1
Q
Nutrition
A
- the science of food, nutrients, and substances in food, their action, interaction and balance in relation to health and disease
2
Q
Modern Nutrition
A
- understanding the effects of over-nutrition and the optimal levels of nutrients required for health and well-being
3
Q
Essential Nutrient
A
- a chemical required for metabolism but cannot be synthesized or synthesized rapidly enough to meet the needs of an animal for one or more physiological functions
- removing the nutrient causes a deficiency and decline in health
- putting the nutrient back into the diet corrects the problem and health returns
4
Q
Nutritional Deficiency
A
- a nutrient intake consistently falls below the recommended requirement
5
Q
Rickets
A
- vitamin D deficiency
- the failure to absorb fat
- defective bone growth
6
Q
Scurvy
A
- vitamin C deficiency
- defective collagen production
- hemorrhaging
7
Q
Beriberi
A
- vitamin B1 deficiency
- defective energy production
- abnormalities in the nervous system
8
Q
Anemia
A
- vitamin B12 deficiency
- lacking RBC
9
Q
Nutritional Requirement
A
- how much of a nutrient we need to avoid a problem linked to a deficiency or to optimize health or avoid toxic side effects
- ensures optimal health
10
Q
Nutrition Labels
A
- daily value is based on 2000 calorie a day diet
- rule for general population though varies based on age, gender, etc.
- made using daily reference intakes
11
Q
DRI
A
- dietary reference intakes
- refers to a set of reference values for nutrients ( EAR, RAD, TUL, AI )
12
Q
EAR
A
- estimated average requirement
- based on half of the population
- the needs of 50% of the population are led
- midline of the normal distribution
13
Q
RAD
A
- recommended daily allowance
- the needs of about 97% of the population
- focus on the majority of the population
- 2 standard deviations from the EAR
14
Q
TUL
A
- tolerance upper limit
- highest level of continuous daily nutrient intake that causes no risk of adverse effects
- the gap in the distribution which is the healthy nutrient concentration
15
Q
AI
A
- adequate intake
- determined based on intake in healthy people who are assumed to have an adequate nutritional status
- if insufficient scientific evidence for EAR and RDA
16
Q
Components of a Nutritions Diet
A
- adequate; provides enough calories, essential nutrients and fibre
- balanced; making sure you eat nutrient dense foods rather than nutrient poor foods
- moderate; don’t consume excessive calories or eat more of one food group than recommended
- varied; a wide selection of foods to get necessary nutrients
17
Q
Studies of Nutrition
A
- cell culture models; may be inaccurate
- animal models; measures food consumption
- epidemiological cohort studies; prospective vs. retrospective (have the end point and locate the causality)
- intervention studies; randomized control study
18
Q
Macromolecules
A
- carbohydrates
- lipids
- proteins
- consumed in large amounts
19
Q
Micronutrients
A
- vitamins
- minerals
- consumed in small amounts
20
Q
Organic molecules
A
- carbs, fats, proteins, vitamins
21
Q
Function of Water as an Essential Nutrient
A
- solvent
- metabolism
- nutrient transport
- vascular volume
- body temperature
- kidney’s ability to filter the blood; based on salt concentration and osmosis
- hyponatremia; water sodium imbalance from excessive fluid intake, under replacement of sodium
22
Q
Food Analysis
A
- the development application and study of analytical methods for characterizing foods and their constituents
23
Q
Proximate Analysis
A
- approximates six different components in food; moisture, ether extract, ask, nitrogen, crude fibre, and a mathematical derivation of these values
24
Q
Moisture (water content)
A
- difference between wet and dry sample weight; sample is dried in an oven at high temperature to evaporate moisture
- water is weight and is part of the price and must be shipped
- plays role in storage; increased moisture is less stable and more palatable
- dilutes energy and nutrients in food
% moisture = (wet-dry)/wet x 100%
- drying can remove other compounds such as short chain fatty acids and minerals, slight underestimation of dry weight
25
Ether Extract (crude fat)
- estimated amount of fat within sample; dry matter into test tube with ether, and cortex producing a sample separated by fat inside clear solution and precipitate
- clear solution is dried to determine fat content
% crude fat = (weight of ether extract/weight of sample) x 100%
- other things are soluble in extract like chlorophyll, resisins, waxes, overestimating the determination
- gas chromatography corresponding to each fatty acid is more precise
26
Ash
- precipitate residue found in vortex for ether solution is ignited to rid of organic material to calculate mineral content
