Stress Can Increase Infection RiskPrint
It’s hard to avoid stress during a global pandemic. The concern is that increased stress can weaken immune functions. Ongoing stress triggers high levels of cortisol, a steroid hormone. Excess cortisol diminishes immune functions, and has been shown to increase disease risk while shortening human lifespans.1-17
A 2019 study found that anticipating stress the next day is associated with elevated cortisol soon after waking up in the morning.18 Human studies demonstrate that specific plant extracts can reduce cortisol levels and inhibit its destructive effects.19-24
A recent poll reports that 45% of Americans feel that their mental health has been negatively impacted due to worry and stress over the novel coronavirus.25 Cortisol is one of the body’s main stress hormones.
During stressful times, the adrenal glands release it as part of the “fight-or-flight” response.26 Necessary for life-or-death situations, cortisol directs a complex series of hormonal and physiological changes that support either fleeing to safety or fighting off the threat.27,28
Cortisol boosts muscle tension, blood sugar, heartbeat, tissue-repair substances, and mental focus. At the same time, cortisol turns down non-urgent processes such as immune functions, along with the digestive and reproductive systems.29 When the stressful threat has passed, cortisol is supposed to return to normal “balanced” levels. When stressors are almost always present, as they have been since the coronavirus outbreak, cortisol remains “turned on.” Its continuing high presence in the blood adversely affects critical functions of the body and brain.30
Danger of Elevated Cortisol
Stress results in a decrease in levels of lymphocytes. These immune cells are used to kill viruses and other invaders.31,32 Lymphocyte counts are often reduced when one is fighting a viral infection.33-35 Even if it’s just for a few days, social isolation and loneliness, both common during the current pandemic, also weaken immunity.36 Older individuals are more susceptible to stress and to stress-induced immune damage.37
Long-term overexposure to excess cortisol disrupts almost all body processes, increasing risk for health problems that include:1-17,38
- Immune impairment,
- Cardiovascular disease,
- Gastrointestinal problems,
- Neurodegeneration, including Alzheimer’s disease, and
- Anxiety, depression, and insomnia.
Most worrisome, chronically elevated cortisol is linked to increased mortality risk. A large study of people over age 65 found that men with high cortisol levels were 63% more likely to die than those with lower levels. Women with elevated cortisol were 82% more likely to die than those with low levels.5 And those with high urinary cortisol had a five-fold increased risk of death from cardiovascular disease.3 Higher cortisol is also associated with shortening of telomeres, the stretches of DNA that cap the ends of chromosomes.39,40 As telomeres shorten, the cells that bear them get closer to the ends of their lives, aging the tissues and organs in which they dwell. It’s impossible to avoid all stress, especially during a pandemic. But scientists have demonstrated that natural compounds can lower excess cortisol levels.
Lychee-Green Tea Blend Lowers Cortisol
Grown in China since the 11th century,41 lychee fruit is rich in polyphenols that promote a variety of biological activities, most notably the ability to reduce inflammation and cortisol levels.19 Most lychee products sold today contain long-chain polyphenols, which are not easily absorbed in the intestinal tract. To overcome this obstacle scientists developed a low molecular size extract derived from lychee fruit and green tea.42 The result is a new compound that is stable and highly absorbable.
Researchers tested this lychee-green tea blend on human monocytes, a type of immune cell. They found that it significantly suppressed inflammatory signaling molecules called cytokines, helping to decrease inflammation.43 This confirmed earlier results from clinical trials that evaluated the lychee-green tea blend’s ability to lower stress and stress-induced cortisol.
Reducing Stress-Induced Cortisol
Researchers randomly assigned 19 sedentary but healthy male volunteers (with an average age of 22) to take either a placebo or 100 mg of the lychee-green tea blend daily for four weeks. They conducted blood tests for cortisol and other inflammatory markers before and after the study, and after exercise, which raises cortisol levels.19
Unlike those in the placebo group, the men taking the blend showed significant decreases in cortisol and the pro-inflammatory cytokines IL-1beta and IL-6. The lychee-green tea extract also reduced the rate of increase of these factors following exercise.19 In another study, 10 healthy men took either a placebo or 100 mg of the lychee-green tea blend twice daily for 10 days before exercising under low-oxygen conditions, to increase stress.20 Exercise increased cortisol substantially in the placebo group. The cortisol increase in the lychee-green tea group was significantly smaller.20
HOW TO MEASURE YOUR STRESS LEVELS
Living under the threat of a pandemic, stress can become so constant that you don’t even notice how stressed you are. A cortisol blood test allows you to find out whether your levels are elevated and by how much. If they’re high, that’s a sign of ongoing stress.
Lifestyle changes like meditation, exercise, and eating a healthy diet can bring this level down. Regular use of safe, plant compounds also lowers elevated cortisol and can prevent the immune-weakening effects of stress. A follow-up cortisol test will show whether your efforts have been successful or need to be intensified.
