As we are still dealing with a global pandemic and are now in the midst of cold and flu season, there is no better time to be proactive with your health. We know that comorbidities, such as obesity, diabetes, and heart disease worsen outcomes of viral illnesses. In addition to these comorbid conditions, here are other factors that also affect immunity:

• Sleep and Melatonin- One of the most important factors in improving immune resilience against respiratory infections is to ensure you are getting adequate, quality sleep. Low concentrations of melatonin can impair sleep as well as impact immunity. In addition to melatonin’s ability to enhance sleep quality, melatonin’s antioxidant and anti-inflammatory effects also play a role in optimizing immune function. Recent research showed that mice exposed to RSV (respiratory syncytial virus) were protected against RSV-induced inflammatory lung damage. Melatonin decreased oxidative stress and the production of pro-inflammatory cytokines.
  • Aim for 8-9 hours of sleep per night and consider taking 2-5 mg melatonin approx. 60 minutes prior to bedtime.

• Nutrients- We are overfed yet undernourished in America. These are the most important nutrients for respiratory health:
  • Zinc– Immune cells are dependent on zinc for their development and maintenance. Zinc has been shown to reduce the duration of the common cold. Zinc rich food sources include pumpkin seeds, legumes, and oysters. Zinc picolinate is the best form of supplemental zinc.
  • Vitamin A– Vitamin A is involved in the function of immune cells such as neutrophils, natural killer cells, monocytes, and T and B lymphocytes. A rich dietary source of vitamin A is liver. Other sources are foods rich in beta-carotene, such as green leafy vegetables (spinach!), carrots and cantaloupe. Your body converts beta-carotene into vitamin A.
  • Green tea- Green tea catechins have been shown to decrease the incidence of upper respiratory tract infections by about 50%. My favorite form of green tea is matcha. See here for my Matcha Green Tea Smoothie recipe.
  • Vitamin D– Vitamin D is critical for proper upper respiratory function. A large meta analysis concluded that individuals taking a regular vitamin D supplement had a lower likelihood of developing acute respiratory tract infections. Vitamin D may also reduce the risk of pro-inflammatory cytokine storms that are associated with worse outcomes in many viral infections. Ask your doctor to test your vitamin D to help determine the best dose for you. Goal level is between 60-80.
  • Vitamin C– Vitamin C can shorten the duration of respiratory tract infections. It also is associated with a significant reduction (45-91% reduction) in the incidence of the common cold. Vitamin C rich food sources include citrus, broccoli, bell peppers, and kiwis.
  • NAC (N-Acetyl Cysteine)– NAC is an antioxidant that is a precursor to glutathione. Glutathione has been found to be low in individuals who have serious outcomes of viral infections. NAC is also a mucolytic, meaning it helps break up mucus production in the respiratory tract. This study showed that individuals taking 1200 mg NAC daily through cold and flu season had fewer flu-like episodes and reduction of symptoms and severity of illness.

• Gut Health– Dysbiosis (or an imbalance of gut bacteria) can be due to a diet low in fiber and high in sugar, antibiotic use, and stress. Dysbiosis is associated with a greater incidence of pro-inflammatory cytokine storm and worsened outcomes of viral infections. After all, about 80% of our immune system is located in the gut.
  • Look for a probiotic with Bifidobacterium in it. Bifidobacterium lactis in particular is associated with improved immune function.
  • Eat fermented foods daily to diversify your gut bacteria- sauerkraut, kimchi, kombucha, plain yogurt.
  • Eat prebiotic rich foods to encourage the growth of healthy gut bacteria in the large intestine. Prebiotics are food for your probiotics. Prebiotic rich foods include Jerusalem artichokes , onions, garlic, leeks, jicama, and asparagus.

I hope you feel empowered with the above information to hopefully prevent viral infections this winter. If you do get sick, optimizing the above factors will most likely improve your outcomes.