- affects quality and taste
- high mineral content helps slow bacterial growth
% ash = (weight of ash/ wet weight of sample) x100%
- volatile minerals may be lost in burning, underestimation
- no information about individual minerals, other precise technologies must be used
27
Nitrogen
- all nitrogen is protein, all protein contains 16% nitrogen assumptions
- digestion of sample by sulfuric acid, converting nitrogen to ammonia, distillation separates ammonia and titration quantifies amount of ammonia
% crude protein = (N in sample x 6.25/wet weight of sample) x100%
- actual range of nitrogen is 13-19% in protein
- other nitrogen sources may be present, over-calculation
28
Crude Fibre
- ether precipitate is boiled in acid, use the reside to be boiled in alkali solution leaving the precipitate of ash + crude fibre
- mimics digestion as fibre is not digestible
% crude fibre = (precipitate weight - ash weight / wet weight of sample) x100%
- mainly is cellulose and lignan
- unable to distinguish fibre components, and crude fibre under estimates dietary fibre (soluble and insoluble fibers) by up to 50%
29
Nitrogen Free Extract (NFE) = Digestible CHO
- estimated starch and sugar content
%NFE = 100 - (%moisture + %crude fat + %ash + %crude protein + %crude fibre)
- NFE accumulates all errors from other components
- gives total digestible CHO but does not distinguish between starch and sugar
30
Dietary Fibre
- non-digestible complex CHO; lacking enzymes required to break is down
- insoluble; remains intact through intestinal tract (cellulose, lignin, hemicellulose)
- soluble; forms gel in solution (pectin, gums, mucilages)
- more accurate fibre analyses complete proximate analysis
- Van Soest method; differentiates insoluble fibers; cellulose and hemicellulose vs. lignin (poorly fermented), fermented fibers produce most energy
- Southgate method; provides info about sugars, starch and fibers, does not differentiate between insoluble fibers
31
Digestive System
- the GI tract (mouth, esophagus, stomach, small intestine, large intestine, caecum, rectum) and associated organs (lover, pancreas, salivary glands, gallbladder)
32
Simple Without Caecum
- humans, pig, cat, dog, etc.; nutrient dense, low fibre diet
- oral cavity; food is chewed with enzymes a-amylase (break down CHO) and lingual lipase (break down fats)
- stomach (cardia, fundus, antrum non-anatomically distinct regions); acidic pH for protein denaturation including certain enzymes and food becomes chyme with gastric juice (electrolytes, HCl, enzymes)
- small intestine (duodenum; enzyme release, jejunum; nutrient absorption, ileum; recapture bile acid); large surface area for absorption, motility controlled by tubular and circular muscles as chyme is neutralized by pancreatic juice
- large intestine; fermentation (produces byproducts) and water absorption with high gut bacteria producing short chain fatty acids for energy and control cholesterol level
33
Simple System With Functional Caecum
- horse, rabbit; lots of dry materials
- fermentation is important and occurs after small intestine
- besides caecum, all other functions are the same
- caecum; large hind guy with bacteria, small chain fatty acids (fibre) provide 70% of energy require, vitamin production
- typical coprophagy eating own dung for nutrients with deficiency
- young eat feces to colonize guts with bacteria
34
Ruminant System
- cattle, sheep; lots of dry plant material
- large four chamber stomach for foregut fermentation
- reticulum; capture nutrients and foreign materials, high in bacteria
- rumen; largest section rich in bacteria, have papillae to increase surface area, where food is broke and stored producing 60-80% energy as SCFA but produces lots of methane gas
- omasum; resorption of water and electrolytes, filters large particles
- abomasum; resembles mono gastric stomach
- rumination, can send food back and fourth to ensure small particles for small intestine
- belching; byproduct of fermentation, degraded CHO into gases and lost as heat
35
Avian System
- birds; rapid digestion
- crop; enlarged off esophagus to store food
- two-chamber stomach; proventriculus (glandular) with gastric enzymes, gizzard (muscular) grind and digest food with rocks and sticks
- ceca; minor site of fermentation, is a functional caecum
- cloaca; where digestive, urinary and reproductive systems meet
36
Digestibility
- measures amount of nutrient or energy extracted by GI tract
- represents combination of nutrient release from billy’s, microbial fermentation and absorption
37
Total Collection Method
- allow animal to adapt to diet, isolate animal for quantitative analyses, measure intake over 3-10days and collect and weigh all feces for proximate analysis
