Nutrition, immune function, and infectious disease

Published online: 21 February 2022

Immune system

The human immune system has evolved over time to protect us against pathogenic organisms including bacteria, viruses, parasites, and fungi.  A myriad of different cell types, communication modules and functioning responses make up this complex system, working together to enable it to protect the body from organisms that can make us ill (1).  

Nutrition is one of the many modifiable factors that impact our immune system’s effectiveness (2). Good nutrition not only fuels its function and creates the building blocks needed to produce antibodies, cytokines, receptor cells, it also provides nutrients with specific antibacterial or anti-viral functions such as vitamin D and zinc. A healthy, balanced diet is also important in promoting a diverse gut microbiota, which plays an influential role in immune system regulation (3).

Consequently, those with impaired immune systems are more susceptible to infection, and at increased risk of an infection being severe or even fatal. As we age, the immune system is compromised through immunosenescence, a factor that likely predisposed older people to have more severe cases of infections such as influenza and COVID-19 (1).

Immune competence can also be diminished with obesity through impaired activity of cytotoxic and helper T Cells, B Cells, and natural killer cells. The COVID-19 pandemic has highlighted the increased susceptibility of poorer disease outcomes in those living with obesity compared to healthy weight individuals, possibly due to its inflammatory component. A recent meta-analysis of 22 studies from seven countries in North America, Europe, and Asia, reported that obesity significantly increased the likelihood of presenting with more severe COVID-19 symptoms, requiring hospitalisation, being admitted to an intensive care unit, undergoing invasive mechanical ventilation, and developing acute respiratory distress syndrome compared to patients without obesity (4).

According to data from World Population Prospects, the global population of those aged 65 and over is growing faster than all other age groups (5). Given that worldwide obesity has also tripled since 1975 (6), it is likely we will see an increased prevalence of mortality and morbidity associated with infectious diseases. Nutrition therefore plays an important preventative role in maintaining a healthy immune system throughout life and could also be associated with considerable health service cost savings (7). 


Nutrition, immune function, and infectious disease hosted by the Nutrition Society Scottish Section

Taking place on 4 -5 April 2022 at the Royal Society of Edinburgh, the conference will discuss this area of nutrition research, as experts come together to explore the links between nutrition, immune function, and infectious disease risk.

The two-day event aims to examine the role of macro- and micronutrient intake and nutritional status on immune function and infectious disease susceptibility and take a closer look at the role supplements play in immune response.

Focusing on the role of dietary supplementation and immune function, speakers on day one will discuss the role of glutamine in correcting exercise-induced immunosuppression, as well as the effect energy intake deficit and glutamine metabolism has on immune function and infection. Day two will take a closer look at lessons learnt from chronic fatigue syndrome to better understand the effect of long-covid on nutrition and immunity. 

Organised by The Nutrition Society Scottish Section, the conference welcomes both members and non-members. Students and groups of seven or more can benefit from reduced fees.



  1. Calder PC. (2021). Nutrition and immunity: lessons for COVID-19. Nature.
  2. Richardson and Lovegrove (2020). Nutritional status of micronutrients as a possible and modifiable risk factor for COVID-19: a UK perspective. British Journal of Nutrition.  
  3. Calder PC. (2020). Nutrition, immunity and COVID-19. BMJ Nutrition, Prevention & Health.
  4. Zhang X, Lewis AM, Moley JR, Brestoff JR (2021). A systematic review and meta‐analysis of obesity and COVID‐19 outcomes. Sci Rep.11:7193.
  5. 2019 Revision of World Population Prospects. United Nations. 
  6. World Health Organisation (WHO). 2021. Obesity and Overweight.