ADDRESSING UNDERLYING RISK FACTORS OF RESPIRATORY TRACT INFECTIONS
It is important to note that no supplement, diet or lifestyle modification has been proven to protect against COVID-19 specifically
Respiratory tract infections have a greater annual global disease burden than cancer, heart attacks and strokes. Despite current events, there has been little advice on how individuals can take positive steps to support their health, other than by social distancing, wearing face masks and hand washing to protect from airborne transmission. As we progressively move out of lockdown, I feel it is important to keep people informed of the scientific research relating to viral infections.
Based on studies to date it appears that the most susceptible are those with diabetes, hypertension, cardiovascular disease, the overweight and obese, the elderly and chronic obstructive pulmonary disorder (COPD). 1, 2 Four of these six listed risk categories relate to health issues predominantly influenced by dietary and lifestyle choices. Dietary and lifestyle choices are modifiable. In the UK, these four risk factors are on the increase. Even without a viral pandemic they incur huge cost to society, both financially and emotionally. 3
So how do we move forward? Do we adjust to a ‘new normal’ where we socially distance ourselves from one another until an effective vaccine comes along, whenever that may be? What happens when it mutates? And do we then do the same when the next viral pandemic comes along? It won’t be long. So far this century the world has seen five viral pandemics including Severe Acute Respiratory Syndrome (SARS), Swine Flu, Middle East Respiratory Syndrome (MERS) & Ebola. Whilst transmission of Ebola took place primarily via blood, faeces or vomit; SARS, Swine Flu & MERS were transmitted primarily by airborne droplets, affecting the respiratory tract. Risk factors for these airborne infections also include diabetes, hypertension, cardiovascular disease and obesity.4, 5, 6, 7, 8, 9, 10, 11, 12
It would appear that a plausible strategy, in which we can all take a proactive role, might be to start addressing our underlying health issues. Dietary and lifestyle habits are key. These can be broken down into 4 core elements which are sleep, exercise, relaxation and nutrition.
Sleep allows our bodies and minds to repair and rejuvenate. Studies have shown that cardiovascular risk increases with poor quality and short duration sleep. A 2105 meta-analysis has shown that both excess and lack of sleep increase risk of diabetes with the sweet spot lying between 7-8 hours. Sleeping less than 6 hours has been linked to increased risk of obesity. Various studies have shown a link between poor sleep and hypertension. It has also been shown to be particularly important for initiating effective adaptive immune responses that ultimately produce long-lasting immunological memory. Lack of sleep has been shown to impair immune responses.
Exercise actively protects us from obesity, cardiovascular disease and diabetes. It does this in a multitude of ways from burning fat to decreasing insulin resistance and strengthening our hearts. Exercise is also a fantastic way to reduce stress levels and detoxify the body and mind. Yoga particularly has been shown to improve immune response generally.
The benefits of relaxation result primarily by mitigating stress which research has shown to impair the immune system. For some this might involve a walking amongst nature and for others meditation techniques may be of preference. For many, socialising is an important part of relaxation. Studies have shown social isolation to lead to undesirable health consequences. However, under lockdown we have been advised to maintain social distancing and from the outset and this would appear to have been a logical precautionary measure. Psychoneuroimmunology is a relatively new field of science which has shown how a positive mind set can directly enhance our immune resilience.
Nutrition also plays a foundational role in our overall wellbeing. We evolved to eat whole foods and drink clean water. Many of the products we find in supermarkets today are processed, low in nutrients and high in sugar and contaminants. These foods are pro-inflammatory, paving the way for chronic illnesses such as obesity, diabetes, cardiovascular disease and hypertension. Lack of nutrients can also lead to suboptimal function of the immune system and refined sugars have actually been shown to suppress the immune system for hours after consumption. By prioritising fresh organic whole foods, you will reduce toxin intake, maximise nutrient intake and provide the dietary fibre necessary to support your gut bacteria.
In addition to these core elements, supplements are available to bridge the gap between our existing nutrient status and the optimal levels required to support our many bodily functions, including that of the immune system. Supplements, as the word would suggest, are taken in addition to the existing health strategies employed. Three supplements that have shown promise in the research when it comes to infections. These are:
Since it's discovery, there have been many studies demonstrating that vitamin C may alleviate or prevent infections caused by bacteria, viruses and protozoa. Human clinical trials have shown it can reduce the duration of respiratory tract infections due to the common cold and pneumonia with an intake of 1g every two hours.