Effects of Tree Bark Extracts
Scientists have identified two tree bark extracts that deliver similar protection against elevated cortisol. The extracts come from a magnolia species, Magnolia officinalis, and Phellodendron amurense, also known as Amur cork tree. Both have been used in traditional Chinese medicine for centuries and have been shown to have non-sedating anti-anxiety effects.22 In one study, investigators enlisted 56 healthy but moderately stressed individuals. Twice daily, participants were given either a placebo or 250 mg of a mixture containing both bark extracts.23 After four weeks, the bark extract recipients had 18% lower cortisol levels compared to placebo recipients. They also had mood improvements and reduced feelings of stress, depression, anger, and fatigue, all likely related to lowered cortisol.23
Two small, additional studies documented benefits of this bark extract blend:
- One six-week study was conducted on healthy but overweight premenopausal women (aged 20-50) with above-average anxiety. Compared to a placebo, a 250 mg dose of the bark extract combination, given three times a day, significantly decreased anxiety.22
- A second study was conducted on a similar group of women with above-average anxiety, who reported eating more in response to stress. The placebo group had significant weight gain over the six-week study. But weight gain was prevented in the bark extract subjects.24
Elevated cortisol weakens the immune system’s ability to fight infection. Lychee-green tea blend and the bark extract combination have been shown to reduce excessive cortisol secretion in response to stress.
Stress weakens immune functions by raising levels of cortisol. This increases the risks of infections and chronic diseases and shortens lifespans. A lychee-green tea blend provides highly absorbable nutrients that have been shown to lower cortisol in human studies. A combination of two bark extracts from the Magnolia and Phellodendron trees has also been shown, in human trials, to lower cortisol and reduce outward manifestations of stress. These compounds offer one approach to reducing excess cortisol levels, which may counteract some of the harmful effects inflicted by chronic stress.
Content Editor: Matea Kuzmanic
- Duggal NA, Upton J, Phillips AC, et al. NK cell immunesenescence is increased by psychological but not physical stress in older adults associated with raised cortisol and reduced perforin expression. Age (Dordr). 2015 Feb;37(1):9748.
- Noordam R, Gunn DA, Tomlin CC, et al. Cortisol serum levels in familial longevity and perceived age: the Leiden longevity study. Psychoneuroendocrinology. 2012 Oct;37(10):1669-75.
- Vogelzangs N, Beekman AT, Milaneschi Y, et al. Urinary cortisol and six-year risk of all-cause and cardiovascular mortality. J Clin Endocrinol Metab. 2010 Nov;95(11):4959-64.
- Hackett RA, Kivimaki M, Kumari M, et al. Diurnal Cortisol Patterns, Future Diabetes, and Impaired Glucose Metabolism in the Whitehall II Cohort Study. J Clin Endocrinol Metab. 2016 Feb;101(2):619-25.
- Schoorlemmer RM, Peeters GM, van Schoor NM, et al. Relationships between cortisol level, mortality and chronic diseases in older persons. Clin Endocrinol (Oxf). 2009 Dec;71(6):779-86.
- Cohen S, Janicki-Deverts D, Doyle WJ, et al. Chronic stress, glucocorticoid receptor resistance, inflammation, and disease risk. Proc Natl Acad Sci U S A. 2012 Apr 17;109(16):5995-9.
- Notarianni E. Hypercortisolemia and glucocorticoid receptor-signaling insufficiency in Alzheimer’s disease initiation and development. Curr Alzheimer Res. 2013 Sep;10(7):714-31.
- Popp J, Wolfsgruber S, Heuser I, et al. Cerebrospinal fluid cortisol and clinical disease progression in MCI and dementia of Alzheimer’s type. Neurobiol Aging. 2015 Feb;36(2):601-7.
- Toledo JB, Toledo E, Weiner MW, et al. Cardiovascular risk factors, cortisol, and amyloid-beta deposition in Alzheimer’s Disease Neuroimaging Initiative. Alzheimers Dement. 2012 Nov;8(6):483-9.
- Nielsen NR, Kristensen TS, Schnohr P, et al. Perceived stress and cause-specific mortality among men and women: results from a prospective cohort study. Am J Epidemiol. 2008 Sep 1;168(5):481-91; discussion 92-6.
- Carroll BJ. Ageing, stress and the brain. Novartis Found Symp. 2002;242:26-36; discussion -45.
- Wikgren M, Maripuu M, Karlsson T, et al. Short telomeres in depression and the general population are associated with a hypocortisolemic state. Biol Psychiatry. 2012 Feb 15;71(4):294-300.
- Epel ES. Psychological and metabolic stress: a recipe for accelerated cellular aging? Hormones (Athens). 2009 Jan-Mar;8(1):7-22.
- Kyrou I, Tsigos C. Chronic stress, visceral obesity and gonadal dysfunction. Hormones (Athens). 2008 Oct-Dec;7(4):287-93.
- Azuma K, Adachi Y, Hayashi H, et al. Chronic Psychological Stress as a Risk Factor of Osteoporosis. J UOEH. 2015 Dec 1;37(4):245-53.
