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Introduction to Nutrition

• Nutrition involves how organisms ingest, digest, absorb, transport, utilize, and excrete food.
• An essential nutrient cannot be synthesized (or synthesized fast enough) for metabolic needs.
• Nutrients are essential, when their removal from the diet causes a deficiency and decline in health which is corrected when added back into the diet.

Nutritional Deficiency

• Is when a person's nutrient intake is consistently below the recommended requirement.
• Anemia: Deficiency in iron, folate, and/or vitamin B12 hinders red blood cell transport of O2, impacting key development stages.
• Beriberi: Thiamine (B1) deficiency results in defective energy production and abnormalities in the nervous system.
• Scurvy: Vitamin C deficiency causes defective collagen production, leading to hemorrhaging and bleeding gums.
• Rickets: Vitamin D deficiency leads to defective bone growth.

Estimating Nutrient Requirement

• Nutritional requirements ensure optimal health
• Eating enough of a nutrient can prevent deficiency-related diseases, but does not guarantee optimal health.
• Early nutritional requirement recommendations did not consider differences in age, gender, body size, or physical activity.
• Nutritional requirements can be estimated statistically.
• The estimated average requirement (EAR) satisfies 50% of the population's needs.
• The recommended dietary allowance (RDA) satisfies 98% of the population's needs(EDA + 2 standard deviations)
• There is a tolerable upper limit when nutrient intake is excessive and causes health problems.
• Dietary reference intake (DRI) : Reference values for specific nutrients (EAR, RDA, and UL).

Starvation

• The Minnesota starvation experiment: Participants underwent 3 months on a high-calorie diet, followed by 6 months on a low-calorie diet, and 3 months of rehabilitation.
• Starvation led to weight loss, irritability, dizziness, tiredness, hair loss, reduced sex drive, and depression.
• The effects of starvation can take over a year to be reversed.

Nutritious Diet

• Adequate: Provides enough calories, essential nutrients, and fiber.
• Moderate: Avoids excessive calories or overconsumption of specific foods.
• Balanced: Prioritizes nutrient-dense foods over nutrient-poor options.
• Varied: Includes a diverse selection of foods.

Methods for Studying Nutrition

• Cell cultured models
• Animal models
• Epidemiological studies

Nutrient Classes

• Organic nutrients (contain carbon): Carbohydrates (including fiber), lipids, proteins, and vitamins.
• Inorganic nutrients: Minerals and water.
• Macronutrients (Carbohydrates, Lipids, and Proteins): Needed in large quantities.
• Micronutrients (Vitamins and Minerals): Needed in small quantities.
• Water is essential: It is neither a macro nor micronutrient.
• Water makes up ≈60% of the body
• Lipids make up ≈20-25% of the body
• Protein makes up ≈15% of the body
• Vitamins & Minerals combined make up ≈2% of the body
• Carbohydrates make up ≈0.5% of the body

Metabolism

• Metabolism is comprised of anabolism (building) and catabolism (breakdown).

Water

• Functions as a solvent in biochemical reactions and in catabolism (hydrolysis).
• Maintains vascular volume and aids in nutrient transport and temperature regulation.
• Adults need about 2.7L - 3.7L of water per day, roughly 20% of which comes from food. Average daily intakes:
• Carbohydrates: 250 - 350 grams
• Fat: 60 - 80 grams
• Protein: 50-80 grams

Water Toxicity

• Occurs when water intake exceeds the kidneys' processing ability (~0.9L per hour).
• Water is processed through the kidneys, where urine is made.
• Hyponatremia: Water/sodium imbalance that can occur from excessive fluid intake, under-replacement of sodium, or both.
• Hyponatremia causes CN edema and muscle weakness and can occur in elite athletes who consume large amounts of water without electrolytes.

Proximate Analysis

• It is the study of analytical methods for characterizing foods and their constituents.
• Knowing food composition ensures food safety and nutrition and informs consumer decisions.
• Government regulation maintains food quality, ensures food industry standards, promotes fair competition, and prevents economic fraud.
• Quality control ensures consistent food composition and characterizes raw materials.

Nutrient Density

• Caloric content does not reliably indicate the nutrient content of foods.
• Nutrient-dense foods have a high nutritional value relative to their caloric content.
• Empty calorie foods have high calories but low nutrients.

Steps of Proximate Analysis

1. Moisture (water content): Determines the water content by air-drying the feed sample.

• % moisture = (weight loss / wet weight sample) x 100%
• % dry matter = 100 - % moisture
• Determining water content is vital for cost evaluation, storage conditions, palatability, and nutrient concentration.
• Errors may occur from the removal of other volatile compounds, leading to slight dry weight underestimation.
• Human food labels are based on wet weight; animal feed emphasizes dry matter.

2. Ether extract (crude fat): Separates lipids via ether extraction by creating a solution (liquid) phase and a residue phase, the solution phase is then removed and dried out

• % crude fat = (weight of crude fat/wet weight of sample) x 100%
• Errors may occur from non-lipid substances in the extract (overestimation of crude fat).
• A new method uses gas chromatography on the ether extract to identify specific dietary fats.

3. Ash (mineral content): Inorganic residue remaining after burning off organic material is analyzed.

• It is important for nutritional labeling, quality/taste evaluation, microbiological stability assessment, nutritional requirement calculations, and manufacturing process optimization
• % ASH = (weight of ASH / wet weight of sample) x 100%
• Volatile minerals lost during burning can cause underestimation of mineral content.(now food labels must indicate Na content)

4. Nitrogen (crude protein): Determined via Kjeldahl analysis on dry matter assuming all nitrogen is protein and all protein contains has 16% nitrogen.

