Victor TambunanErwin ChristiantoDepartment of NutritionFaculty of MedicineUniversitas Indonesia

Nutrition and GI System

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Nutrition and GI System

ReferencesBowman BA, Russell RM. Present Knowledge in Nutrition 9th ed., 2006

Mahan LK, Escott-Stump S. Food & Nutrition Therapy 12th ed., 2008

Wahlqvist ML. Food and Nutrition: Australasia, Asia and the Pacific, 1997

Gropper SS, et al. Advanced Nutrition and Human Metabolism 4th ed., 2005*

Found primarily in plant tissues

Small amount in animal tissues

Carbohydrate (CHO) in foods traditionally classified as:

Simple CHO (sugars): mono & disaccharides

Complex CHO: polysaccharides*

Classification Classification according to degree of polymerization (number of monomeric units)(Food and Agriculture Organization/World HealthOrganization Expert Consultation of Carbohydrates in Human Nutrition, 1998)*

The major dietary carbohydrates*Number of monomeric units*

Class (degree of polymerization*)SubgroupComponentsSugars (12)

Oligosaccharides (39)

Polysaccharides (>9)MonosaccharidesDisaccharidesPolyols (sugar alcohols)

MaltooligosaccharidesOther oligosaccharides

Starch

Non-starch polysaccharides (NSP)Glucose, galactose, fructoseSucrose, lactose, maltoseSorbitol, mannitol

MaltodextrinsRaffinose, stachyose, fructooligosaccharides (FOS)

Amylose, amylopectin, modified starchesCellulose, hemicellulose, pectins, hydrocolloids

1. Source of Energy1 gram CHO ~ 4 kcal

Glucose is the major source of energy for:- Nerve tissue- Red blood cellsUnder normal circumstances, glucose is the sole source of energy for the brainRoles of Carbohydrate2. Protein-Sparing ActionSufficient CHO to meet energy demands prevents the protein breakdown for this purpose*

Food Source of Carbohydrate*

CHOFood Sources- Starch & dextrins

- Glycogen Sucrose

Lactose Glucose FructoseGrains, vegetables (esp. tubers & legumes)Meat products, seafoodCane & beet sugars, molasses, maple syrupMilk & milk productsFruits, honeyFruits, honey, corn syrup

A great deal of the plant material that resists digestion inhuman diets originates from the cell walls of the tissuesof fruits, vegetables, & cereal grainsDefinitionPhysiological definition: the remnants of plant cells after hydrolysis by the enzymes of human digestives systemChemical definition: plant non-starch polysaccharides plus lignin*

Classification of FibreInsoluble fibre

Soluble fibre

Fibre-like substances

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Sources of Fibre ComponentsSolubleGumPectinb-glucanPsylliumOatLegumesGuarBarleyAppleCitrus fruitsStrawberryCarrotOatPlantago ovataInsolubleCelluloseHemicelluloseLigninWhite-wheat flourBranVegetablesBranWhole grainsMature vegetablesWheatFruits with edible seeds, such as strawberry*

Sources of (cont.)Fibre-like Substances Inulin

Fructooligosaccharides (FOS)

Chitosan*

Sources of (cont.)Inulin & FOS are prebioticsstimulate the growth and/or activity of good bacteria in the colon i. e. bifidobacteria (probiotic)Food Sources:

Chicory root Garlic Onion Banana Wheat Inulin & FOS ChitosanAnimal-derived materials that resist digestionFood source: Crustacea (shrimp, crab, lobster)*

Physical and Chemical Properties of Fibre & Fibre-like substancesWater insolubleNon-fermentable or partly fermentableNon-viscousHold waterWater solubleFermentable: fermentation yields short chain fatty acids (acetate, propionate, butyrate)Viscous/gelling

Insoluble fibreSoluble fibreWater solubleFermentableNon-viscousInulin & FOS*

Physiological Benefits of FibreReduce constipation, faecal mass, softness & frequency, and accelerate intestinal transitPromote growth of ileal & colonic mucosa (?)Enhance protection from bacterial infection (?)

