Nutrition & immunity Flashcards
immune system
A collection of cells and molecules that protect the body against infection, malignancy, and damaged cells
immunity
reactions by an animal body to foreign
substances such as microbes and various macro molecules
innate immunity
Non-specific immunity due to physical and chemical barrier
acquired (adaptive) immunity
Specific immunity- protection by production of antibodies which are directed against specific antigen
what are the 3 lines of defense in immunity?
- first line of defense (nonspecific)
Skin, ciliated cells, mucus membranes – act as barriers and traps - second line of defense (nonspecific)
- increased body temperature (fever) to create
conditions unsuitable for pathogen growth
- blood brings white blood cells called macrophages
engulf and kill pathogens - third line of defense (specific)
- Macrophages identify the invaders
- Helper T cell calls for help
- B cell tags the invaders with antibodies
- Killer T cells destroy the invader
- Memory T and B cells remember
the invaders
what is the difference between innate & adaptive immunity?
innate immunity:
- Physical and chemical barriers
- Phagocytes (Neutrophils & macrophages)
* Inflammatory process.
* 1st and 2nd line of defense
adaptive immunity:
- Specific towards particular antigen and enhanced with
repeated exposure
- 3rd line of defense
passive immunity
- effects are short-term
- newborn: passive transfer of immunity
- colostrum!! (made last 4-6 weeks of gestation)
natural-maternal immunity
antibodies are introduced into the body (not a result of immune system response)
example: mother transfers her immunity to infant
during breast-feeding; from the hen during egg formation.
artificial- antibody transfer
provision of antiserum (blood serum containing
antibodies) through injections
when is the window of susceptibility for passive immunity?
lasts for 3 weeks to 6 months depending on the
disease and health status of animals
active immunity
body’s own immune response is activated and produces antibodies; occurs when a pathogen or a vaccine is introduced into the body.
- use of weakened pathogens, pathogen parts,
dead pathogens
long-term effect- once you get exposed to pathogen, you retain those antibodies for awhile
what do memory B cells do?
keep antibodies “on file” in case of future exposure to
antigen
what are 2 types of acquired immunity?
- humoral
- Mediated by B lymphocytes
- Acts directly against pathogen-infected cells - cell mediated
- Mediated by T lymphocytes
- Generates specific pathogens that are directed against invading pathogens
nutrition & immunity link
Nutrition interact with animal immune system
- Synergistic effects
- Vicious cycle
Nutritional management goals
- Reduce incidence of disease
- Reduce severity (i.e., magnitude) of disease
- Enhance recovery from immune activation
how is Immune function primarily affected by?
- protein-energy malnutrition
- fatty acids
- antioxidants/micronutrients
overnutrition
excess of macronutrients
causes of protein-energy malnutrition
- Limited food access
- Chronic disease
- Chronic Pain
- Dental/Feeding issues
- Medications
- Severe dieting
what is the most important class of nutrient to consider?
amino acids quantitatively
antioxidants
man-made or natural substances that may prevent or delay some types of cell damage
example:
- amino acids
- vitamins E, C, A
free radicals
- Generated in normal cellular metabolism
- React with enzymes, DNA and damage the tissue
vitamin E
major antioxidant in blood
- Protects against cell damage from free radicals
- Affects both innate and adaptive immunity
immune issues:
- Loss of phagocyte responses
- T and B cell dysfunction
- Difficulty controlling viral infections
vitamin A/ beta-carotene
acts as antioxidant
- Enhances phagocytic activity of macrophages & neutrophils
immune issues:
- Loss of structure/function of cells on mucosal
surfaces
- impaired B & T cells
vitamin C
acts as antioxidant
- Protects cells from reactive oxygen species (ROS)
made by the body to control infections
immune issues:
- Impaired collagen synthesis for barriers
- increased free radical production
vitamin D
- Limits inflammatory response promoted by specific T
cell subtypes - Promotes wound healing
immune issues:
- B cells
decrease immune globulin production & proliferation
- T cells
Decrease in overall proliferation
selenium
- antioxidant effects
- Stimulates general immune responsiveness
immune issues:
- Loss of antioxidant host defense
- Decreased white blood cell and NK cell function
iron
- Aids in T cell development
- Generates some “reactive oxygen species” to kill pathogens
immune issues:
- Reduced phagocyte activity
- Impaired T cell response
- Reduced immunoglobulin levels
minerals
zinc, copper, chromium
influence host defense mechanism:
- Phagocytic activity
- cell-mediated immunity
- humoral immunity
what does over-nutrition & obesity lead to?
- promotes inflammation
- poor wound healing
- increase respiratory, gastrointestinal, & liver infections
