Nutrition and Immunity Flashcards
Adipokines
Energy balance
Ideal BMI: 19-24
25-35kcal/kg
Obese adipose tissue secretes adipokines that contribute to low-level systemic inflammation
Mediate inflammation and insulin resistance
Cytokines increase T-lymphocyte production, which may contribute to risk of autoimmunity and cancer risk in morbidly obese
Obesity and Immune Effects
Immune system cells do not function normally with overweight or elevated cholesterol/triglyceride levels
Positive associations between overweight and cancers of the breast, endometrium, kidney, colon, prostate, and others
Overweight increases risk of cancer recurrence and decreases survival
Protein and Immune Function
Need enough protein for adequate number of amino acids to help immune system increase its numbers
AA make Ab and other components
Protein Energy Malnutrition (PEM)
Marasmas and cachexia- prolonged starvation with decreased calorie/protein intake
Muscle wasting
Emaciated
Kwashiorkor- inadequate consumption of protein; higher intake of carbohydrates
Edema
Hypoalbuminemia
Marasmic Kwashiorkor
Wasting, edema, stunted growth
PEM Effects
Lymphoid and thymus atrophy
Depressed cutaneous response, even with moderate deficiencies
Reduction in mature T lymphocytes
Reduced antibody-producing cells and reduced immunoglobulin (while serum antibody response is preserved, antibody affinity is reduced)
Reduced phagocytosis
Increase in number of bacteria adhering to respiratory cells – risk of respiratory infection
Arginine and Glutamine
Arginine and Glutamine: non-essential amino acids
conditionally essential
Consuming adequate amounts of daily protein consistent with individual needs will assure production of adequate amounts of arginine and glutamine
Synthesized in body under normal conditions, and are essential in critically ill because the body uses them so much and need more intake in order to obtain the optimal levels
In a healthy state, most people can obtain these levels through diet alone, but when critically ill these aren’t always available to the level they need
Arginine
Mechanism in critically ill patients
Increases T cell number and release
T lymphocyte proliferation
Considered appropriate for surgical patients
“Immuno-specialized” enteral formulas is controversial for some patients
In trauma and sepsis, arginine is used to release NO, which contributes to inflammation.
Ammonia controversy: how body detoxifies it and excretes it
Glutamine
Mechanism
Lymphocytes, macrophages, and neutrophils use glutamine
Glutamine appears to enhance antimicrobial activity in neutrophils
Cell proliferation
Antigen presentation
Cytokine production
Helps to prevent atrophy of the gastrointestinal tract smooth muscle for a patient on enteral feeding, cancer, or not consuming a lot of calories
Antioxidants
Vitamin A (Beta carotene)
Vitamin C (Ascorbic acid)
Vitamin E
Selenium
What do they do?
Disarm free radicals: Free Radical Scavengers
Ensure lymphocytes can divide and reproduce
Ensure neutrophils and macrophages can engulf and kill bacteria
Free Radical Scavengers
Free radical scavengers: donate electrons when and then become oxidized and aren’t harmful to body; it is a matter of balance because if over oxidation then can be a problem
Too many free radicals: contribute to inflammation and course to chronic disease; antioxidants through diet can be supportive
Free Radical Cycle
A chemically reactive O2 free radical attacks fatty acid, DNA protein, or cholesterol molecules, which form other free radicals
This initiates a rapid, destructive chain reaction
The result is disabling injury to lipids of cell membranes and cellular proteins, damage to DNA, or oxidation of cholesterol. These changes may initiate steps leading to diseases such as heart disease, cancer, macular degeneration, and others
Antioxidants, such as vitamin E, stop the chain reaction by changing the nature of the free radical
Dietary Reference Intake Recommendations
Vitamin A: 700-900 mcg/day
Vitamin C: 75-90 mg/day; add another 35 mg if a smoker
Vitamin E 15 mg/day
Selenium 55 mcg/day
Vitamin A Mechanism
Beta carotene: known antioxidant