Vitamin C status is found to be low in 30% of smokers and the elderly.
Although vitamin C has not been proven to prevent respiratory tract infections, it can reduce the duration.
It also has been shown that vitamin C can reduce the duration of mechanical ventilation in those who are critical ill.
Foods high in vitamin C include broccoli, kale, bell peppers, tomatoes, parsley, oranges and acerola cherries.
A 2019 systemic review and meta-analysis of 24 studies on vitamin D and upper respiratory tract infection has concluded that there is a significant association between vitamin D deficiency and increased risk, severity and duration of upper respiratory tract infection, both viral and bacterial.
Proposed mechanisms include supporting the immune system against respiratory pathogens and inhibition of pro-inflammatory responses. There may also be a role in reducing complications attributed to the cytokine storm.
Vitamin D is produced by our skin when it is exposed to UV sunlight. Over the winter months, vitamin D deficiency affects many of us, especially those of us with darker skin. The safe adult daily upper limit for vitamin D3 supplementation set by the US National Institutes of Health is 4,000iu. Assessment of current vitamin D status is advised prior to supplementation.
Vitamin D containing foods include salmon, salmon, liver, eggs and fortified dairy products.
Several human studies have shown the zinc has both direct and indirect antiviral activity. It plays a fundamental role in mounting an immune response and its homeostasis is critical for sustaining proper immune function. Elderly populations have significantly lower plasma zinc concentrations than younger populations and zinc supplementation has been shown to reduce incidence of infection, inflammatory cytokines and markers of oxidative stress when compared to a placebo group.
There have been multiple studies on zinc deficiency and the effects of zinc supplementation on respiratory tract infections, several of which have shown reduced incidence and duration of symptoms.
Zinc deficiency could be considered a risk factor for impaired immune function and resistance to infection. Furthermore, deficiency is associated with the risk factors for respiratory tract infections, namely obesity, diabetes, cardiovascular disease and hypertension.
The safe adult daily upper limit for zinc supplementation set by the US National Institutes for Health is 40mg.
Foods high in zinc include meat, shellfish, eggs, legumes, nuts and seeds.
The above interventions may be taken as baseline considerations when it comes to supporting your overall health during increased risk of respiratory tract infections. While they may not prevent you from contracting an infection, the evidence base shows that they may significantly reduce the duration and severity of complications in those infected.
If you feel that you could benefit from support with your personal health concerns, do not hesitate to get in touch. I offer a free introductory 30-minute call to talk through your concerns and discuss how we can work together to support your health.
1. Wu, Z. and McGoogan, J., 2020. Characteristics of and Important Lessons From the Coronavirus Disease 2019 (COVID-19) Outbreak in China. JAMA, [online] 323(13), p.1239. Available at: https://jamanetwork.com/journals/jama/fullarticle/2762130
2. Caussy, C., Pattou, F., Wallet, F., Simon, C., Chalopin, S., Telliam, C., Mathieu, D., Subtil, F., Frobert, E., Alligier, M., Delaunay, D., Vanhems, P., Laville, M., Jourdain, M. and Disse, E., 2020. Prevalence of obesity among adult inpatients with COVID-19 in France. The Lancet Diabetes & Endocrinology, [online] 8(7), pp.562-564. Available at: https://www.thelancet.com/journals/landia/article/PIIS2213-8587(20)30160-1/fulltext
3. Bhupathiraju, S. and Hu, F., 2016. Epidemiology of Obesity and Diabetes and Their Cardiovascular Complications. Circulation Research, [online] 118(11), pp.1723-1735. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4887150/
