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63 Cards in this Set
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Eastern diet is rich in phyto-estrogens and is low fat*
Phyto-estrogens are: - naturally occurring hormone-like compounds found in plant foods - structural similarity to the human female hormone 17-β estradiol - can bind to estrogen receptors and act as estrogen agonists and antagonists The hypothesis is that phyto-estrogens have a protective effect against cancer due to their similarity in structure to estrogens (first postulated in the 1980s) |
The current hypothesis which explains the association between breast cancer and fat intake, is that the latter influences the secretion and metabolism of various hormones that promote or inhibit the growth of tumors, most notably the estrogens and prostaglandins.
Estrogens at high levels are known to initiate/promote carcinogenesis |
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The fortification of grain products with folic acid to decrease the incidence of common birth defects (______ _____)
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spina bifida
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The iodinization of table salt to prevent _________, a developmental disorder associated with severe neurological and cognitive deficits in children,
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cretinism
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The promotion of diets low in cholesterol to prevent and to manage ___________ disease
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cardiovascular disease.
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Estimates of the amounts of nutrients required to prevent deficiencies and
maintain optimal health and growth It consists of four reference standards for the intake of nutrients designated for specific age group, physiologic state and gender: 1. Tolerable upper limit( UL): 2. Estimated average requirement (EAR): 3. Recommended dietary allowance (RDA): 4. Adequate intake (AI): |
The Dietary Reference Index ( DRI)
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Highest level of daily nutrient intake that is likely to
pose no risk of adverse health effects to almost all individuals in the general population |
Tolerable upper limit( UL):
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Used if a nutrient is essential but the experimental data
are inadequate to calculate an EAR or RDA. The AI is believed to cover the needs of all individuals in a group but uncertainty of the data prevent being able to specify the percentage of individuals cover by this intake |
Adequate intake (AI):
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Average daily intake that is sufficient to meet the nutrient requirements of nearly all (97-98%) the individuals in an age and gender group.
It is normally set at two standard deviations above the EAR. RDA= EAR + 2 standard deviations |
Recommended dietary allowance (RDA)
It is not the minimal requirement; rather is set to provide a margin of safety. |
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Amount of nutrient estimated to meet the nutrient requirement of half of the healthy individuals in an age and gender group.
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Estimated average requirement (EAR)
Useful in estimating actual requirements in groups and individuals |
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nutrient requirements of half of the healthy individuals
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Estimated average requirement (EAR)
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nutrient requirements of nearly all (97-98%) the individuals –
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Recommended dietary allowance (RDA)
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highest level of daily nutrient intake likely to pose no risk of adverse health effects – UL
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Tolerable Upper Limit (UL)
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nutrient is essential but the experimental data are inadequate to calculate an EAR or RDA -
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Adequate Intake (AI)
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All of the following are measures of what?
Body mass index Biochemical markers Other laboratory tests Clinical symptoms. |
Measuring the state of nutrition
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body weight in relation to height
BMI= weight (Kg)/height (m2) |
Body mass index
Measures the state of nutrition |
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Nitrogen excretion: reliable way of assessing daily protein requirements. The amount of protein oxidized by the body is estimated by measuring nitrogen in urine (80% is urea, the rest in hair, stool, sweat)
Plasma proteins: albumin, transthyretin (prealbumin) and transferrin Vitamins and trace metals |
Biochemical markers:
Measures the state of nutrition |
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Hemoglobin
Electrolytes Iron metabolism Daily fluid intake |
Other laboratory tests:
Measures the state of nutrition |
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__________ is the study of how foods affect the expression of our genes and how individual genetic differences can affect the way we respond to nutrients (and other naturally occurring compounds) in the foods we eat.
The goal is to develop personalized nutrition profiles |
Nutritional Genomics or nutrigenomics,
Factors: - Biological factors - Physiological factors - Disease & drug interactions - Social factors - Energy expenditure |
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All of the following describe this factor:
- Genotype (sex) - Digestion - Absorption - Metabolism - Excretion of nutrients - Age and phase of the life cycle |
Biological factors of nutritional state.
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1. Water
2. Calories (energy) from carbohydrate 3. Calories (energy) from protein 4. Calories (energy) from fat 5. 13 vitamins. a. These typically function as enzyme cofactors, e.g., niacin (precursor of NAD and NADP), riboflavin (precursor of FAD, FMN)…. 6. 16-21 minerals |
Six general classes of nutrients:
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Nutrient needed in large amounts (grams daily).
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Macronutrient
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Nutrient needed in small amounts (mgrams daily).