High blood levels of carotenoids reduce risk of several chronic diseases
cell growth regulation
induction of enzymes
Visual pigment
Cell differentiation
Gene regulation
Used in innate immune system for NKC, macrophages, and neutrophils to function properly
Adaptive: plays a role in development of T helper cells and B cells
Someone who has celiac or Chrohn’s disease (GI not completely intact) need increased vitamin A and E because not absorbed as well (fat soluble)
Vitamin A Deficiency
Impairs regeneration of mucosal barriers Epithelial function (differentiation and production)
Decreases function of neutrophils, macrophages, and NK cells
Diminishes antibody-mediated responses
Increases susceptibility to bacterial, viral, and parasitic infections
Vitamin A Sources, Functions, Deficiency, and Toxicity
Fortified milk, carrots, sweet potatoes, spinach, beef liver, bok choy, and apricots
Chief Functions; vision, maintainence of cornea, epithelial cells, mucous membranes, skin, bone, and tooth growth, regulation of gene expression, reproduction, and immunity
Deficiency: night blindness, impaired bone growth and decayed teeth, keratin lumps on the skin, impaired immunity
Toxicity: increased activity of bone dismantling cells causing reduced bone density and pain, liver abnormalities, birth defects
Ascorbic Acid: Mechanism
Vitamin C
Stimulates WBC production
Synthesis of collagen, norepinephrine, carnitine; promotes resistance to infection by increasing antibodies
Enhances phagocyte oxidative burst activity
Enhances T cell and B cell function
Vitamin C Deficiency
Easily destroyed by oxidation and heat
Scurvy
Impaired wound healing; edema; hemorrhages; and weakness in bone, cartilage, teeth, and connective tissues
Vitamin C Sources, Functions, Deficiency, and Toxicity
Sweet red peppers, Brussel sprouts, grapefruit, sweet potato, orange juice, green peppers, broccoili, strawberries, bok choy
Chief Functions: collagen synthesis, antioxidant, restores vitamin E to active form, supports immune system, and boosts iron absorption
Deficiency: scurvy, pinpoint hemorrhages, fatigue, bleeding gums, bruises, bone fragility, joint pain, poor wound healing, frequent infections
Toxicity: nausea, abdominal cramps, diarrhea, rashes, interference with medical interventions/therapies, aggravation of gout or kidney stones
Vitamin E: Mechanism
Primary role = lipid soluble antioxidant
Protects cell membranes from oxidation-first line of defense
Also protects Vitamin A and carotenes from oxidation (work in synergy with each other)
Thought to prevent LDL oxidation and reduce risk of heart disease, but supplemental Vit E hasn’t been found effective
Tocopherols (plants); tocotrienols (whole grains)
Vitamin E Deficiency
Can take years to develop
Effects the neuromuscular, vascular and reproductive systems
Vitamin E Sources, Functions, Deficiencies, and Toxicity
Safflower oil, wheat germ, mayonnaise, canola oil, and sunflower seeds
Chief Functions: antioxidant, protects cell membranes, regulates oxidation reactions, protects polyunsaturated fatty acids
Deficiency: RBC and nerve damage
Toxicity: neuromuscular, vascular, and reproductive systems
Selenium Mechanism
Part of enzyme systems
Antioxidant that works with Vit E
Kills invading pathogens, fungi
Virus removal
Healing
Selenium Deficiency
Uncommon
Deficiency favors formation of pro-inflammatory compounds
Less effective neutrophils
Selenium Food Sources
Brazil nuts Seafood Meats Whole grains Vegetables grown in Se rich soil
Zinc Mechanism
Functions in association with more than 100 enzymes
Thymulin: T-cell differentiation and T and NK cell functions
T lymphocyte development
Zinc Deficiency
Decreased taste acuity, white spots on nails
Growth retardation (protein synthesis, DNA, cell division)
Impaired lymphocyte response and reduced cutaneous reactions (decreased wound healing, skin lesions)
Promotes apoptosis in B and T lymphocytes, hinders function of macrophage, alters the productions and potency of cytokines
Poor thymic development in infants
Zinc Sources, Chief Functions, Deficiencies, and Toxicity
Seafood, enriched cereals, yogurt, pork, beef
