Post-Infection Effect On Mood And Cognition
Posted in: Articles

“Don’t let your mind bully your body into believing it must carry the burden of its worries.” Astrid Alauda

Fever, chills, cough, nasal congestion, and joint stiffness – these are all well-known symptoms of infection that we may experience in the short-term, whilst our immune system fights off the invading pathogen. However, something we may not always think about when it comes to the impact of an infection on our lives, is the toll it can take on our brain, including our mood and cognition. In fact, recent research found neurological and neuropsychiatric complications of viral infections and many present with a cerebrovascular event (i.e. stroke).1

Going back to basics and looking at the increased need of nutrients during an infection, quite often coupled with a poor appetite or Western diet, can potentially lead to continuing nutrient deficiencies. Neurotransmitters are chemical messengers that transmit messages between nerve cells. Two key neurotransmitters that impact our degree of arousal and engagement, specifically in relation to mood and motivation, are serotonin and dopamine. Collectively, the synthesis of these neurotransmitters requires folate, vitamin B12, vitamin B6, and vitamin C. Methylation, a B vitamin-dependent process, is also essential in the conversion of serotonin to melatonin. When this process is disrupted, it can cause further disruption to our mood and cognitive health. For instance, dysfunctional methylation status has been linked to anxiety,2 bipolar disorder and schizophrenia.3

Poor diet can also result in insufficient levels of key nutrients such as phospholipids, found in eggs, and essential fatty acids found in oily fish. These nutrients are structural components for cells, and key for cell communication. Furthermore, high levels of trans fatty acids in the diet from processed food, margarine, deep fried food etc. have been shown to reduce memory and cognition in adults4 and inhibit production of beneficial omega-3 fatty acids. Omega-3s have anti-inflammatory and cognition enhancing properties,5 possibly due to their regulatory effect on insulin and changes in the connections between nerve cells (neuroplasticity).6

Diet and digestion can also have an impact on neurotransmitter levels through multiple pathways. One study showed 84% of people with gastrointestinal disorders exhibited anxiety and 27% depression.7 Impaired digestion of dietary proteins (particularly gluten from grains and casein from dairy) can produce ‘exorphins’ which are similar in structure to endorphins. Combined with intestinal permeability, these undigested proteins can exert a morphine-like effect in the nervous system, which can disrupt social awareness and behaviour.8 Preliminary research indicates that patients with viral infections may be prone to gut dysbiosis,9 showing the impact an infection can have on mood and cognition could be related to gut health.

The gut is the first point of contact for many pathogens, and so quite often the location of inflammation, which is a natural part of the immune response and vital to managing threats. Inflammatory molecules called cytokines are produced upon detection of an infection and can act upon the brain and drive ‘cytokine-induced sickness behaviours’, where symptoms include fatigue, disinterest in our social environment, and altered mood.10 This is noticeable when we look at nature and notice what animals do when they feel unwell. They will usually retreat into a corner to rest and recuperate. The increased cytokines can induce tryptophan breakdown and thus potentially reducing its availability for making serotonin, which can have significant neurological implications.11 Severe viral infections can induce high levels of pro-inflammatory cytokines, which have been suggested to cause cognitive decline, and increase the risk of subsequently developing neurological disease, in particular Alzheimer’s.12 When viral infections cause lung tissue damage, this could also lead to lack of oxygen (hypoxia) in the brain and further increase brain inflammation, and potentially could cause an increase in brain fog, fatigue, and depression.13 This could be exacerbated by poor blood oxygenation for example due to low folate, B12, iron,14 mouth breathing, and sleep apnea.15

Given the current situation there is also the added impact of isolation and reduced social interaction on mental health. We know from studying Blue Zones that loving and being loved, a sense of belonging, and strong intergenerational connections are at the core of all long-living, healthy communities around the world,16 and this has been put under pressure in the recent pandemic. Research has also found there to be an increased stress response in children from using instant messaging in comparison to in-person speech and over the phone.17 This increase in the stress hormone cortisol could exacerbate low mood and poor cognition.18

Our fast-paced modern society favours a push-through mentality, however, ignoring symptoms can hinder repair and drive further functional imbalances. Remember:

If you listen to your body when it whispers, you won’t have to hear it screamAdapted from Cherokee Proverb

So if you are recovering an infection, whether bacterial or viral, make sure to nourish your nervous system by eating a whole-food, non-processed diet with a wide variety of fruits and vegetables, and consider supplementing with a good methylated multinutrient, fish oils,19 and probiotics. Optimise your sleep and manage stress levels for additional support. Have a go at forest-bathing as getting out in nature will have great benefits on your mental health and immune system.20 We often think that the immune system is unrelated to our mood and cognition, however, as we have shown here, all our body systems are connected and it is important not to forget that.

Got a question?

The brand you can talk to:

We have a team of Nutritionists at the end of our advice line, open to you, for product support and advice (5 days a week). 0121 433 8702 or

Or head to our advice page.

Not registered for an account with BioCare®?

