
Reduce illness severity. Unfortunately, regular physical activity can’t totally prevent you from coming down with something every now and then, but it can help you get through it more quickly with less severe symptoms. For instance, research suggests that regular exercise can reduce the incidence, duration, or severity of upper respiratory tract infections. But there’s a catch: although exercise of any intensity is good for your health, these benefits come from moderate- to high-intensity physical activities.3
Relieve stress. Chronic stress can weaken your immune system and increase your risk for disease. But exercise eases stress and anxiety while improving innate immunity and protecting against viral infection.4 How much is enough? The current guidelines recommend a minimum of 150 minutes of moderate-intensity aerobic activity with two days of strength training per week. So go for a bike ride, swim, or hike most days of the week—and include some resistance exercises with weights or bands every couple of days. But don’t overdo it. Overtraining or strenuous exercise, like running a marathon, can actually undermine your immune system and leave you more prone to illness.5
Foods That Keep the Immune System Strong
A strong immune system starts with the foods you eat. A healthy and balanced diet gives your body the nutrients is needs to fight against infections and viruses. Here are a few food groups worth focusing on:
Protein. Not just for building strong muscles, protein is critical for a strong immune system. Evidence shows that being deficient in dietary protein can hinder immune function and increase your risk of infection.6 That’s because protein contains essential amino acids that play vital roles in the immune system, such as regulating adaptive and innate immune cells, increasing lymphocytes (a type of white blood cell that helps your body fight off bacterial and viral intruders), and producing antibodies, cytokines, and other important immunity components.7
The Food and Drug Administration recommends that adults consume at least 50 grams of protein per day. But instead of trying to keep track of each gram, include a palm-size protein portion with every meal. For example, start with a couple of eggs for breakfast, turkey chili for lunch, and salmon for dinner. If you get hungry between meals, snack on almonds or pumpkin seeds for a satiating protein boost.
Antioxidants. Critical for healthy aging, antioxidants protect your body against harmful free radicals that cause oxidative stress—a problem that has been linked to a number of diseases.8 The best way to get plenty of these immune-supporting compounds is to fill your plate with colorful produce. A 2020 study found that the foods with the most antioxidants are magenta, blue, and red fruits and vegetables.9 That was backed up by another report showing antioxidant-rich berries, like blueberries, strawberries, and raspberries, enhance the immune system and help to guard against significant diseases.10
Probiotics. Your gut is home to more than 70 percent of the immune cells in your body.11 That’s why keeping your gastrointestinal tract in top form is essential during cold and flu season. Eating foods that contain live probiotics such as yogurt, kimchi, kefir, and sauerkraut can promote a healthy gut and therefore a healthy immune response. A recent report in the journal Nutrients shows that dietary probiotic consumption is tied to a lower incidence and duration of infections in both children and adults.12
Supplements for Optimal Immune Function
The reality is, no one’s diet is perfect all of time. That’s where supplements come in. Supplements can fill in any nutritional gaps you may experience so you can keep your immune system in top shape even when life gets in the way. Try one or preferably more of the following supplements to reinforce your diet and stop any would-be illness in its tracks.
Vitamin C. Perhaps the best-known immunity supporter, vitamin C is critical to proper immune function. Research shows that not having enough of this key nutrient impairs immunity and increases the chances that you’ll get sick. Fortunately, taking a vitamin C supplement can effectively stabilize your levels to help fortify your immune system and prevent infection. And when you do get ill, ample stores of vitamin C can shorten the duration of your symptoms.13
Aged Garlic Extract. Garlic has a long history of immune system protection. And research published in the Journal of Health shows why: In a controlled trial during cold and flu season, healthy participants, aged 21 to 50, took either 2.56 grams of aged garlic extract or a placebo every day for 90 days. Participants in the garlic group that did get sick showed reduced cold and flu severity, including a reduction in the number of symptoms, the number of days they functioned sub-optimally, and the number of work or school days missed. The placebo group showed no such benefit.14
Olive leaf. Though olive oil gets a lot of attention for its powerful health benefits, olive leaves are also bursting with a wealth of nutritious compounds. In fact, olive leaf extracts contain higher amounts of beneficial polyphenols than those found in extra-virgin olive oil.15 Polyphenols act as antioxidants, which defend your body from cell damage. And a recent study showed that the polyphenols from olive leaf can not only help bolster immune function but also help increase energy levels, lower blood pressure, and support the cardiovascular system.16
Astragalus. An ancient herbal medicine, astragalus is another immune booster worth including in your supplement routine. Evidence suggests that astragalus increases lymphocytes.17 It’s been shown to possess antioxidant activity that works to prevent tissue injury as well.18
You’re bound to come in contact with a bug sooner or later. But trying out these immunity-building tips can help safeguard you against whatever comes your way. Here’s to staying healthy and cold- and flu-free this fall and winter!
- Institute for Quality and Efficiency in Health Care (IQWiG). How does the immune system work? InformedHealth.org [Internet]. 2006.
- Fletcher GF. Promoting physical activity and exercise: JACC Health Promotion Series. Journal of the American College of Cardiology. 2018;72(14):1622–39.
- Laddu DR. Physical activity for immunity protection: Inoculating populations with healthy living medicine in preparation for the next pandemic. Progress in Cardiovascular Disease. 2021;64:102–4.
- Ranasinghe C. Exercise and well-being during COVID 19 – time to boost your immunity. Expert Review of Anti-infective Therapy. 2020;18:12, 1195–1200.
- Nieman DC. Marathon training and immune function. Sports Medicine. 2007;37(4-5):412–5.
- Li P. Amino acids and immune function. British Journal of Nutrition. 2007;98(2):237–52.
- Tourkochristou E. The influence of nutritional factors on immunological outcomes. Frontiers in Immunology. 2021;12.
- De la Fuente, M. Effects of antioxidants on immune system ageing. European Journal of Clinical Nutrition. 2002;56 (Suppl 3):S5–S8.
- Cömert ED. Relationship between color and antioxidant capacity of fruits and vegetables. Current Research in Food Science. 2020;2:1–10.
- Tomovska J. Review of antioxidants in fruit berries and its impact in immune system. Asian Journal of Plant and Soil Sciences. 2021;6(1):136–47.
- Wiertsema SP. The interplay between the gut microbiome and the immune system in the context of infectious diseases throughout life and the role of nutrition in optimizing treatment strategies. Nutrients. 2021;13(3):886.
- Lehtoranta L. Role of probiotics in stimulating the immune system in viral respiratory tract infections: A narrative review. Nutrients. 2020;12(10):3163.
- Jafari D. Vitamin C and the immune system. Nutrition and Immunity. 2019:81–102.
- Percival SS. Aged garlic extract modifies human immunity. Journal of Nutrition. 2016;146(2):433S–6S.
- Magrone T. Olive leaf extracts act as modulators of the human immune response. Endocrine, Metabolism, and Immune Disorder Drug Targets. 2018;18(1):85–93.
- Borjan D. Microbiological and antioxidant activity of phenolic compounds in olive leaf extract. Molecules. 2020;25(24):5946.
- Liu J. Systematic exploration of Astragalus membranaceus and Panax ginseng as immune regulators: Insights from the comparative biological and computational analysis. Phytomedicine. 2021;86:153077.
- Shahzad M. The antioxidant effects of Radix Astragali (Astragalus membranaceus and related species) in protecting tissues from injury and disease. Current Drug Targets. 2016;17(12):1331–40.
This article is for informational purposes only. This article is not, nor is it intended to be, a substitute for professional medical advice, diagnosis, or treatment and should never be relied upon for specific medical advice.