Insoluble fibre*

Physiological Benefits (cont.)Delay gastric emptying and small intestine transitModulate GI motility Faecal mass, volume & softness (mild effects)Reduce diarrhoea ( water absorption)Promote growth of ileal & colonic mucosaProvides energy to the intestinal mucosa Colonic pH Protection from infection (barrier function, immunity) Glucose tolerance High total & LDL cholesterol levelsSoluble fibreincreases with viscosity*

Physiological Benefits (cont.)Promote healthy gut microflora (prebiotic/bifidogenic effect) Colonic pH (lactic acid production) Protection from infection (barrier function, immunity)Reduce diarrhoea and constipation (?) High blood glucose levels & improve blood lipids (?)Inulin & FOS*

Dietary soluble fibreGel formation in the stomach Delayed gastric emptyingUniform levels of CHO to the small intestine Insulin surgeFlattened blood glucose curvePossible mechanism by which soluble fibre lowers serum glucose*

Soluble Fibre Delayed gastric emptyingInterference withdigestive enzymesInhibition of cholesterol biosynthesis Flattened glucosecurveMay containlipase inhibitorsMay sequester lipid + CHO from digestive enzymes Bacterial fermentationproduces propionate Insulin secretionImpaired absorptionof lipid & CHOCholesterolcant be absorbedPropionate inhibitsHMG-CoA reductase Stimulation of HMG-CoA reductaseby insulinLOWER SERUM CHOLESTEROLPossible mechanisms by which dietary fibre lowers serum cholesterol Substrate forhepatic lipidsynthesis Exogenous cholesterol availablefor cholesterol synthesis Cholesterol biosynthesis

Dietary starch that resists digestive enzyme action and reaches the colon; a starch encased in a non- digestible plant seed coat or modified by cooking orprocessing can be resistant Western diets: resistant starch may be as much as 10% of daily starch intake (840 g/day)Starch-rich diets: resistant starch >>>

Recommended IntakesFAO/WHO expert consultation (1998): optimal diet should consist at least 55% of total energy from CHO obtained from a variety of food sources.

A wide range of intakes is regarded as acceptable---- up to 75% of total energyPedoman Umum Gizi Seimbang (PUGS) Indonesia: Sugar not more than 5% of total energy*

Recommended (cont.)Fibre: Adequate dietary fibre intake for adult (Institute of Medicine, Food, and Nutrition Board, 2002): 14 g per 1000 kcal

Ratio of insoluble to soluble fibre: 3 : 1can be obtained with 5 servings of fruits & vegetables and 6 servings daily of whole-grain breads, cereals, and legumes *

Triglycerides (triacylglycerols)

Cholesterol

PhospholipidsDietary Lipids*

Nutrition and GI System

TriglyceridesCombinations of fatty acids with glycerol Fats: solids

Oils: liquids*

Common Fatty Acids*

Trivial nameBiochemical abbreviationFood sourcesSATURATED Short-chain Butyric Caproic Caprylic Medium-chain Capric Lauric Myristic Long-chain Palmitic Stearic

C4:0 C6:0 C8:0

C10:0 C12:0 C14:0

C16:0 C18:0

Butter Butter Coconut oil

Palm oil Coconut oil Butterfat, coconut oil

Palm oil, animal fat Cocoa butter, animal fat

Common Fatty (cont.)*

Trivial nameBiochemical abbreviationFood sourcesMONO-UNSATURATED (MUFA) Oleic ErucicPOLY-UNSATURATED (PUFA) Linoleic a-linolenic Arachidonic Eicosapentaenoic (EPA) Docosahexaenoic (DHA)

C18:1 n-9 C22:1 n-9

C18:2 n-6 C18:3 n-3 C20:4 n-6 C20:5 n-3 C22:6 n-3

Olive, canola, peanut oilCanola oil

Seeds fats--corn, cottonseedSoybean oilLard, meatsSome fish oil, shellfishSome fish oil, shellfish

Classification and Food Sources of Omega Fatty Acids*

ClassFatty acidBiochemicalabbreviationFood SourcesOmega-3

Omega-6

Omega-9a-linolenic acidEPADHA

Linoleic acidArachidonic acid

Oleic acid C18:3 n-3 C20:5 n-3 C22:6 n-3

C18:2 n-6 C20:4 n-6

C18:1 n-9Soybean oilSome fish oil, shellfishSome fish oil, shellfish

Corn, cottonseed oilLard, meats

Olive, canola, peanut oil

Role of Fat In the Diet

In the Body*

Source of energy (9 kcal/g fat)Satiety value tends to leave the stomach relatively slowCarrier of fat-soluble vitamins (A, D, E, and K)Essential fatty acids supplyPalatability responsible for much of the texture & flavor of food

Constituent of cell membranesEnergy reserve as triglyceridesRegulator of body functions arachidonic acid (n-6 PUFA) a-linolenic acids (n-3 PUFA) precursors of eicosanoids (prostaglandin, thromboxane)4. Insulator prevent heat loss5. Protector protect vital organsRole of FatIn the BodyIn the Diet*

Essential Fatty AcidsEssential:

The body cannot synthesise or cannot make in sufficient amounts must obtain from the diet Absence leads to a defined deficiency stateNutritionally essential fatty acids:

linoleic acid & a-linolenic acidArachidonic acid is not an essential fatty acid can be synthesised from linoleic acid*

Prostaglandin & ProstacyclinThromboxaneLeukotriene Have many functions, including:

Regulation of blood pressure

Stimulation of pain & fever

Induction of blood clotting

Modify the processes of inflammation*

Omega-6 seriesOmega-3 seriesLinoleic acida-Linolenic acid18:2n-618:3n-3ElongationDesaturationArachidonic acidEicosapentaenoic acid20:4n-620:5n-3in platelets

Leukotriene4

Leukotriene5 Prostaglandin2

in blood vessels in leukocytesThromboxane2

Thromboxane3

Prostaglandin3

Production of eicosanoids from n-3 & n-6 fatty acids*

Cholesterol Is a fat-related compound belonging to sterols family

Not yield energy

Found only in animal foods

Component of cell membranes

Precursors of steroid hormones*

Cholesterol (cont.)Food high in cholesterol:

Brain

Egg yolks

Organ meats such as liver & kidney

LobsterFood Sources*

Food Sources (cont.)Lesser amounts occur in other animal food sources:

Meats, especially fatty meats

Whole milk

Cream, butter, cheese, ice cream, and other whole milk dairy products

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Recommended IntakesPedoman Umum Gizi Seimbang (PUGS) Indonesia:Lipids:

25% of total energy(at least 10% of total energy)*

There are only 20 common amino acids which make up most protein

Over 300 different amino acids occur in nature.Only L-a-amino acids occur in proteinsProteins are made up of chains of amino acids linked by bonds to form ribbon-like peptide chains.*

Nutritional Classification of Amino Acids:

Essential (indispensable)

Non-essential (dispensable)

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Essential (indispensable) amino acidsMust be supplied in the diet because:Cannot be synthesised in the bodyCannot be synthesised at a sufficient rate to meet body requirementsNon-essential (dispensable) amino acidscan be synthesised within the body*9 Essential amino acids:Phenylalanine, valine, threonine, methionine, tryptophan, histidine, isoleucine, leucine, & lysine

FunctionsMajor functions of proteins in the bodyPart of cell membranes

Enzymes & some hormones

Special proteins of blood: hemoglobin, albumin, transferrin4. Nucleoproteins: stabilise the structure of RNA & DNA

5. Antibodies

6. Contractile protein in muscle*

Complete proteins or proteins of high biological value contain all of the essential amino acids in proportions capable of promoting growth when they are the sole protein in the diet

All animal proteins, except gelatin, are complete proteins*

Incomplete proteins or proteins of low biological value lack or have limited amounts of one or more of the essential amino acids and so are incapable of promoting growth when they are the sole protein in the diet*

Food SourceMost of the foods we eat contribute some protein to the diet Protein is the major component of lean meat, fish, and egg white (protein contributes >20% of energy) Cereals contribute intermediate amounts of protein (7% to 18%) Fruits & vegetables contribute much less (0% to 5%)*

Protein in foods*

Protein amount in food Food (g/100 g) High content (protein contributes >20% of energy) Beef and lamb (lean meat, cooked) 28 Chicken 25 Fish (whiting, without batter) 18 Eggs 12 Milk 3.3 Peas (fresh or frozen) 5 Medium content (protein contributes 7 to 8% of energy) Bread (white) 7.8 Corn (sweet) 4.1 Potatoes (cooked) 1.6 Rice (cooked) 2.2 Low content (protein contributes 0 to 5% of energy) Cassava 0.7 Apples 0.3 Butter and margarines

Dietary Reference Intakes (DRIs) for ProteinRDA: Recommended Dietary AllowancesAI : Adequate IntakeWashington DC, 2002. The National Academies Press*

Life-Stage GroupRDA/AI (g/kg/day)Infants13 years413 years1418 yearsAdultsPregnant (using pre-pregnancy weight) women

Lactating women1.5 1.10.950.850.81.1

1.1

Excess dietary proteinMay adversely affect calcium (Ca) statusCa absorption is enhanced by higher intakes of protein, but urinary excretion of Ca is also Rate of Ca urinary loss is higher than Ca uptakeThere may be a net loss of Ca*

World Health Organisation (WHO), 2003Contribution of Macronutrients to Total Energy:

Carbohydrates5575% Lipids1530% Protein1015%*

081310733442dr.erwin.christianto@gmail.com

Nutrition and GI System

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