Why is an individual who starving more susceptible to infectious disease than well nourished?

Starvation weakens the immune system, making individuals more susceptible to infectious diseases for several reasons:

1. Reduced Energy Reserves: Starvation leads to a lack of energy and nutrients, which are crucial for the proper functioning of the immune system. Without adequate energy, immune cells may not have the resources they need to function optimally, making the individual more susceptible to infection.

2. Malnutrition: Starvation causes malnutrition, leading to deficiencies in essential nutrients such as vitamins, minerals, and proteins. These nutrients play vital roles in supporting the immune system, and their deficiency can impair immune cell development and function.

3. Impaired Barrier Function: Starvation can damage the integrity of physical barriers that protect the body from infection, such as the skin and mucosal surfaces. This damage allows pathogens to more easily enter the body and cause infection.

4. Reduced Antibody Production: Starvation affects antibody production, which is essential for the immune system to recognize and fight off infections. Malnourished individuals may have lower levels of antibodies, making them more vulnerable to infections.

5. Altered Immune Cell Function: Starvation can lead to changes in the function of immune cells, including reduced activity of phagocytic cells (which engulf and destroy pathogens) and impaired production of immune signalling molecules. These alterations can compromise the body's ability to fight off infections.

6. Increased Stress Response: Starvation triggers a stress response in the body, which can lead to increased levels of stress hormones such as cortisol. Chronic stress can suppress the immune system and further increase susceptibility to infections.

7. Compromised Gut Health: Starvation can disrupt the gut microbiome, which plays a crucial role in supporting the immune system. An altered gut microbiota can increase the risk of infections and reduce the body's ability to combat pathogens.

8. Poor Healing: Starvation can impair tissue repair and wound healing, making individuals more susceptible to infections at sites of injury or trauma.

9. Increased Inflammation: Starvation can lead to chronic inflammation, which can further weaken the immune system and make individuals more susceptible to infections.

Overall, the weakened immune system caused by starvation makes individuals more vulnerable to a wider range of infectious diseases, including common infections such as respiratory infections, diarrheal diseases, and skin infections.