Influenza, or the flu, is a contagious viral infection of the respiratory system with two common strains that effect humans: A and B. Strain A has many subtypes, changing constantly, and it can cause illness on an epidemic level. Strain B is typically less severe.1
Because the flu thrives in colder environments, it commonly affects people between November and March in the northern hemisphere and between May to September in the southern hemisphere. Moreover, the harsh conditions of winter force people to stay indoors, often in close contact with others, which encourages the spread of the virus by way of coughing, sneezing, or exhalation of tiny mucus droplets into the air. Hand-to-hand contact can also cause the virus to spread. The flu virus can spread quickly, and infects over 10 percent of Americans every year. Approximately 200,000 people require hospitalization from complications related to the virus, and about 36,000 people die from the virus annually in the United States.1,2
Influenza incubates in the body for 2 to 4 days before symptoms manifest, which include runny nose, sore throat, dry cough, muscle aches, joint aches, headache, weakness, fatigue, and fever. While the cough and fatigue can persist for several weeks, the fever usually subsides in 2 to 5 days. Complications from the virus can lead to the development of pneumonia, asthma attacks, ear infections, sinusitis, bronchitis, and inflammation of the heart, nervous system, and muscles. Fighting the flu weakens the body’s immune system, which predisposes some individuals to develop pneumonia, a serious, and sometimes fatal, bacterial infection of the lungs, which tends to set in toward the end of influenza recovery.1,2
In people with normal immune systems, the flu usually takes 1 to 2 weeks from which to recover, but there are things you can do to help your recovery along while also helping to prevent more serious complications that can occur. Research points to several foods with specific nutrients that can potentially aid in the recovery process.
Broth. Broth made from vegetables and/or meat is easily digestible and hydrating, and the salt in the broth helps the body hold the water. The warm liquid can help to ease a sore throat and increase hydration. In time, as your appetite returns, adding vegetables and spices will provide your body with even more beneficial nutrients.3
Garlic. Though the idea of ingesting raw garlic might be hard to stomach, research suggests that compounds found in garlic have the power to boost the natural killer cells in our bodies that fight and remove harmful stimuli. Enhancing the body’s immune response can mitigate the symptoms, severity, and length of a bout of influenza. Chopped, raw garlic can be added to broth, soups, and smoothies.4
Oats. Along with antimicrobial and antioxidant properties, the beta-glucan fiber in oats has been shown to improve the immune system and reduce inflammation. Consumption of oats has also been linked to a decreased risk for upper respiratory tract infections (URTI) that can occur from exercising. Oats also contain protein, which can assist in boosting energy and fighting excessive fatigue. A bowl of oats mixed with water or milk is easy on the stomach and digestive track.5
Vitamin C. Vitamin C remains the most loyal comrade of the immune system: it assists in the production of antibodies and interferons—proteins released by the body in response to viral infection—and phagocytes, boosting the nitrogen oxide they produce, as well as cytokine and t-lymphocyte production—all of which play a role in either optimizing the body’s tissue and cell levels or destroying harmful pathogens.6 Moreover, vitamin C has been shown to prevent and treat respiratory infections, so consuming foods rich in this vitamin can keep viral infections at bay. Kale, kiwi, lemons, cauliflower, oranges, sweet potatoes, strawberries, broccoli, cantaloupe, and pineapple are all excellent sources of vitamin C. These foods can be prepared in a variety of ways: fruits and leafy greens can be turned into smoothies and ice pops for a sore throat, fruit can be added to oatmeal or eaten alone for those with a wavering appetite, and vegetables can be cooked with broth for a hearty, hydrating soup.6
Vitamin E. Vitamin E keeps the immune system going. It’s a strong lipid-soluble antioxidant found in the cells that regulate your immune system and reduce risk of infection and inflammation. Vitamin E impacts the function, membrane integrity, and division of T-cell lymphocytes, white blood cells that play an integral part of your immune system and influence susceptibility to infectious diseases, such as respiratory infections and allergic diseases. Green, leafy vegetables, such as raw Swiss chard, steamed kale, raw spinach, cooked beet greens, sunflower seeds, almonds, avocado, mango, and blackberries have high levels of Vitamin E.7,8
1. Harvard Health Publishing site. Diseases and conditions. Influenza: How to prevent and treat a serious infection. Updated 9 Aug 2019. https://www.health.harvard.edu/diseases-and-conditions/influenza-how-to-prevent-and-treat-a-serious-infection. Accessed 5 Apr 2020.
2. Centers for Disease Control and Preventions site. Influenza (flu). Types of Influenza viruses. Updated 18 Nov 2019. https://www.cdc.gov/flu/about/viruses/types.htm. Accessed 5 Apr 2020.
3. Ray ML, Bryan MW, Ruden TM, et al. Effect of sodium in a rehydration beverage when consumed as a fluid or meal. J Appl Physiol. 1998;85(4):1329–36.
4. Nantz MP, Rowe CA, Muller CE, et al. Supplementation with aged garlic extract improves both NK and γδ-T cell function and reduces the severity of cold and flu symptoms: a randomized, double-blind, placebo-controlled nutrition intervention. Clin Nutr. 2012;31(3):337–344.
5. Giancoli A. 5 whole grains to keep your family healthy. Academy of Nutrition and Dietetic site. 27 Aug 2018. https://www.eatright.org/food/vitamins-and-supplements/nutrient-rich-foods/five-grains-to-keep-your-family-healthy. Accessed 5 Apr 2020.
6. Carr AC and Maggini S. Vitamin C and immune function. Nutrients. 2017;9(11): 1211.
7. The Institute of Medicine. Dietary reference intakes for vitamin C, vitamin E, selenium, and carotenoids. Washington, (DC): The National Academy Press; 2000: 186–192.
8. Lewis ED, Meydani SN, and Wu D. Regulatory role of vitamin E in the immune system and inflammation. IUBMB Journals. 2019;71:487-494.