• 3 Steps:
• Digestion with sulfuric acids converts nitrogen to ammonia.
• Distillation separates ammonia.
• Titration quantifies the amount of ammonia.
• % crude protein = ( (Nitrogen in sample x 6.25)/ wet weight of sample) x 100%
• Errors may occur because protein does not always contain ≈16% nitrogen and other sources of nitrogen exist.

5. Crude fibre: Utilizes remaining residue from ether extract. Residue is boiled in acid, taken as remainder after this boiling is complete and boiled in alkali. The remainder is consists of ash and crude fibre, and once ignited.

Nitrogen Free Extract (NFE)

• Estimates digestible carbohydrates (CHO), starch and sugar content.
• % NFE = 100 – (% moisture + % crude fat + % ASH + % crude protein, + % crude fibre).
• NFE accumulates the errors from other components.
• The general notes of proximate analysis includes noting that it excludes information such as digestability and specific carbohydrate.

Dietary Fibre

• Dietary fibres are non-digestible complex carbs derived from the structural parts of plants.
• Insoluble fibres (cellulose, lignin, hemicellulose) remain intact and improve intestinal transit, bulking up feces.
• Soluble fibres (pectins, gums, mucilage) dissolve, form gels, slow gastric emptying, increase transit time, and decrease absorbtion speed
• Cellulose is a dietary and functional fiber and is poorly fermented by gut bacteria.
• Hemicellulose composition affects solubility and fermentability, and it is rich in brain legumes, nuts and peas.

Van Soest Method of Fibre Analysis in Feeds

• Use of detergent fibre analysis and separates insoluble fibres such as cellulose and hemicellulose as well as lignin.

Southgate Method of Fibre Analysis

• Provides info on sugars, starches, and fibres and is used for human nutrition food labels.

Digestive Systems

Gastrointestinal Tract (GI Tract):

• Composed of the: Mouth, Esophagus, Stomach . Small Intestine, Large Intestine, Caecum, Rectum
• Digestive system is the Gl tract along with related organs (salivary glands, liver, pancreas, gallbladder).

Terms for Dietary CHO and Digestion:

• Digestibility: Whether organisms have necessary enzymes
• Solubility: Whether a molecule can desolve in watery environments
• Fermentability: Whether the molecule can be broken down by the gut bacteria.

Digestion Systems

• Simple System w/o caecum- suited for nutrient dense low fibre food with non functional caecum and monogastric stomach

• Oral cavity- food is chewed with released enzymes: a-amylase and lingual lipase

• Stomach (cardia, fundus, body and antrum)- gastric emptying is triggered which releases: water, electrolytes, HCL and enzymes. Food turns into chyme.

• Small intestine- Site of nutrient digestion and absorbtion. Intestinal motility is controlled by circular and longitudinal muscles

• Large intestine ( colon)-Site of fermentation. Production of short chain fatty acids (SCFA) that doesn't provide much energy.

• The increasing surface area comesfrom: folds of the Kerckring, villi , and crypts

• 102-1012 bacteria per g content (region specific)

• 500-1000 species identified per person in the gut

• bacteria is important for fermentation of non-digestible CHO and produces lactate and SCFA

• Foods with probiotics attempts enrich the bacteria community

• Simple System w Functional Caecum occurs in Horse, rabbit, hamster and acts suited with large amounts of plant based food.

• Ruminant (Cattle sheep goats)- fermentation takes place bofore the intestine

• Rumen- large section of the stomach with rich bateria and rich blood supply. The lining of the rumen is made up of many small papillae.

• Reticulum- Captures small and trap nutrients

• Omasum- reabsorb water and filter materials

• Abomasum- Digestive enzymess

• Avian System- Birds: rapid digestion. Storage into for example the crop.

Digestion:

• Digestibility is a degree of the fraction to a nutrient
• Calculates nutrient ammount in feces
• Combining with food matrix Factors that affect:
• feed intake and particle size

Collection:

• Total colletion methids and indicator methods

Energy Terms

Cellular source: ATP, energy intake. 1 cal has many J 1:4. Energy in food equal energy we uses Energy in more than energy out: weight problems. Increase fat and lipids: insuline reistnace. Limited bone mess Negative in Calories vs kilo calories are differnt by factor of 1000 Bomb calorimetry.

Physiological Fuel Values

• Involves knowing heat of combustation as well as loss in urine and Apparent digestibility
• lipid ratio of H to O is greater than CHO that is why more kilo cal per fat vs carbs and protein
• Heat of combustion for fatty acids is affected by: Chain length and Degree of unsaturation:
• Heat increment of feeding (HIF) Thermic effect of food and involves 5-3-% expidenture by energy

Measuring Total Energy Expenditure

• Provides info abotu energy Expenditure

CHO Classification

• Complex vs Simple

Starch & Dextrin Formation

• 3 or more monosaccharides
• Oligosaccharides has 3-1- monomers.
• Glucose storage is glycogen
• Amylose: is a straight chain linear linked molecule
• Cellouse is a carbohydrate structure.

Other Carbohdrate facts:

• the body cannot down a carb
• Hemiketal vs hemlactel:

D. vs L

• position on O atom will determined

Fibre Discussion

• Maintains function and help but reduces
• Insoluble fibre decreases the contract

Lipid Discussion

• Transport mechanism is transport VLDL & LDL Overall transport Transport - - VLD & LDL Transports, and can delivere

• FA can be oxidized and then made by Acetyl Col,

• In blood stream and increase cardio vasscualr

Lipid Discussion

• transport is transport VLDL & LDL Overall Transport -- v d LDL Transport: and can deliverie in blood stream and increase cardio vassualc FA can be oxilized and oxidization by acetyl
• in blood stream and increase cardio vasusclaur