Chief Functions: activates many enzymes, associated with hormones, synthesis of genetic material and proteins, transport of vitamin A, taste perception, wound healing, and reproduction
Deficiency: growth retardation, delayed sexual maturation, impaired immune function, hair loss, eye and skin lesions, loss of appetite
Toxicity: loss of appetite, impaired immunity, reduced copper and iron absorption, low HDL cholesterol (risk factor for heart disease)
Vitamin D Mechanism
Mechanism
Liver converts vitamin D to CALCIDIOL
Kidneys convert stored Vit D into CALCITRIOL which is a powerful steroidal hormone
Calcitriol targets more than 2,000 genes and may well be responsible for boosting immune response as well as fighting cancer
Vit D deficiency link to autoimmune disorders
Vitamin D Functions
Down regulates PAMP receptors
Down regulates cancer cell growth and increases apoptosis
Down regulates inflammatory cytokines
Innate immunity: up-regulate antimicrobial peptides in epithelium
Adaptive immunity: stimulate macrophages to produce defensive proteins
Cell growth, differentiation, proliferation activity
Premyeloid WBC and stem cells into macrophages and monocytes
Vitamin D Sources, Functions, Deficiency, Toxicity
Fortified milk, shrimp, sunlight, salmon
Chief Functions: mineralization of bones and teeth via increase absorption from GI tract, withdrawing Ca2+ from bones, and stimulating retention by kidneys
Deficiency: abnormal bone growth resulting in rickets in children, osteomalacia in adults, malformed teeth, and muscle spasms
Toxicity: elevated blood Ca2+, calcification of soft tissues, excessive thrist, headache, nausea, weakness
Fats
Unsaturated vs. Saturated fats Om-3 FA vs. Om-6 FA 1:1 – 1:4 ratio ideal EPA/DHA Important because Om 6 is proinflammatory FA, but once get beyond 1:4, then induces proinflammation
Types of FA: ALA, EPA, DHA
ALA – alpha linoleic acid – Omega 3
Flaxseed
EPA – Eicosapentaenoic acid – Omega 3
Fish Oil
DHA – Docosahexaenoic acid – Omega 3
Fish oil and algea
Types of FA: GLA, OA, and Coconut Oil
GLA – Gamma linoleic acid – Omega 6
borage oil, evening primrose oil, hemp oil, black current seed oil
OA – Oleic acid – Omega 9
Olive Oil
Coconut Oil – Saturated fat –
Medium chain triglyceride-lauric acid
Plant source of saturated fat
Fat Mechanism
High fat diets decrease T lymphocyte function
Trans fat contributes to chronic low grade inflammation
Omega 3 FA (EPA & DHA) increase anti-inflammatory pathways & prostaglandins
Reduction in total fat = increase number of monocytes and T and B lymphocytes
Phytochemicals
Bioactive Food Components:
molecules that influence biological responses, including gene expression
Occur naturally in plants
Mechanism of action not entirely known antioxidant apoptosis cell-cell communication environmental toxin exposure defense
Prebiotics and Probiotics
Prebiotics: non-digestible plant components that are used by the flora for nourishment.
Fructooligosaccharides: onion, asparagus, artichoke, chicory, banana; inulin supplement
Probiotic: “live microbial food ingredient that is beneficial to health”
Examples: Lactobacillus acidophilus LA5, Bifidobacterium lactis Bb12
Bifidobacterium lactis Bb12 enhances intestinal antibody response in formula-fed infants
Prebiotics and Probiotics Functions
Promotes non-immunologic gut barrier (stabilizes gut microflora)
Modulates host response to microbial pathogens
Mediates balance of pro- and anti- inflammatory cytokines in the GI; anti-TNF-a effects
May stimulate immune cell production system wide
Different strains used for different purposes
Lactobacillus rhamnosus GG
70% reduced risk of developing antibiotic-associated diarrhea in children
Prebiotics and Probiotics Sources
Rich sources include: fermented dairy products (kefir, yogurt, buttermilk), miso, tempeh, bean pastes, soy beverages, soy sauce and fermented vegetables like sauerkraut and kimchi, kombucha
Advise clients to look for live active cultures (National Yogurt Association)
Encourage the incorporation of fermented dairy products into overall diet (smoothies, salad dressings, yogurt)
Plain vs. flavored (to avoid added sugar)
