Immunity Boosting Foods

Good nutrition is essential to a strong immune system, which may offer protection from seasonal illness and other health problems. And there are certain foods that must be consumed regularly to build immunity, says Clinical Nutritionist and Dietitian/Certified Diabetic Educator, Razia Ali

- Razia Ali

The immune system, which is integrated into all our physiological systems, protects the body against infections and other external and internal threats by utilising three distinct layers, depending on the nature of the threat: physical (e.g., skin, epithelial lining of the gastrointestinal and respiratory tracts) and biochemical barriers (e.g., secretions, mucus, and gastric acid), numerous different immune cells (e.g., granulocytes, CD4 or CD8 T and B cells), and antibodies (i.e., immunoglobulins).

The first line of defence is innate immunity, which combines physical and biochemical barriers with a non-specific, leukocyte-mediated cellular response to defend against pathogens. If the pathogen manages to avoid these innate defences, a more complex, adaptive, antigen-specific response is triggered, mediated by T and B lymphocytes, which produces antibodies to target and destroy the pathogen. Both systems protect against native cells that may be harmful, such as cancerous or precancerous cells

As humans age, the immune system evolves from the immature and developing immune responses in infants and children, to immune function that is potentially optimal in adolescents and young adults, followed by a gradual decline in immunity (particularly adaptive processes) in older people.

Age-related changes are compounded by certain lifestyle factors (e.g., diet, environmental factors, and oxidative stress) specific to each life stage, that can influence and modify, in some cases suppressing immune function. Accordingly, the risk and severity of infections such as the common cold and influenza (the most common illnesses in humans), pneumonia, and diarrhoeal infections, also vary over a lifetime.