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Micronutrient
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How many calories are in one gram of:
Carbohydrates (Complex, Simple (starches, fiber, sugars) |
4 kcalories per gram
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How many calories are in one gram of:
Lipids (Saturated, Unsaturated (mono-, poly-) |
9 kcalories per gram
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How many calories are in one gram of:
Proteins |
4 kcalories per gram
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How many calories are in one gram of:
Alcohol |
7 kcalories per gram
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______ __________ _____(BMR) is the energy expenditure required to maintain body function at a complete rest: 50-70%
30% for membrane transport 30% for metabolism 40% temperature, physical activity (and growth ) |
Basal metabolic rate
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______ __________ _________ is the sum of basal metabolic rate, the thermal effect of food and the energy used up in physical activity
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Total energy expenditure
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1. Surface area (affects the heat loss)
2. Age (growth and lean muscle mass) 3. Sex (female/male) 4. Activity level |
Energy expenditure is affected
by four factors |
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Structural components
Speed up chemical reactions Serve as chemical messengers Plasma proteins: osmotic balance, transport of substances in blood, fight infection… |
Protein
Role: Provide 4 kcalories of energy per gram, but the body uses protein for energy only if carbohydrate and fat intake is insufficient. Animal protein: eggs, milk, meat, fish and poultry. Contain all of the essential aa Plant protein: vegetable grains and beans. Lack one or more essential aa |
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________ _______ refers to the relationship between the intake of nitrogen (protein) and its excretion (urea and ammonia)
Equilibrium: losses <-> intake |
Nitrogen balance
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Net increase in body protein
- Growing children - Pregnant women - Convalescing adults |
Positive nitrogen balance
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Net loss in body protein
inadequate protein intake (amount or lack of essential aa) Injury (destruction of tissue) - Trauma, illness, surgery or stress (protein catabolism) |
Negative nitrogen balance
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Recommended protein intake: ____ g/Kg body weight/day
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0.8 g/Kg body weight/day
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The RDA for carbohydrates is set at 130 g/day
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3 classes of carbohydrates
1. Starches whole-grain bread, cereal, pasta, corn 2. Sugars fruits, vegetables, milk, honey, sugar cane (complex carbohydrates) and refined sugars (simple carbohydrates) 3. Fibers: plants |
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Glycemic index times the amount of carbohydrate in a standard serving size of that food
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Glycemic load
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Measures the effects of carbohydrates on blood glucose.
Effect of 50 g of CH in a particular food on blood glucose levels compared to the effect of 50 g of glucose. |
Glycemic index
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Some fibers absorb bile acids (associated with high risk colon cancer at high levels)
Fibers that increase fecal bulk decrease the intraluminal concentrations of carcinogens A shortened fecal transit time decreases the time during which toxins can be synthesized and in which they are in contact with the colon. Fiber fermentation to short-chain fatty acids decreases the interluminal pH, thereby decreasing synthesis of secondary bile acids (which promote the generation of tumors) |
Reasons why fiber prevents colon cancer.
Degradation of fiber by fermentation may release fiber-bound calcium. The increased calcium in the colon may help eliminate the mitogenic advantage that cancer cells have over normal cells in a low-calcium environment. Butyric acid appears to slow the proliferation and differentiation of colon cancer cells. Insoluble fibers such as lignin that resist degradation bind carcinogens, thereby minimizing the chances of interactions with colonic mucosal cells. |
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Energy storage
Thermal insulation Components of biological membranes Signaling molecules Synthesis of prostaglandins, leukotrienes and related compounds |
Role of fats
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Palmitic (C16)
Stearic (C18) Myristic (C14) Lauric (C12) In all animal fats, palm oil, cocoa butter and coconut oil |
Saturated fats
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Monounsaturated: Oleic acid (w-9). In olive oil.
Polyunsaturated: arachidonic and linoleic acid (w-6; in nuts, olives, soybeans); a-linolenic (in plants), eicosaspentaenoic and docosahexaenoic (w-3; in fish) |
Unsaturated fatty acids
Essential fatty acids: linoleic and a-linolenic |
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More than 30% fat is considered unsafe:
- Increase risk heart disease - Obesity - High blood pressure - Diabetes - Cancer: colon, prostate, breast… - Can promote high cholesterol |
The importance of a low-fat diet.
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Cholesterol
Mostly endogenously synthesized; only 10-20% comes from the diet Synthesis is highly regulated (changes in dietary cholesterol have little impact) |
Levels are influenced by:
1. Genetics (ApoE..) 2. Dietary fiber (absorption) 3. Type and amount of dietary fat |
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High omega-3’s result in:
1. Reduced synthesis of VLDL and fatty acids 2. decrease in cholesterol synthesis 3. enhanced activity of LDL receptors 4. increased b-oxidation of fatty acids 5. inhibit formation of arachidonic acid 6. reduce platelet activity (prolong blood clotting) |
The relative amount of w-3 fatty acids with respect to arachidonic acid determines the type of prostaglandines and leukotrienes prevalent in the individual
Negative effects: reduce immunity (IL1-a and b and TNFa) |
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What is undernutrition?
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Below RDA or AI
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What is overnutrition?
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Above UL
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The large intestine absorbs _____-______ fatty acids.