4. Yang, J., Feng, Y., Yuan, M., Yuan, S., Fu, H., Wu, B., Sun, G., Yang, G., Zhang, X., Wang, L., Xu, X., Xu, X. and Chan, J., 2006. Plasma glucose levels and diabetes are independent predictors for mortality and morbidity in patients with SARS. Diabetic Medicine, [online] 23(6), pp.623-628. Available at: https://pubmed.ncbi.nlm.nih.gov/16759303/
5. Yu, C., 2006. Cardiovascular complications of severe acute respiratory syndrome. Postgraduate Medical Journal, [online] 82(964), pp.140-144. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2596695/
6. Chan, J., 2003. Short term outcome and risk factors for adverse clinical outcomes in adults with severe acute respiratory syndrome (SARS). Thorax, [online] 58(8), pp.686-689. Available at: https://thorax.bmj.com/content/58/8/686/
7. Badawi, A. and Ryoo, S., 2016. Prevalence of comorbidities in the Middle East respiratory syndrome coronavirus (MERS-CoV): a systematic review and meta-analysis. International Journal of Infectious Diseases, [online] 49, pp.129-133. Available at: https://www.sciencedirect.com/science/article/pii/S1201971216311006
8. Van Kerkhove, M., Vandemaele, K., Shinde, V., Jaramillo-Gutierrez, G., Koukounari, A., Donnelly, C., Carlino, L., Owen, R., Paterson, B., Pelletier, L., Vachon, J., Gonzalez, C., Hongjie, Y., Zijian, F., Chuang, S., Au, A., Buda, S., Krause, G., Haas, W., Bonmarin, I., Taniguichi, K., Nakajima, K., Shobayashi, T., Takayama, Y., Sunagawa, T., Heraud, J., Orelle, A., Palacios, E., van der Sande, M., Wielders, C., Hunt, D., Cutter, J., Lee, V., Thomas, J., Santa-Olalla, P., Sierra-Moros, M., Hanshaoworakul, W., Ungchusak, K., Pebody, R., Jain, S. and Mounts, A., 2011. Risk Factors for Severe Outcomes following 2009 Influenza A (H1N1) Infection: A Global Pooled Analysis. PLoS Medicine, [online] 8(7), p.e1001053. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3130021/
9. Fajardo-Dolci, G., Gutierrez-Vega, R., Arboleya-Casanova, H., Villalobos, A., Wilson, K., Garcia, S., Sotelo, J., Cordova Villalobos, J. and Diaz-Olavarrieta, C., 2010. Clinical characteristics of fatalities due to influenza A (H1N1) virus in Mexico. Thorax, [online] 65(6), pp.505-509. Available at: https://thorax.bmj.com/content/65/6/505
10. Allard, R., Leclerc, P., Tremblay, C. and Tannenbaum, T., 2010. Diabetes and the Severity of Pandemic Influenza A (H1N1) Infection. Diabetes Care, [online] 33(7), pp.1491-1493. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2890346/
11. Schreter, I., Kristian, P. and Tkacova, R., 2011. Obesity and risk of pneumonia in patients with influenza. European Respiratory Journal, [online] 37(5), pp.1298-1298. Available at: https://erj.ersjournals.com/content/37/5/1298
12. Brandsaeter, B.J., Pillgram, M., Berild, D. et al. Hospitalised patients with suspected 2009 H1N1 Influenza A in a hospital in Norway, July - December 2009. BMC Infect Dis 11, 75 (2011). Available at: https://bmcinfectdis.biomedcentral.com/articles/10.1186/1471-2334-11-75
13. Diekelmann, S., Born, J. The memory function of sleep. Nat Rev Neurosci 11, 114–126 (2010). Available at: https://www.nature.com/articles/nrn2762
14. Wang, C., Bangdiwala, S., Rangarajan, S., Lear, S., AlHabib, K., Mohan, V., Teo, K., Poirier, P., TSE, L., Liu, Z., Rosengren, A., Kumar, R., Lopez-Jaramillo, P., Yusoff, K., Monsef, N., Krishnapillai, V., Ismail, N., Seron, P., Dans, A., Kruger, L., Yeates, K., Leach, L., Yusuf, R., Orlandini, A., Wolyniec, M., Bahonar, A., Mohan, I., Khatib, R., Temizhan, A., Li, W. and Yusuf, S., 2018. Association of estimated sleep duration and naps with mortality and cardiovascular events: a study of 116 632 people from 21 countries. European Heart Journal, [online] 40(20), pp.1620-1629. Available at: https://academic.oup.com/eurheartj/article-abstract/40/20/1620/5229545