- Kyrou I, Tsigos C. Stress mechanisms and metabolic complications. Horm Metab Res. 2007 Jun;39(6):430-8.
- Schneiderman N, Ironson G, Siegel SD. Stress and health: psychological, behavioral, and biological determinants. Annu Rev Clin Psychol. 2005;1:607-28.
- Kramer AC, Neubauer AB, Stoffel M, et al. Tomorrow’s gonna suck: Today’s stress anticipation predicts tomorrow’s post-awakening cortisol increase. Psychoneuroendocrinology. 2019 Aug;106:38-46.
- Lee JB, Shin YO, Min YK, et al. The effect of Oligonol intake on cortisol and related cytokines in healthy young men. Nutr Res Pract. 2010 Jun;4(3):203-7.
- Nagasawa J, Sugiyama K, Uchimaru J. Oxidative stress in hypobaric and normobaric hypoxia and antioxidant effect of Oligonol. Japan J Mountain Med. 2010;30:118-24.
- Kalman DS, Feldman S, Feldman R, et al. Effect of a proprietary Magnolia and Phellodendron extract on stress levels in healthy women: a pilot, double-blind, placebo-controlled clinical trial. Nutr J. 2008 Apr 21;7:11.
- Talbott SM, Talbott JA, Pugh M. Effect of Magnolia officinalis and Phellodendron amurense (Relora(R)) on cortisol and psychological mood state in moderately stressed subjects. J Int Soc Sports Nutr. 2013 Aug 7;10(1):37.
- Garrison R, Chambliss WG. Effect of a proprietary Magnolia and Phellodendron extract on weight management: a pilot, double-blind, placebo-controlled clinical trial. Altern Ther Health Med. 2006 Jan-Feb;12(1):50-4.
- Available at: https://www.kff.org/health-reform/issue-brief/the-implications-of-covid-19-for-mental-health-and-substance-use/. Accessed April 30, 2020.
- Available at: https://www.mayoclinic.org/healthy-lifestyle/stress-management/in-depth/stress/art-20046037. Accessed April 30, 2020.
- Available at: https://www.health.harvard.edu/staying-healthy/understanding-the-stress-response. Accessed April 30, 2020.
- Available at: https://www.ncbi.nlm.nih.gov/books/NBK538239/. Accessed April 30, 2020.
- Available at: https://www.ncbi.nlm.nih.gov/books/NBK278995/. Accessed May 3, 2020.
- Yaribeygi H, Panahi Y, Sahraei H, et al. The impact of stress on body function: A review. EXCLI J. 2017;16:1057-72.
- Larosa DF, Orange JS. 1. Lymphocytes. J Allergy Clin Immunol. 2008 Feb;121(2 Suppl):S364-9; quiz S412.
- Available at: https://www.ncbi.nlm.nih.gov/books/NBK8423/. Accessed May 5, 2020.
- Pedersen SF, Ho YC. SARS-CoV-2: a storm is raging. J Clin Invest. 2020 May 1;130(5):2202-5.
- Wang X, Xu W, Hu G, et al. SARS-CoV-2 infects T lymphocytes through its spike protein-mediated membrane fusion. Cell Mol Immunol. 2020 Apr 7:1-3.
- Zhang JJ, Dong X, Cao YY, et al. Clinical characteristics of 140 patients infected with SARS-CoV-2 in Wuhan, China. Allergy. 2020 Feb 19.
- Available at: https://www.apa.org/monitor/2019/05/ce-corner-isolation. Accessed April 30, 2020.
- Available at: https://www.cdc.gov/coronavirus/2019-ncov/daily-life-coping/managing-stress-anxiety.html. Accessed April 29, 2020.
- Available at: https://health.clevelandclinic.org/what-happens-when-your-immune-system-gets-stressed-out/. Accessed April 30, 2020.
- Aulinas A, Ramirez MJ, Barahona MJ, et al. Telomeres and endocrine dysfunction of the adrenal and GH/IGF-1 axes. Clin Endocrinol (Oxf). 2013 Dec;79(6):751-9.
- Tomiyama AJ, O’Donovan A, Lin J, et al. Does cellular aging relate to patterns of allostasis? An examination of basal and stress reactive HPA axis activity and telomere length. Physiol Behav. 2012 Apr 12;106(1):40-5.
- Available at: https://hort.purdue.edu/newcrop/morton/lychee.html. Accessed April 30, 2020.
- Available at: https://www.maypro.com/products/oligonol®. Accessed April 30, 2020.
- Lee N, Shin MS, Kang Y, et al. Oligonol, a lychee fruit-derived low-molecular form of polyphenol mixture, suppresses inflammatory cytokine production from human monocytes. Hum Immunol. 2016 Jun;77(6):512-5.
- Lee J, Shin Y, Murota H. Oligonol supplementation modulates plasma volume and osmolality and sweating after heat load in humans. J Med Food. 2015 May;18(5):578-