apparent digestibility=(total intake - total feces)/total intake
- hard to measure food intake
- cages for abnormal behavior
38
Indicator Method
- a non-absorbable, unaffected marker is mixed with food and can be easily measure in samples
- e.g. ferric oxide, chronic oxide, silica, lignan
- adapt animal to diet, collect feed and fecal sample and analyze for larger and nutrient of j teresa relative to indicator
apparent digestibility = ((nutrient/marker in feed) - (nutrient/marker in feces))/ nutrient/marker in feed
39
Apparent Difestibility
- underestimates true digestibility
- does not account endogenous losses in GI tract;
- endogenous secretions; epithelial cells as fatty acids are released from dying intestinal cells to feces
- bacterial growth by gut bacteria; nutrient synthesis
- digestive enzymes protein secretion: digestive enzymes appearing in feces
40
True Digestibility
- perform digestibility using a test diet
- switch to diet containing none of the nutrient of interest, analyze feces after test diet is cleared and subtract level of nutrient i. feces of animals fed the zero nutrient diet
- over 50 factors influence digestibility and efficiency; feed intake, particle size, chemical composition, climate, age
41
Calorie
- measure of heat to express the energy content of food
| - 1 food calorie = 4.18 kJ; energy required to raise the temp of 1kg of water by 1 degree celsius
42
BMI
- tool to study body weight and obesity
- witching 20 years, BMI and obesity has greatly increased
- high energy balance = obesity
43
Calorimetry
- measurement of heat production by using heat as an indicator of negus stored in the chemical bonds of foods (C-H bonds)
- dry and weigh sample and place in chamber with oxygen, ignite sample, heat released is absorbed by water and measured so heat of combustion is the gross energy
- overestimates energy, inaccurate to digestion
- fuel values take into account incomplete digestion; CHO 4, Fat 9, Protein 4
44
Heat of Combustion
- total energy released during a chemical reaction. between a hydrocarbon oxygen to release CO2 and H2O and heat
- influenced by chemical structure
- CHO = 2:1 hydrogen:oxygen
- proteins = nitrogen and hydrogen combination is lost in urea (hydrogen loss affects)
- fats = less oxidized than others, have lots of hydrogen available for cleavage and oxidation for energy
- large fatty acid with little oxygen generates more energy; longer chain release more energy, more unsaturated release less energy
45
Heat Increment of Feeding
- thermos effect of food
- energy used for digestion, absorption, distribution and storage of nutrients
- comprises (5-30%) of daily energy usage
46
Net Energy
- supports basal metabolism, physical activity, growth, pregnancy, etc.
- metabolizable energy - HIF
47
Total Energy Expenditure
- BMR; energy being used to maintain heart rate, blood pressure and brain function
- HIF; energy for digestion, absorption, transport and storage of nutrients
- PAEE; varies based on physical activity and exercise habits
- Thermoregulation; energy required for heat homeostasis like shivering or sweating, though is not typically a frequent need as humans usually adapt to temperature
48
BMR
- Basal metabolic rate
- measure; short after waking in post-absorptive state completely relaxed with comfortable temperature
- based on metabolic weight (estimate)
BMR=(metabolically active tissue)x(body weight^0.75) kcal/day
- Harris-Benedict equation slightly more refined; based on sex, physical activity level
- could vary based on body tissue proportions
49
Total Energy Expenditure
- all metabolic processes generate heat
- direct calorimetry; measure heat generated, total heat loss
- indirect calorimetry; energy- releasing reaction in body depend on oxygen use, estimates energy requirements by measuring oxygen consumption, CO2 production and urinary nitrogen loss but cannot account for anaerobic processes (lactic acid production)
50
Respiratory Quotient
- information about energy expenditure and biological substrate being oxidized
RQ=(CO2 produced)/(O2 consumed)
- each macronutrient requires different amount of O2 intake in relation to CO2 produced
- CHO RQ=1, Fat RQ=0.7
- non-protein RQ because protein contributes little to energy metabolism
i’m
51
Cross Over Concept
- depending on exercise intensity, body will use more or less of a fuel
- CHO for high intensity, fat for low intensity
- crossover is where muscle starts to use more CHO than fat to sustain power
- efficiency at using CHO as local energy as it is stored in the muscle unlike
fat
- with training, muscles adapt and begin to safely store fat in muscle tissue
NUTR3210
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