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short-chain fatty acids
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The ______ absorbs:
1. Lipids 2. Monosaccharides 3. Amino acids 4. Small peptides |
The jejunum
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What is basal metabolic rate?
1. Biosynthesis anabolism Chemical work 2. Active transport Osmotic work 3. Muscular contraction Mechanical work |
50-70% of total energy expenditure
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Essential amino acids for children?
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Cysteine
Tyrosine Arginine |
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What is the macromolecule?
130 g/day Set for adults and children alike Minimal amount the brain needs for energy RDA is not normally set this way |
Total amount of carbohydrates needed per day.
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Which is more accurate, glycemic load or glycemic index?
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Glycemic load is more accurate than index.
Takes into account the serving size of food. |
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Can absorb up to 24x their weight in water.
Decrease intracolonic pressure and transit times Decrease sugar uptake - controls sugars Decrease pH Decreases the formation of short-chain fatty acids |
Benefits of cellulose (amongst many)
Hemicellulose: Produces butryic acid Slows the proliferation and differentiation of colon cancer cells |
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Most common form of Protein Energy Malnutrition in the US
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hospitals
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Excess protein intake causes:
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Increased loss of calcium
Obesity |
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Dry, brittle hair
Dermatitis Diarrhea Retarded growth. Problems fighting infection (reduced T-lymphocytes, defects in generation of phagocytic cells and production of immunoglobulins) |
Kwashiorkor
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Inadequate intake of protein with adequate intake of energy.
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Thin, wasted appearance
Individuals are small for their age. Permanent stunt in mental and physical conditions if diet does not change. Problems fighting infection (reduced T-lymphocytes, defects in generation of phagocytic cells and production of immunoglobulins) |
Marasmus
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Inadequate intake of protein and energy.
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Decreased serum proteins and cellular immunity
Delayed wound healing Decreased resistance to infection Increased mortality. |
Protein Energy Malnutrition
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Most common form of Protein Energy Malnutrition in the US = hospitals
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Symptoms
Pellegra like skin eruptions Cerebellar ataxia Gross aminoaciduria |
Hartsnup disease
Mutations in SLC6A19: encodes the B0 AT1 neutral amino acid transporter) Partly responsible for absorption of tryptophan |
Impaired neutral amino acid transport in the:
1. Apical brush border of the small intestine 2. Proximal tubule of the kidney |
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Amino acids are retained within the intestinal lumen, where some are converted by bacteria to indolic compounds that can be toxic to the CNS.
Tubular renal transport is also defective, contributing to gross aminoaciduria. Neutral amino acids are also found in the feces Decrease tryptophan absorption => decrease niacin (NAD, NADP). Some symptoms are similar to niacin deficiency (pellagra-like) |
Hartsnup disease
Treatment: 1. Diet Symptoms in persons with Hartnup disorder quickly respond to nicotinic acid supplementation and they require also other vitamins (B) and tryptophan |
Tryptophan is converted to indole in the intestine that is absorbed converted to 3-hydroxyindole (ie. indican) in the liver and subsequently transported to the kidneys for excretion (ie, indicanuria).
Mental retardation and short stature have been described in a few patients. Malnutrition and a low-protein diet are the primary factors that contribute to morbidity Most patients remain asymptomatic A minority of patients have skin photosensitivity, neurologic and psychiatric symptoms |
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1. Weight loss, anemia, chronic diarrhea, malnutrition.
2. Symptoms associated with multiple fat-soluble vitamin deficiencies: - night blindness (Vit. A) - rickets (vit. D) - gastrointestinal bleeding (vit. K). |
Pancreatic insufficiency
Increased fecal excretion of fat (steatorrhea) with concurrent deficiencies of vitamins (specially fat soluble), minerals, CH and proteins |
Diminished lipase activity
(i.e. chronic pancreatitis due to alcoholism or cystic fibrosis). |
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1. Weight loss, anemia, chronic diarrhea, malnutrition.
2. Symptoms associated with multiple fat-soluble vitamin deficiencies: - night blindness (Vit. A) - rickets (vit. D) - gastrointestinal bleeding (vit. K). |
Bile salt deficiency
Increased fecal excretion of fat (steatorrhea) with concurrent deficiencies of vitamins (specially fat soluble), minerals, CH and proteins |
defective micellarization of fats which is necessary for absorption by small intestinal villi
(i.e. cirrhosis, bacterial overgrowth in the small bowel with destruction of bile salts) |
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1. Weight loss, anemia, chronic diarrhea, malnutrition.
2. Symptoms associated with multiple fat-soluble vitamin deficiencies: - night blindness (Vit. A) - rickets (vit. D) - gastrointestinal bleeding (vit. K). |
Small bowel disease
Increased fecal excretion of fat (steatorrhea) with concurrent deficiencies of vitamins (specially fat soluble), minerals, CH and proteins |
associated with a loss of the villous surface.
Leads to malassimilation of fats, proteins and carbohydrates. |