15. Domínguez, F., Fuster, V., Fernández-Alvira, J., Fernández-Friera, L., López-Melgar, B., Blanco-Rojo, R., Fernández-Ortiz, A., García-Pavía, P., Sanz, J., Mendiguren, J., Ibañez, B., Bueno, H., Lara-Pezzi, E. and Ordovás, J., 2019. Association of Sleep Duration and Quality With Subclinical Atherosclerosis. Journal of the American College of Cardiology, [online] 73(2), pp.134-144. Available at: https://www.sciencedirect.com/science/article/pii/S0735109718391861
16. Shan, Z., Ma, H., Xie, M., Yan, P., Guo, Y., Bao, W., Rong, Y., Jackson, C., Hu, F. and Liu, L., 2015. Sleep Duration and Risk of Type 2 Diabetes: A Meta-analysis of Prospective Studies. Diabetes Care, [online] 38(3), pp.529-537. Available at: https://care.diabetesjournals.org/content/38/3/529
17. Palagini, L., Maria Bruno, R., Gemignani, A., Baglioni, C., Ghiadoni, L. and Riemann, D., 2013. Sleep Loss and Hypertension: A Systematic Review. Current Pharmaceutical Design, [online] 19(13), pp.2409-2419. Available at: https://pubmed.ncbi.nlm.nih.gov/23173590/
18. Li, M., Yan, S., Jiang, S., Ma, X., Gao, T. and Li, B., 2019. Relationship between sleep duration and hypertension in northeast China: a cross-sectional study. BMJ Open, [online] 9(1), p.e023916. Available at: https://bmjopen.bmj.com/content/9/1/e023916
19. H., Lee, J., Lee, S. et al. The relationship between hypertension and sleep duration: an analysis of the fifth Korea National Health and Nutrition Examination Survey (KNHANES V-3). Clin Hypertens 21, 8 (2015). Available at: https://clinicalhypertension.biomedcentral.com/articles/10.1186/s40885-015-0020-y
20. Pandey, A., Williams, N., Donat, M., Ceide, M., Brimah, P., Ogedegbe, G., McFarlane, S. and Jean-Louis, G., 2013. Linking Sleep to Hypertension: Greater Risk for Blacks. International Journal of Hypertension, [online] 2013, pp.1-7. Available at: https://www.hindawi.com/journals/ijhy/2013/436502/
21. Knutson, K., 2012. Does inadequate sleep play a role in vulnerability to obesity?. American Journal of Human Biology, [online] 24(3), pp.361-371. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3323702/
22. Nursing Standard, 2012. Sleeping too little increases likelihood of obesity, but too much sleep is also bad for you. [online] 26(37), pp.17-17. Available at: https://pubmed.ncbi.nlm.nih.gov/28091302/
23. Bonanno, L., Metro, D., Papa, M., Finzi, G., Maviglia, A., Sottile, F., Corallo, F. and Manasseri, L., 2019. Assessment of sleep and obesity in adults and children. Medicine, [online] 98(46), p.e17642. Available at: https://journals.lww.com/md-journal/fulltext/2019/11150/assessment_of_sleep_and_obesity_in_adults_and.9.aspx
24. Benedict, C., Dimitrov, S., Marshall, L. and Born, J., 2007. Sleep enhances serum interleukin-7 concentrations in humans. Brain, Behavior, and Immunity, [online] 21(8), pp.1058-1062. Available at: https://pubmed.ncbi.nlm.nih.gov/17524612/
25. Brown R, Pang G, Husband AJ, King MG. Suppression of immunity to influenza virus infection in the respiratory tract following sleep disturbance. Reg Immunol. 1989;2(5):321-325. Available at: https://pubmed.ncbi.nlm.nih.gov/2562046/
26. Born J, Lange T, Hansen K, Mölle M, Fehm HL. Effects of sleep and circadian rhythm on human circulating immune cells. J Immunol. 1997;158(9):4454-4464. Available at: https://pubmed.ncbi.nlm.nih.gov/9127011/
27. Campbell, J. and Turner, J., 2018. Debunking the Myth of Exercise-Induced Immune Suppression: Redefining the Impact of Exercise on Immunological Health Across the Lifespan. Frontiers in Immunology, [online] 9. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5911985/
28. Poinsatte K, Smith EE, Torres VO, et al. T and B cell subsets differentially correlate with amyloid deposition and neurocognitive function in patients with amnestic mild cognitive impairment after one year of physical activity. Exerc Immunol Rev. 2019;25:34-49. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6756851/