You can register now to receive up to date news, product information and exclusive offers whether you are a consumer, practitioner or retailer.


1. Varatharaj A, Thomas N, Ellul MA, et al. Neurological and neuropsychiatric complications of COVID-19 in 153 patients: a UK-wide surveillance study. The Lancet Psychiatry. 2020;7(10):875-882. doi:10.1016/S2215-0366(20)30287-X

2. Teroganova N, Girshkin L, Suter CM, Green MJ. DNA methylation in peripheral tissue of schizophrenia and bipolar disorder: A systematic review. BMC Genet. 2016;17(1). doi:10.1186/s12863-016-0332-2

3. McCaddon A. Vitamin B12 in neurology and ageing; Clinical and genetic aspects. Biochimie. 2013;95(5):1066-1076. doi:10.1016/j.biochi.2012.11.017

4. Golomb BA, Bui AK. A fat to forget: Trans fat consumption and memory. PLoS One. 2015;10(6). doi:10.1371/journal.pone.0128129

5. Fontani G, Corradeschi F, Felici A, Alfatti F, Migliorini S, Lodi L. Cognitive and physiological effects of Omega-3 polyunsaturated fatty acid supplementation in healthy subjects. Eur J Clin Invest. 2005;35(11):691-699. doi:10.1111/j.1365-2362.2005.01570.x

6. Agrawal R, Gomez-Pinilla F. “Metabolic syndrome” in the brain: Deficiency in omega-3 fatty acid exacerbates dysfunctions in insulin receptor signalling and cognition. J Physiol. 2012;590(10):2485-2499. doi:10.1113/jphysiol.2012.230078

7. Addolorato G, Mirijello A, D’Angelo C, et al. State and trait anxiety and depression in patients affected by gastrointestinal diseases: psychometric evaluation of 1641 patients referred to an internal medicine outpatient setting. Int J Clin Pract. 2008;62(7):1063-1069. doi:10.1111/j.1742-1241.2008.01763.x

8. Reichelt KL, Knivsberg AM. Can the pathophysiology of autism be explained by the nature of the discovered urine peptides? Nutr Neurosci. 2003;6(1):19-28. doi:10.1080/1028415021000042839

9. K X, H C, Y S, et al. [Management of corona virus disease-19 (COVID-19): the Zhejiang experience]. Zhejiang Da Xue Xue Bao Yi Xue Ban. 2020;49(1). doi:10.3785/J.ISSN.1008-9292.2020.02.02

10. McCusker RH, Kelley KW. Immune-neural connections: How the immune system’s response to infectious agents influences behavior. J Exp Biol. 2013;216(1):84-98. doi:10.1242/jeb.073411

11. Davies, Christmas D, Potokar J. A biological pathway linking inflammation and depression: activation of indoleamine 2,3-dioxygenase. Neuropsychiatr Dis Treat. 2011;7:431. doi:10.2147/ndt.s17573

12. Heneka MT, Golenbock D, Latz E, Morgan D, Brown R. Immediate and long-term consequences of COVID-19 infections for the development of neurological disease. Alzheimer’s Res Ther. 2020;12(1). doi:10.1186/s13195-020-00640-3

13. Zhao F, Yang J, Cui R. Effect of Hypoxic Injury in Mood Disorder. Neural Plast. 2017;2017. doi:10.1155/2017/6986983

14. Lanier JB, Park JJ, Callahan RC. Anemia in Older Adults. Vol 98.; 2018. Accessed October 30, 2020.

15. Miller MA, Cappuccio FP. A systematic review of COVID-19 and obstructive sleep apnoea. Sleep Med Rev. 2021;55:101382. doi:10.1016/j.smrv.2020.101382

16. Buettner D, Skemp S. Blue Zones: Lessons From the World’s Longest Lived. Am J Lifestyle Med. 2016;10(5):318-321. doi:10.1177/1559827616637066

17. Seltzer LJ, Prososki AR, Ziegler TE, Pollak SD. Instant messages vs. speech: hormones and why we still need to hear each other. Evol Hum Behav. 2012;33(1):42-45. doi:10.1016/j.evolhumbehav.2011.05.004

18. Cherian K, Schatzberg AF, Keller J. HPA axis in psychotic major depression and schizophrenia spectrum disorders: Cortisol, clinical symptomatology, and cognition. Schizophr Res. 2019;213:72-79. doi:10.1016/j.schres.2019.07.003

19. Kuszewski JC, Howe PRC, Wong RHX. An exploratory analysis of changes in mental wellbeing following curcumin and fish oil supplementation in middle-aged and older adults. Nutrients. 2020;12(10):1-13. doi:10.3390/nu12102902

20. Wen Y, Yan Q, Pan Y, Gu X, Liu Y. Medical empirical research on forest bathing (Shinrin-yoku): A systematic review. Environ Health Prev Med. 2019;24(1). doi:10.1186/s12199-019-0822-8

November 16, 2020
2773 view(s)

Shaping a healthier society.

© 2024 BioCare Ltd. All Rights Reserved. Company No. 01948434