Cold & Flu FAQ: Boost Your Gut Health and Immunity This Season

Keeping yourself and your family healthy during cold and flu season takes effort. Viruses spread quickly through homes, schools, and offices, disrupting routines and leaving everyone feeling run-down. Your body has powerful defenses, though, starting with your gut microbiome.

A balanced gut is your first line of protection, helping you stay resilient and recover faster. 

This FAQ answers your most common questions with practical, evidence-based guidance to help you prevent illness, manage symptoms, and bounce back stronger this season.

How can I tell if I have a cold or the flu?

Both colds and flu are respiratory infections, but each has distinct symptoms. Here’s a general guide:

How long does it take to recover from a cold or flu? 

Most people feel their worst during days 2-7, with symptoms peaking as your body fights the infection. Active symptoms typically subside within 7-14 days, though lingering fatigue and a mild cough are common as your body fully recovers. Everyone's timeline varies depending on their immune system and overall health.

How long should I stay home from work/school?

It depends on the virus/bug. Knowing when you're most likely to spread illness can help protect those around you.

• Colds: You're most contagious during the first 2–3 days of symptoms, but can spread the virus for up to two weeks.
• Flu: You can spread the virus from 1 day before symptoms start and up to 5–7 days after becoming sick. Children and people with weakened immune systems may be contagious for longer.
• Stomach bugs (gastroenteritis): You're most contagious while symptomatic and can remain so for up to 2 weeks after symptoms resolve, especially with norovirus.

Stay home while you're symptomatic and practice good hand hygiene to avoid spreading the cold and flu. 

What's the easiest way to prevent colds and flu?

Support your gut health. Up to 80% of your immune system is in your gut [1], making a balanced microbiome your first line of defense against illness. Focus on a high-fiber diet, fermented foods like yogurt and sauerkraut, and polyphenol-rich foods like berries and dark chocolate to nourish the beneficial bacteria that support your immune system.

Beyond gut health, hand washing is one of the most effective ways to prevent infection. Wash your hands thoroughly with soap and water for at least 20 seconds. Viruses spread when you touch contaminated surfaces and then touch your eyes, nose, or mouth.

Do hand sanitizers help prevent colds and flu? 

Yes, alcohol-based hand sanitizers may help reduce transmission of colds and flu. However, hand washing with soap and water is more effective and better for your microbiome. (Antimicrobial compounds in sanitizers don't distinguish between beneficial and harmful bacteria and may negatively affect your microbiome.) Soap breaks down the surface membranes of bacteria and viruses, while the lathering and scrubbing action creates friction that lifts away dirt, grease, and microbes. We recommend using soap and water at home, and Water Wipes when you're out and about.

If you do use hand sanitizer, do so sparingly and choose alcohol-based options with at least 60% alcohol. Avoid alcohol-free sanitizers containing benzalkonium chloride (BAC), benzethonium chloride (BET), or chloroxylenol (PCMX), as these chemicals have microbiome/health risks.

Will going outside with wet hair or in cold weather make me sick?

No. Colds and flu are caused by viruses, not cold temperatures or wet hair. Though cold weather may make viral transmission more likely for a few reasons. Cold air reduces your nose's ability to fight off viruses at the first point of contact, weakening its natural defense system [2]. Also, when the temps drop, people tend to spend more time indoors in close contact with others, so it’s easier to catch a cold.

Are antibiotics effective for colds or flu?

No. Colds and flu are caused by viruses, and antibiotics only work for bacterial infections. Taking antibiotics for a virus won't help you feel better. And it can:

• Disrupt your gut microbiome
• Contribute to antibiotic-resistance
• Cause unnecessary side effects

When antibiotics might be needed: If you develop a secondary bacterial infection (like bacterial sinusitis, ear infection, or pneumonia), your practitioner may prescribe antibiotics. 

Do cold and flu medicines actually work?

Research is mixed on how well they work. Over-the-counter (OTC) cold remedies like decongestants, pain relievers, and cough suppressants can help with symptoms, but they won't cure your cold and may have side effects, so use them carefully.

We generally recommend avoiding acetaminophen because it can deplete glutathione, particularly in the lungs [3], [4]. Glutathione is your body's most potent antioxidant, protecting cells from damage, supporting immune function, and helping with detoxification. To boost glutathione naturally, focus on sulfur-rich foods like cruciferous veggies, onions, and garlic.

What to know: If you must take acetaminophen, support your glutathione levels by eating sulfur-rich foods like cruciferous vegetables, onions, and garlic. For any OTC medication, check labels and skip anything with FD&C or artificial dye names followed by numbers (like Red 40 or Yellow 5).

Are there any natural remedies that work? 

During cold and flu season, certain supplements may help support your immune system:

Zinc: Supports immune cell function. May reduce cold duration if taken within 24 hours of symptom onset [5]. Take with food to avoid nausea. Don't use zinc nasal sprays (they can damage your sense of smell) [6].

Vitamin C: Helps maintain healthy immune responses. May slightly reduce symptom duration and severity [7]. 

Elderberry: Shows promise for relieving respiratory symptoms [8]. Make your own elderberry syrup to avoid preservatives and excess sugar.

Vitamin D: Many people become deficient in the winter months, and low levels are associated with increased infection risk [9].

Bovine colostrum: May reduce the duration and severity of diarrhea [10]. Avoid it if you have dairy allergies or lactose intolerance. Antimicrobial spices like garlic, ginger, honey, and turmeric.

