The immune system protects us from disease caused by bacteria, viruses and toxins, and helps remove foreign bodies and malignant cells from our system. In addition, the immune system is responsible for down-regulating immune responses against external harmless triggers such as food, or against the bodies’ own tissue. Failure to do so can result in the development of allergy or autoimmune disorders. The immune system is not fully developed at birth, but matures over the first few years of life. Early life is therefore a key phase for training an infant’s immune system.1
Immunity starts in the gut
70-80% of our immune cells live in the gastrointestinal tract2 along with the 100 trillion gut bacteria that make up the gut microbiota. The gut is a major entrance for pathogens, toxins and allergens and one of the major roles of the immune system in the gastrointestinal tract is to distinguish between harmless antigens, such as food, and health hazards. The development of a healthy immune system is therefore reliant on the establishment of a healthy gut microbiota in early life, which is directly linked to nutrition.3,4
Effect of nutrition in early life on immune development
Receiving the right nutrition during early life can positively impact the gut microbiota and therefore the developing immune system. It leads to immediate benefits in terms of supporting the healthy growth and development of an individual but also over the long term by preventing and managing disease. In fact, studies show that for instance allergies may be prevented by making the right nutritional choices during the first 1000 days of life.
Human milk is the best source of nutrition for infants during the first six months of life, containing all the nutrients necessary for healthy growth and development.5 Human milk also contains numerous immune factors (e.g. immune cells, maternal antibodies, prebiotics, nucleotides, fatty acids and carbohydrates) that work synergistically to optimise the immune system and protect the infant from infections and contribute to the prevention of allergic diseases.6,7,8,9,10,11,12 These immune factors also help reduce the risk of non-communicable diseases in later life such as inflammatory bowel disease, obesity and type-II diabetes.13
For mothers who are unable to breastfeed, infant formula is a reliable alternative. Increasing evidence suggests that specific ingredients such as pre-, pro- and synbiotics can positively influence the development of a healthy immune system.14,15,16,17