Ensuring Immune Protection in the Growing Years

Immunity: protection against infectious disease conferred either by the immune response generated by immunization or previous infection or by other non-immunologic factors hence, Immunity is protection.

Growing years: 1^st year to 12^th year. But in the 1^st year, growth occurs more than at any other time.

Infection: Invasion and multiplication of microbes not normally present within the body. Localized or systemic. Asymptomatic, subclinical or symptomatic. Gut and mouth bacteria; not infections.

Nutrition: the process of nourishing or being nourished; food assimilation, usage for growth and tissue repairs.

Health Indicators for Infection in Under 5s

• Incidence of(death due to)diarrhoea:  Td in <5/T<5.
• Mothers’ knowledge of home therapy for diarrhoea and management of diarrhoea
• Immunization coverage.
• Malaria mortality and morbidity.
• Prevalence of stunting,   weight and wasting.
• <5, infant and perinatal mortality

Why Increased Infections from 6months? (a)

• Around 6 months, infants energy and nutrients need to start to exceed what is provided by breast milk, and complementary foods(CF) are necessary to meet those needs.
• Once there’s a failed introduction of CFs, the growth, development and building

Why Increased Infections from 6months? (b)

• Complementary foods(CF) NOT introduced: Ignorance, poverty and food insecurity.
• CF given inappropriately: growth and development of strong immune system will falter: ignorance, poverty and food insecurity
• Breastfeeding discontinued: ½ or more of energy needs 6-12months, 1/3^rd 12-24months gone.Work pressure, beliefs, sickness or death.

Why Increased Infections from 6months? ( c)

• Increase the number of times that the child is fed: 2–3 meals per day for 6–8 months of age and 3–4 meals per day for 9–23 months, with 1–2 additional snacks as required

Why Increased Infections from 6months? (d)

• Poor personal hygiene, now that baby begins to crawl.
• Poor environmental hygiene. Dirty surfaces
• Poor food handling: storage, cooking, preservation, feeding practices.
• Disappearance of passive immunity(antibodies obtained transplacentally) 6-12months.

Immunity and Immune System

• Innate, or nonspecific: the defense system with which you were born. Protects against all antigens.
• (a) Involves barriers that keep harmful materials from entering the body. The first line of defence is the immune response. Examples:
• Cough reflex
• Enzymes in tears and skin oils
• Mucus, which traps bacteria and small particles/

Innate Immunity

• Skin
• Stomach acid
• (b) in a protein chemical form, called innate humoral immunity. Examples: the body’s complement system, substances called interferon and interleukin-1 (which causes fever).

Acquired Immunity

• If an antigen gets past innate immunity, it is attacked and destroyed by other parts of the immune system.
• Acquired immunity develops with exposure to various antigens. Your immune system builds a defence against that specific antigen.

Passive Immunity

• As a result of antibodies produced in a body other than your own. Examples: antibodies transferred through the placenta from mother.
• Injection of antiserum, which contains antibodies formed by another person or animal, provides immediate protection against an antigen, but may not be long-lasting. Immune serum globulin (for hepatitis exposure) and tetanus antitoxin are examples.

Blood Components

• Include certain types of white blood cells, chemicals and proteins in the blood, such as antibodies, complement proteins, and interferon. Some directly attack foreign substances in the body, and others work together to help the immune system cells.
• B and T Lymphocytes are a type of white blood cells.
• B lymphocytes produce antibodies that attach to a specific antigen and make it easier for the immune cells to destroy the antigen.

• T cells attack antigens directly and help control the immune response. Release chemicals, called cytokines, which control the entire immune response.
• They differentiate between your own body and another, multiply and provide “memory“ cells hence, respond faster and more efficiently to the next exposure. For example, a person who has had or been immunized against chickenpox is immune from getting chickenpox again.

Nutrition and Immunity: Key Immuno Nutrients

1. Vit A: epithelial cells and mucous tissue formation, more in the gut and respiratory system.

• Promotes mucin secretion hence, improves the antigen non-specific immunity function of these tissues.
• Promotes apoptosis of thymocytes and bone marrow cells.
• Regulation of differentiation, maturation and function of innate immunity cells(neutrophils and macrophages).

