The food you eat provides you with energy and supports your body’s many complex systems, including your immune system. While nutrition always plays a critical role in health, it’s never more important than when you’re sick and have a fever.
A common cold is often accompanied by a fever, the immune system’s response to a pathogen (bacteria, virus, or other microorganism). When the cells of your immune system detect a pathogen in the bloodstream, they release a host of inflammatory chemicals called cytokines. Cytokines, like IL-1, TNF-alpha, and IL-6, trigger your brain’s hypothalamus, the area that acts as your internal thermostat, to raise your core body temperature.1 The body reacts by constricting blood vessels to prevent heat loss and causing you to shiver, generating heat. The resulting fever is all an attempt to make your body a less hospitable environment for the pathogen.
As you can imagine, these processes require a great deal of energy and resources from the body, so focusing on optimal nutrition and hydration during this time is essential.
Key Nutrients That Help You Fight Infections
Your diet may be the most important factor when it comes to helping your immune system ward off infections. Nourishing your body with the right macronutrients, vitamins, minerals, and phytochemicals can directly modulate immune cells, reduce viral replication, and reduce the severity and duration of many infections.
Below are the top compounds to incorporate into your diet to help your body fight infections:
Protein is not only important for muscle growth, it’s also essential for a robust immune system. When you have a fever, your metabolism kicks into high gear, increasing your energy expenditure and protein catabolism, the rate at which proteins are broken down.2 Eating an adequate amount of healthy protein can help replace those that have been lost and fuel your body to continue fighting off the infection.
Antioxidants protect cells from damage against free radicals. Various substances like vitamins, minerals, and phytonutrients can have antioxidant properties. A diet rich in antioxidants can make you less prone to infection and also helps you recover more quickly when you get sick.
Vitamin A comes from two sources: plants and animals. Plants contain carotenoids which are converted to vitamin A in the body, while animal sources (eggs, meat, dairy, etc.) offer preformed vitamin A. Vitamin A protects the epithelium and mucus membranes in the body, which can prevent you from getting sick in the first place. Vitamin A also regulates the activity and production of immune cells, like T helper cells, and various cytokines.3
In addition to protecting the body against oxidation, vitamin C supports the cells that make up your body’s clean-up crew, like neutrophils and macrophages. Vitamin C helps these cells get to the site of infection and increases phagocytosis, which is when a cell surrounds and destroys pathogens.4
Vitamin E is found in higher concentrations in immune cells than in any other cells in the body. It controls how immune cells communicate and divide, reducing your risk of infection and enhancing your immune function when sick.5
Zinc not only decreases oxidative stress but also directly reduces viral replication and can reduce inflammation, which helps you recover from an infection more quickly.8
Flavonoids are a class of thousands of compounds found in fruits, vegetables, and other plants that significantly affect the immune system and our overall health. In addition to antioxidant properties, flavonoids also have anti-bacterial and anti-inflammatory functions in the body. Flavonoids are found in foods like berries, kale, red cabbage, tea, and dark chocolate.6
Stilbenes are another type of polyphenol that directly impacts our immune systems. They work by changing the number of receptors on certain immune cells and increasing the production of other cells to keep our body’s defense system functioning optimally. Stilbenes are found in grapes, berries, peanuts, and dark chocolate.7
Unlike the compounds above that must be obtained from food, glutathione is an antioxidant naturally produced by the body. Our glutathione levels decline with age and can also become depleted through poor nutrition, stress, and environmental toxins. Glutathione supports your body by balancing the immune response, reducing inflammation, and reducing oxidative stress in the body - both essential when trying to fight off an infection. Eating sulfur-rich vegetables like broccoli, brussels sprouts, and cabbage can help boost your glutathione levels.
What to Eat and Drink When You Are Sick
When you’re sick, your body deploys its defenses to fight the infection, which affects your energy and nutrient stores. Eating the proper foods gives your immune system the raw materials it needs to win the fight and help you recover more quickly.
7 Best Foods to Eat When You Are Sick
Here are the top foods to eat when you’re sick:
Your mom was right; chicken soup really is good for a cold! This comfort food is a good source of vitamin A and zinc. It is also packed with healthy protein, fluids, and electrolytes, which can help prevent dehydration due to diarrhea, vomiting, sweating, or fever.
