Nutritional Immunity, Role of Nutrients in Immunity

1. Nutritional Immunology
-Nutritional immunodeficiency
ROSHINA RABAIL
LECTURER, GOVERNMENT COLLEGE WOMEN UNIVERSITY, FAISALABAD, PAKIS TAN.
M.PHIL HUMAN NUTRITION AND DIETETICS
FORMER DIETITIAN CMH OKARA CANTT. & SHIFA INT. HOSPITAL ISLAMABAD
ROSHINA RABAIL 1

2. Nutritional immunology, the study of the relationship between nutrition and
immunity, was a discipline that arose largely during the early 20th century.
Undernutrition cause immunodeficiency and the compromise in immune function due
to undernutrition is often referred to as ‘nutritional immunodeficiency’.
A range of host factors, which include non-specific barriers that prevent entry of
pathogens and innate and acquired immune mechanisms, operate in the human body
to prevent infections.
The interactions between nutrition and the immune system have clinical, practical, and
public health importance
The growth in our understanding of this interaction and synergism has resulted in the
development of nutrition interventions and strategies to address public health issues
such as the reduction of maternal and child morbidity and mortality in developing
countries.
ROSHINA RABAIL 2
Nutritional Immunodeficiency

3. Undernutrition compromises several of Immune functions, increasing the
susceptibility to the infective agent.
Moreover, deficiencies of micronutrients like vitamins and minerals tend to
specifically affect one or more components of the immune mechanisms and
increase the risk of infections.
Deficiencies in vitamin A and Zinc are good examples of micronutrients that
compromise immune function in man.
It is important to know that micronutrient deficiencies are a much bigger public
health problem, affecting nearly 2 billion people worldwide.
ROSHINA RABAIL 3
Under Nutrition and Immunity

4. Over nutrition states like obesity may also compromise immune function and increase
the risk of infections.
The relationship between nutrition and infection in man is not always synergistic.
In some instances, some nutrients like iron show an antagonistic interaction with
infection. This paradoxical situation is exemplified by a nutrient deficiency favouring the
host and providing a protective advantage to the host.
The nutrient that typifies this type of response is iron. Iron deficiency favours the host
by restricting the availability of this specific nutrient to the invasive pathogen.
Malaria is an example where supplementation with iron increases malarial infection. In
Zanzibar increased hospitalization and excess mortality were observed in children who
were receiving iron supplements.
ROSHINA RABAIL 4
Over Nutrition and Immunity

5. Role of Nutrients in Immune Function
The energy needs of the body may be increased during an infection to compensate for the increased
energy demands due to fever and shivering associated with the infection.
Protein requirements are increased during infections as more protein is required for the synthesis of
cytokines and acute-phase proteins and the proliferation of immune cells.
Some amino acids, like arginine, glutamine, methionine and cysteine, and free fatty acids have an
important role in the normal functioning of the immune system.
Vitamin A plays an important role in host defence mechanisms, including both cell-mediated
immunity and humoral immune mechanisms.
Both iron deficiency states and excess iron can exert adverse effects on the body’s response to an
infection.
Zinc plays an important role in the body’s immune function.
Other nutrients that influence the immune system are trace minerals like selenium and copper and
antioxidant vitamins like vitamin C and vitamin E.
Several nutrients influence the cytokine functions of the body.
ROSHINA RABAIL 5

6. ROSHINA RABAIL 6

7. Metabolic changes in the host during an infection.
Macronutrient metabolism Changes during infection
Protein metabolism Breakdown of muscle protein; Temporary increase in amino acid pool and increased urea
synthesis. With prolonged infections, amino acid levels fall; Decrease in branched-chain (i.e.
gluconeogenic) amino acids like valine and alanine; Increased nitrogen loss and negative
nitrogen balance; Increased synthesis of acute-phase proteins and metal-binding proteins;
Reduced synthesis of albumin; Increased gluconeogenesis (amino acids used as fuel source)
Carbohydrate metabolism Increased glucose oxidation; Increased glucose and insulin levels; Functional insulin resistance
in muscle
Lipid metabolism Levels of free fatty acids and triacylglycerols may increase or decrease; Some infections
characterized by increased triacylglycerol levels; Reduced production and utilization of ketone
bodies like
hydroxybutyrate and acetoacetate; Tendency to fatty liver in severe infections
Vitamin metabolism Fall in circulating levels of vitamin A, vitamin C and riboflavin
Mineral metabolism Decrease in circulating levels of plasma iron and zinc; Reduced gastrointestinal absorption of
iron
Removal of iron to liver cells; Uptake of zinc by reticulo-endothelial cells; Increase in circulating
copper levels resulting from increased; synthesis of copper-carrying protein; Increased loss of
magnesium, potassium, phosphorus and sulfur in urine and other body fluids
Hormonal changes Increase in insulin; Increase in glucocorticoids; loss of diurnal changes in glucocorticoids;
Increase in glucagon and growth hormoneROSHINA RABAIL 7

8. The recognition of specific vitamins and developments in immunology made it
possible to study the effects of single or multiple vitamin deficiencies/over
intake upon immune function.
Specific influences of nutrients on immune function are summarized for
generic nutritional depletion, vitamins, trace elements and minerals and
antioxidants.
ROSHINA RABAIL 8
The Role of Vitamins in Immunity