Key Immuno Nutrients

2. Vit C: supports cellular functions of both innate and adaptive immunity.

• supports epithelial barrier function against pathogens, promotes the oxidant scavenging activity of the skin, thereby protecting against environmental oxidative stress.
• accumulates in phagocytes, like neutrophils, enhancing chemotaxis, phagocytosis, and microbial killing.
• needed for apoptosis and clearance of the spent neutrophils from sites of infection.

Key Immuno Nutrients

3. Zinc: regulates intracellular signalling pathways in adaptive and innate cells.

• Promotes the maturation of B and T cells.
• Influences Intracellular killing of harmful pathogens and production of cytokines.
• Influences RNA transcription, DNA synthesis and cell survival because Zinc defficiency triggers apoptosis.

Key Immuno Nutrients

4. Selenium: regulates reactive oxygen species and redox reaction in all tissues.

• Regulates cellular response in adaptive and innate immune response.
• Elevates antiviral activity by impairing genomic adaptation in viral RNA.

Nutritional and Immunological Benefits of Breastfeeding

• Breastmilk provides all the energy and nutrients that the infant needs for the first months of life, and it continues to provide up to half or more of a child’s nutritional needs during the second half of the first year, and up to one-third during the second year of life.
• Breastmilk promotes sensory and cognitive development, protects the infant against infectious and chronic diseases, reduces infant mortality due to common childhood illnesses such as diarrhoea or pneumonia, and helps for a quicker recovery during illness.

Nutritional and Immunological Benefits of Breastfeeding.

• Term milk is estimated to be approximately 0.9 to 1.2 g/dL for protein, 3.2 to 3.6 g/dL for fat, and 6.7 to 7.8 g/dL for lactose.
• Energy estimates range from 65 to 70 kcal/dL, and are highly correlated with the fat content of human milk. •whey and casein complexes are present.
• The most abundant proteins are casein, α-lactalbumin, lactoferrin, secretory immunoglobulin IgA, lysozyme, and serum albumin.¹
•  Non-protein nitrogen-containing compounds, including urea, uric acid, creatine, creatinine, amino acids, and nucleotides, comprise ~25% of human milk nitrogen.

Nutritional and Immunological Benefits of Breastfeeding

• Micronutrients vary in human milk depending on maternal diet including vitamins A, B1, B2, B6, B12, D, and iodine. Vitamin K is extremely low in human milk .Vitamin D also occurs in low quantity in human milk, particularly with low maternal exposure to sunshine, a circumstance now common in populations worldwide.

Immunological Benefits of Complementary Feeding

• Provides essential nutrients and the gut microbiome while influencing immune development.
• Early microbial colonisers ferment oligosaccharides, influencing the establishment of the microbiome
• Non-digestible oligosaccharides in prebiotic-supplemented formula and human milk oligosaccharides promote commensal immune-modulating bacteria such as Bifidobacterium.
• Incorporating complex, bifidogenic, non-digestible carbohydrates presents an opportunity to feed commensal bacteria and promote balanced concentrations of short chain fatty acids and vitamins that support gut barrier maturation and immunity.

Individual and Family Consequences of Infections

• Stunted growth and development.
• Reduction in the quality of life.
• Lack of quality education
• Economic loss.
• Work pressure and job loss.
• Physical stress.
• Emotional trauma

Societal Consequences of Infections

• Epidemic tendencies and overwhelmed health institutions.
• Social panic.
• Panic buying and inflation.
• Distruption of socioeconomic activities.

Recommendations

• Exclusive breastfeeding for the first 6 months, and intermittently till 2 years.
• Continuous health education for women of reproductive age on home management of diarrhoeal illnesses, immunization and complementary feeding.
• Favourable Government policies on female socioeconomic empowerment, food security and environmental hygiene.

Conclusions

Immune protection of under 5 children in their growing years, is an important aspect of a child’s development that begins right from birth as the mother commences early exclusive breastfeeding with breast milk rich in proteins, vitamins and immunoglobulins, to the smooth transition to a complemetary feeding at 6months, that further establishes the gut microbiota in fighting infections.

CC: Dr Shallom Oni (MBBS, MPH, MBA)