Eating hot soup can also help reduce nasal congestion, thin mucus, and soothe a sore throat. To reduce added energy expenditure, you should prioritize foods that are easy to digest, like soups, when you’re sick. Aim for one to two cups daily when you’re under the weather.
Fruit is one of the best foods you can reach for when you’re sick. Loaded with antioxidants and disease-fighting polyphenols, it can satisfy your sweet tooth and support your immune system. Items like berries or citrus fruits are the best choice when under the weather. Try to get a minimum of two servings per day.
Many people have been warned to avoid dairy products when sick. However, despite the myths, research does not support the idea that dairy affects mucus production.
Good health starts in your gut (this is where most immune cells are located!), so foods containing probiotics, like yogurt, help support your overall immune system. Studies have shown probiotics can not only prevent colds but also help you recover faster when you get one.9
In addition to probiotics, Greek yogurt is also a great source of protein, which gives your body the building blocks it needs to fight off infections.
Ginger is a true superfood for your immune system. It has powerful antiviral and antibacterial properties and can also reduce inflammation.10 If you feel a cold coming on, try incorporating ginger shots or ginger tea into your routine.
While some may suggest drinking ginger ale to aid an upset stomach, the carbonation can worsen gas, bloating, and diarrhea. Focus instead on consuming the more concentrated forms of ginger noted above.
Garlic not only keeps vampires at bay but also wards off viruses and bacteria! Garlic’s antiviral and antibacterial effects can prevent you from getting sick and can speed up your recovery time as well. One study with 146 people found that participants who took a garlic-based supplement had 70% fewer sick days than the placebo group.11
Garlic can also stimulate immune cells like macrophages, lymphocytes, and natural killer (NK) cells, making it easier for your body to fight infections.12 Garlic makes a great addition to any savory dish (especially chicken soup!).
Honey has anti-inflammatory, antimicrobial, and antioxidant effects on the body, making it an ideal food to reach for when you’re sick. Honey is also rich in nutrients like folate, potassium, and zinc, and it’s been shown to support healthy blood glucose levels.13
Dark leafy greens
When you’re sick, it’s more important than ever to get your greens in. Dark leafy greens like kale, arugula, and spinach are great sources of vitamin A and are also loaded with polyphenols and fiber. High-fiber foods are specifically beneficial for gut-associated lymphoid tissues (or GALT), which make up the body’s first line of defense when it comes to fighting off infection.14
What Can You Drink During Fever?
When you’re sick, the beverages you drink can have just as much of an impact on your body as the food you eat. Here are the top choices for what to drink when you’re sick:
Like hot soup, consuming beverages like hot tea can help relieve nasal congestion. Additionally, teas like ginger and turmeric have antiviral, antioxidant, and anti-inflammatory effects on the body.
Green tea is packed with a powerful polyphenol called Epigallocatechin gallate (EGCG). This compound can increase the number of regulatory T cells, which helps to modulate the immune response and reduce inflammation.15
Bone broths contain amino acids like glycine and arginine, which can reduce inflammation. They are also a great source of glucosamine and minerals such as calcium, magnesium, potassium, and phosphorus, which all support overall immune health. In addition to these health benefits, bone broths provide the high-quality protein your body needs when recovering from an illness.
Your body is made up of about 60% water, and your immune system requires you to be well-hydrated to function properly. Water helps you properly absorb immune-boosting nutrients, supports mucus membranes that protect you from pathogens, and is an important component of your lymphatic fluid which removes toxins, bacteria, and viruses.16 The recommended amount of water you should drink daily will vary depending on your weight and activity level, but aim for at least seven eight-ounce glasses.
Hate the taste of plain water? Try drinking coconut water, which is rich in potassium. Choose a brand that does not contain added sugars and is 100% coconut water.
4 Foods You Should Avoid When You Are Sick
Avoiding certain foods and beverages can also help you feel better sooner. When you’re feeling sick, stay away from the following:
Alcohol can dehydrate you, which alters how your immune system functions.
Sodas are high in sugar, which negatively impacts your blood glucose. A rise in blood glucose levels can increase cytokine synthesis and release, creating inflammation. High blood glucose levels also impair your immune cell’s ability to recognize pathogens, making it harder to fight infections.