What foods should I eat when I'm sick?

Focus on nutrient-dense foods that support your gut health and immune function. And make sure you’re getting plenty of liquids. 

• High-fiber whole foods like vegetables, legumes, whole grains
• Fruits and veggies high in vitamin-C, like citrus, berries, and bell peppers
• Zinc-rich foods (shellfish, meat, legumes, pumpkin seeds)  
• Vitamin D sources (fatty fish, egg yolks, fortified foods) 
• Polyphenol-rich foods: berries, nuts, dark chocolate

• Fermented foods: yogurt, kefir, sauerkraut, kimchi, kombucha
• Antimicrobials like garlic, ginger, honey, turmeric, oregano, thyme, cinnamon
• Liquids like water, coconut water, herbal teas, and broth

Immunity tip: To harness raw garlic's power, grate or crush half a clove and let rest 10 minutes to activate allicin, garlic's immune-supporting compound (use ¼ clove for kids and ⅛ for babies). Since cooking diminishes allicin, add raw garlic to eggs, avocado toast, guacamole, soups, garlic bread, or mix with a little honey on a spoon.

Should I take probiotics when I'm sick?

Yes, probiotics can be beneficial during respiratory infections. Our microbiome specialists often recommend Bacillus clausii (a spore probiotic) to reduce the incidence and severity of respiratory symptoms [11], [12]. Some research shows that strains like Lactobacillus plantarum and Lactobacillus paracasei may help prevent acute respiratory infections [13]. People of all ages may benefit from a multi-strain Lactobacillus/Bifidobacterium probiotic to boost immunity. 

Is it best to let a fever run its course? 

Sometimes it’s best to let nature be (see exceptions below). Fever is your body's natural defense against infection. One study found that elevated body temperature enhances the function of T cells, immune cells that seek out and destroy infected cells, suggesting that fever actually helps us fight illness [14].

Here are some tips to stay comfortable during a fever: 

• Lukewarm baths or compresses
• Light clothing and bedding
• Stay hydrated
• Rest in a cool room

Some general guides on when to consult your practitioner for fever: 

• Adults: temperature exceeds 103°F (39.4°C)
• Children: temperature exceeds 104°F (40°C)
• Babies under 3 months: any fever
• All ages: fever lasting more than 3 days

Is there any truth to "starve a fever, feed a cold"?

No, this outdated saying isn't supported by science. Whether you have a cold or the flu, your body needs nutrition and hydration to fight infection and recover. Listen to your body:

If you don't feel like eating:

• Focus on hydration first (broths, teas, water)
• Try easy-to-digest foods (soup, oatmeal, smoothies)
• Eat small amounts throughout the day

If you have an appetite:

• Eat nutritious, whole foods
• Include protein for immune function
• Choose fruits and vegetables for vitamins
• Remember to keep drinking fluids  

Why do I feel worse at night?

Many people notice their symptoms worsen in the evening. Several factors contribute to this:

1. Cortisol levels drop: This natural anti-inflammatory hormone decreases at night, allowing inflammation to increase
2. Lying down: This position can worsen congestion and post-nasal drip
3. Less distraction: You're more aware of discomfort when you're not busy
4. Circadian immune rhythm: Your immune system becomes more active at night

To sleep better:

• Elevate your head with extra pillows
• Use a humidifier
• Take a warm shower before bed
• Stay hydrated
• Keep tissues and water by your bedside

Should I exercise when I'm sick?

Use the neck rule. Light exercise is usually okay if you have symptoms above the neck (runny nose, sneezing). Skip it if you have symptoms below the neck (chest congestion, upset stomach). In these cases, working out can prolong your illness, worsen your symptoms, and weaken your immunity. 

Tip: Wait until you're fever-free for at least 24 hours (without medication) before returning to your exercise routine.

Why am I still tired weeks after a cold or flu?

Post-viral fatigue is common and can last 2–4 weeks or longer after other symptoms resolve. Several factors contribute:

1. Energy depletion: Your immune system used significant energy fighting the infection
2. Nutrient depletion: Illness drains vitamin and mineral stores [15]
3. Sleep disruption: Poor sleep during illness affects recovery [16], [17]
4. Lingering inflammation: Your body is still healing
5. Deconditioning: Rest during illness reduces fitness

To support recovery:

• Prioritize sleep (you may need extra rest for weeks)
• Eat nutrient-dense foods
• Gradually increase activity
• Stay hydrated
• Manage stress

If fatigue is severe or persists beyond a month, see your practitioner.

My cough won't go away. Is this normal?

Post-viral coughs are very common and can persist for 3–8 weeks after other symptoms resolve. This happens because:

• Airways remain inflamed after the infection
• Your cough reflex is sensitized
• Mucus production continues as you heal

See your practitioner if your cough lasts more than 8 weeks, you develop new symptoms like fever or chest pain, you're coughing up blood or colored mucus, or your cough is getting worse.

Boost your resilience 

Colds and flu happen, especially when you've got kids in school or daycare. But healthy daily habits can help you bounce back faster and feel better along the way. 

Prioritize prevention when everyone is well, show yourselves some extra care when you're under the weather, and give yourself time to get back to normal.

A Tiny+ Family Membership supports your loved ones' gut health through life's ups and downs, including recovering from a recent cold or flu.

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