9. Vitamin A
When first discovered in early 20th century, it was called ‘anti-infection vitamin’
because of its ability to prevent death due to infections in laboratory animals.
Deficiency impairs mucosal function in the respiratory, gastrointestinal and
genitourinary tracts.
Deficiency affects production of immune cells as it impairs the development of
primary lymphoid organs and their cellular proliferation.
Deficiency reduces leukocytes number, lymphoid tissue weight, complement, T-cell
function, tumor resistance, NK cell number, Ag-specific IgG and IgE, Th2 cytokines
Deficiency increases IFN-ɣ synthesis
Supplementation increases lymphocytes proliferation, tumor resistance, graft
rejection, and cytotoxic T-cell activity
Excess intake has adjuvant effects, possibly by apoptosis inhibition
ROSHINA RABAIL 9
The Role of Vitamins in Immunity

10. ROSHINA RABAIL 10
Supplementation increases
lymphocytes proliferation, tumor
resistance, graft rejection, and
cytotoxic T-cell activity
Excess intake has adjuvant effects,
possibly by apoptosis inhibition
The Role of Vitamins
in Immunity

11. Vitamin B complex
Pyridoxine (B6) deficiency reduces lymphocytes number and proliferative response,
lymphoid tissue weight, graft rejection, IL-2 production, DTH response, Ab response
Pyridoxine supplementation protects against UV-B induced immunosuppression
B12 deficiency depresses phagocyte functions, DTH response, T-cells proliferation
Biotin (H) deficiency reduces thymic weight, Ab response, lymphocytes proliferation
Pantothenic acid deficiency reduces Ab responses
Thiamin (B1) deficiency reduces thymic weight, Ab response, PMN motility
Riboflavin (B2) deficiency decreases Ab responses, thymic weight, circulating
lymphocytes number
ROSHINA RABAIL 11
The Role of Vitamins in Immunity

12. Vitamin C
Deficiency lowers phagocytes activity, tumor resistance, DTH reactions, graft rejection, and
slows wound repair
Vit C Increase circulating immunoglobulin levels.
Antioxidant function protects phagocytes
Vitamin D
Stimulates monocytes and macrophages development and phagocytosis
Selectively suppresses Th1, and not Th2 or CD8+ cells activity
Vitamin E
Deficiency reduces lymphocytes proliferation, phagocytes functions, tumor resistance
Supplementation increases lymphocytes proliferation, Ab levels, DTH reaction, IL-2
production, phagocytosis, Th1 activity, and reduces PGE2 synthesis
ROSHINA RABAIL 12
The Role of Vitamins in Immunity

13. The Role of Trace Elements and Minerals in Immunity
Copper
Deficiency reduces antibody production, phagocytic activity, IL-2 production, T-cell
proliferation, and neutrphils respiratory burst and anti-Candida activity in rodents;
decreases T-cells proliferation in humans; increases B-cell number
Involved in complement function, cell membrane integrity, Cu-Zn superoxide
dismutase (SOD), Ig structure
Magnesium
Deficiency increases thymic cellularity, eosinophils, IL-1, IL-6, TNF-α and histamine
levels; reduces acute-phase protein and complement activity
Influences cytotoxicity of CTL through interactions with ATP and adhesion molecules
Component of metalloenzymes
ROSHINA RABAIL 13

14. Iron
Infection onset are reported to change iron distribution in body by shifting
extracellular iron to the intracellular compartment because iron is an essential
element for the growth and replication of microorganisms; hence this natural
strategy deprive invading pathogens of an essential nutrient and has also been
termed as ‘nutritional immunity’.
Iron deficiency and iron overload both results in increased susceptibility to
infections.
Iron deficiency affects the innate immune function. Intracellular killing of
pathogens is markedly impaired in iron deficiency.
ROSHINA RABAIL 14
The Role of Trace Elements and Minerals in Immunity

15. Iron Deficiency reduces DTH-Delayed Type Hypersensitivity reaction, graft
rejection, and cytotoxic activity of phagocytes
Low plasma iron selectively inhibits proliferation of Th1, and not Th2.
High plasma iron interferes with IFN-ɣ
Important in the formation of reactive oxygen and radicals during respiratory
burst
Component of metalloenzymes
Selenium
Deficiency reduces thymic cellularity, eosinophils, cytokines synthesis,
cell-mediated cytotoxicity, lymphocytes proliferation
A component of antioxidant enzyme glutathione peroxidase
ROSHINA RABAIL 15
The Role of Trace Elements and Minerals in Immunity

16. Zinc
Zinc also shows a shift from the circulation into the
intracellular compartment during an infection but this shift
is might be related to the role of zinc metalloenzymes in
DNA transcription and RNA translation in lymphocytes.
Zinc deficiency therefore result in diminished lymphocyte
proliferation and impaired host defense.
Defects in cell-mediated immunity and increased
susceptibility to infections have been seen in patients with
zinc deficiency
Important for thymocyte development, T-cell function, and
thymic integrity;
component of many proteins including transcription
factors, SOD, MHC I
Deficiency causes reduction in T-cell development, thymic
hormone release, T-cell function
ROSHINA RABAIL 16
The Role of Trace Elements and Minerals in Immunity

17. ROSHINA RABAIL 17

18. References
 Understanding the immune system, how it works; U.S. Department of Health and Human
Services, National Institutes of Health(NIH), National Institute of Allergy and Infectious Diseases,
National Cancer Institute.
Nutrition, Immunity, Infection; by Prakash Shetty
Handbook of Nutrition and Immunity by Eric Gershwin
ROSHINA RABAIL 18