Like alcohol, caffeine can dehydrate you, decreasing the effectiveness of your immune system. Adequate sleep is important for your immune system to function properly, and caffeine can leave you feeling jittery and unable to rest. Opt for caffeine-free beverages like herbal or decaf teas.
When your body is fighting an infection, it needs all the nutrient support it can get, so focusing on whole foods rich in polyphenols, like fruits and vegetables, is imperative. Many processed foods are low in essential nutrients and contain inflammatory oils, which can exacerbate an infection.
5 Tips to Ease Fever Symptoms and Feel Better
In addition to optimizing your diet when you’re sick, there are other health behaviors you can focus on to get better fast. Below are our top tips on how to ease your symptoms:
Your body requires additional energy when fighting off an infection, so getting plenty of rest can help speed recovery.
When you experience an upset stomach and it leads to vomiting or diarrhea, it is easy to experience dehydration. Focus on staying hydrated by consuming water, fruit juice, coconut water, sports drinks, or broths, as these options will restore fluid loss and correct electrolyte imbalances. If you live with diabetes or prediabetes, be mindful of the sugar levels in these drink options.
Keep the room cool and aerated
When you have a fever, your core body temperature rises. It’s crucial for your body not to overheat, so ensure your space is air-conditioned and comfortable.
It’s normal to have less of an appetite when you’re sick. However, your body typically burns more calories when you have a fever since it needs energy to fight off pathogens. If you do not feel like eating, prioritize hydration with liquid-based food options like chicken soup or smoothies with fruits and veggies.
Over-the-counter medication like acetaminophen and ibuprofen can help reduce your fever and tone down inflammation.
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Topics discussed in this article:
- Bush, L. M. (2023, June 21). Fever. Merck Manuals Professional Edition. https://www.merckmanuals.com/professional/infectious-diseases/biology-of-infectious-disease/fever
- Powanda, M. C., & Beisel, W. R. (2003). Metabolic Effects of Infection on Protein and Energy Status. Journal of Nutrition, 133(1), 322S-327S. https://doi.org/10.1093/jn/133.1.322s
- The Functional Medicine Approach to COVID-19: Virus-Specific Nutraceutical and Botanical Agents. (2022, September 21). The Institute for Functional Medicine. https://www.ifm.org/news-insights/the-functional-medicine-approach-to-covid-19-virus-specific-nutraceutical-and-botanical-agents/
- Carr, A. C., & Maggini, S. (2017). Vitamin C and Immune Function. Nutrients, 9(11), 1211. https://doi.org/10.3390/nu9111211
- Lewis ED, Meydani SN, Wu D. Regulatory role of vitamin E in the immune system and inflammation. IUBMB Life. 2019 Apr;71(4):487-494. doi: 10.1002/iub.1976. Epub 2018 Nov 30. PMID: 30501009; PMCID: PMC7011499.
- Pérez-Cano, F. J., & Castell, M. (2016). Flavonoids, Inflammation and Immune System. Nutrients, 8(10), 659. https://doi.org/10.3390/nu8100659
- Liu, G., Jiang, H., & Fang, J. (2018). Regulation of Immune Function by Polyphenols. Journal of Immunology Research, 2018, 1–8. https://doi.org/10.1155/2018/1264074
- Prasad, A. S. (2014). Zinc is an Antioxidant and Anti-Inflammatory Agent: Its Role in Human Health. Frontiers in Nutrition, 1. https://doi.org/10.3389/fnut.2014.00014
- King, S. R. B., Glanville, J., Sanders, M. E., Fitzgerald, A., & Varley, D. (2014). Effectiveness of probiotics on the duration of illness in healthy children and adults who develop common acute respiratory infectious conditions: a systematic review and meta-analysis. British Journal of Nutrition, 112(1), 41–54. https://doi.org/10.1017/s0007114514000075
- Mashhadi NS, Ghiasvand R, Askari G, Hariri M, Darvishi L, Mofid MR. Anti-oxidative and anti-inflammatory effects of ginger in health and physical activity: review of current evidence. International Journal of Preventive Medicine. 2013 Apr;4(Suppl 1):S36-42. PMID: 23717767; PMCID: PMC3665023.
- Lissiman, E., Bhasale, A., & Cohen, M. (2014). Garlic for the common cold. The Cochrane Library, 2020(9). https://doi.org/10.1002/14651858.cd006206.pub4