Nutrition DepartmentMedical School

University of Sumatera Utara

الرحيم الرحمن الله الرحيم بسم الرحمن الله بسم

FOOD GLYCEMIC INDEX

Ratio of the blood glucose respond to a given food compared to a standard (typically glucose or white bread)

Influenced by starch structure, fiber content, food processing, physical structure, food temperature and other macronutrients in the meal, such as fat

The number is based on a serving of food that would provide 50 grams of carbohydrate

Glycemic index (G.I.) Reflects the degree to

which ingestion of the food raises blood glucose and insulin levels.

Area under the glucose G.I. = curve for 50g food x

100% Area under the curve for 50g glucose (white bread)

Glycemic index of selected foods

Beansbaby lima 32baked 43black 30brown 38butter 31chickpeas 33kidney 27navy 38pinto 42red lentils 27split peas 32soy 18Breadsbagel 72Kaiser roll 73pita 57pumpernickel 49rye 64rye, whole 50white 72whole wheat 72waffles 76CerealsAll Bran 44Bran Chex 58Cheerios 74Corn Bran 75Corn Chex 83Cornflakes 83Cream of Wheat 66Crispix 87Grapenuts 67Grapenuts Flakes 80Life 66Muesli 60NutriGrain 66Oatmeal 53Oatmeal 1 min 66Puffed Wheat 74Puffed Rice 90Rice Bran 19Rice Chex 89Rice Krispies 82Shredded Wheat 69Special K 54

Biscuitsoatmeal 55shortbread 64Vanilla Wafers 77CrackersKavli Norwegian 71rye 63saltine 72DessertsAngel Food Cake 67bran muffin 60Danish 59fruit bread 47pound cake 54sponge cake 46Fruitapple 38apricot, canned 64apricot, dried 30banana 62banana, unripe 30cherries 22fruit cocktail 55grapefruit 25grapes 43kiwi 52mango 55orange 43pear 36pineapple 66plum 24raisins 64strawberries 32watermelon 72

Grainsbarley 22brown rice 59buckwheat 54bulger 47chickpeas 36cornmeal 68hominy 40millet 75rice, instant 91rice, parboiled 47rye 34sweet corn 55wheat, whole 41white rice 88wh. rice, high amylose 59Juicesapple 41grapefruit 48orange 55pineapple 46Milk Productschocolate milk 34ice cream 50milk 34yogurt 38Pastabrown rice pasta 92linguine, durum 50macaroni 46macaroni & cheese 64spaghetti 40spag. prot. enrich. 28vermicelli 35vermicelli, rice

The term dietary fiber refers to nondigestible (by human digestive enzymes) CH and lignin that are intact and intrinsic in plants

Functional fiber consist of nondigestible CH that have been isolated, extracted or manufactured and have been shown to have beneficial physiologic effects in humans

Total fiber is the combination of dietary fiber and functional fiber in the food product

Dietary fibers Functional fibers

Cellulose CelluloseHemicellulose PectinPectin LigninLignin GumsGums -glucans-glucans Fructans Fructans Chitin & chitosanResistant starch Polydextrose &

polyols Psyllium Resistant dextrins Resistant starches

In terms of their chemical composition

Fibers are composed primarily of the non-starch polysaccharides cellulose, hemicelluloses, pectins, gums, and mucilages

The only noncarbohydrate components of dietary fibers are lignins, which include complex alcohol derivatives

Classification of FibersType Noncomponent(s) Physiological

EffectsMajor Food

SourcesInsoluble (Nonfermentable) : undigestible dietary fibers generally DO NOT dissolved in hot water and are not generally metabolized by bacteria in the large intestineNoncarbohydrate Lignins Increase fecal bulk Whole grainsCarbohydrate Cellulose

HemicellulosesIncrease fecal bulkDecrease intestinal transit time

All plantsWheat, rye, rice, vegetables

Soluble (Viscous) : dietary fiber either dissolve in hot water, and bacteria in the large intestine can break down soluble fibersCarbohydrate Pectins,gums,

glucans, mucilages, some hemicelluloses

Delays gastric emptying, slows

glucose absorption, can

lower blood cholesterol

Fruits, citrus, vegetables, oat products, rice, soybean fibers

beans, thickeners added to food and

psyllium seeds

Selected properties and physiological & metabolic effects of fiber

Solubility in water Soluble fiber - delay gastric emptying - increase transit time (through slower movement - decrease nutrient absorption (glucose) Insoluble fiber - decrease intestinal trasit time - increase fecal bulk

Water holding/hydration capacity and viscosity

- delayed emptying of food from stomach - reduced mixing of gastrointestinal contents with digestive enzyme Adsorption or binding ability - diminished absorption of lipids - increase fecal bile acid excretion - lowered serum cholesterol concentration

Degradability / fermentability - fermentable fibers SCFA - water & sodium absorption in the

colon - mucosal cell proliferation - provision of energy - acidification of luminal environment - nonfermentable fibers - detoxification - fecal bulk

Adequate intake ♂ 19 – 50 yrs 38 g ≥ 51 yrs 31 g ♀ 19 – 50 yrs 25 g ≥ 51 yrs 21 g To obtain fiber via the diet, food sources

of fiber need to be varied and complimentary

Artificial sweeteners - energy (-) - nonnutritive sweeteners - saccharin, aspartame, acesulfam

potassium, sucralose, neotame

Sugar replacers - energy (+) - nutritive sweeteners - sugar alcohol (mannitol, sorbitol, xylitol)

Saccharin

SN

O

OO

H

Saccharin

Rapidly excreted in the urine Does not accumulate in the body Relative sweetness 450 Acceptable daily intake 5 mg/kgBW Average amount to replace 1tsp sugar

12 mg In 2000 was removed from the list of

suspected cancer-causing substance

Aspartame

N

OO

O

N

O

OCH3

H2

H

H

Aspartame

Aspartic acidPhenylalanine

Methanol

Long term consumption is not associated with any adverse health effects

Contain phenylalanine & aspartic acid Warning to people with PKU

Relative sweetness 200 Energy 4 kkal/g Acceptable daily intake 50 mg/kgBW Average amount to replace 1tsp sugar

18 mg

Acesulfame

OS

N

O

O

OH

H

H

H

Acesulfame

Relative sweetness 200 Energy (-) Acceptable daily intake 15 mg/kgBW Average amount to replace 1tsp sugar

25 mg

Sucralose Relative sweetness 600 Energy (-) Acceptable daily intake 5 mg/kgBW Average amount to replace 1tsp sugar

6 mg Passes through the GI tract undigested

& unabsorbed

Neotame The most recent Relative sweetness 8000 very little

is needed Energy (-) Acceptable daily intake 18 mg/kgBW Average amount to replace 1tsp sugar

0.5 μg

Sugar replacers

Sugar alcohols Relative sweetness energy (kkal/g)

Isomalt 0.5 2Lactitol 0.4 2Maltitol 0.9 2.1Mannitol 0.7 1.6 Sorbitol 0.5 2.6Xylitol 1.0 2.4

In food phytochemicals impart tastes, aromas, colors & other characteristics

Give hot peppers their burning sensation, garlic its pungent flavor, etc

In the body acting as antioxidants, mimicking hormone, and supprssing the developmentof disease

E.g. :Carotenoids, flavonoids, phytoestrogens, capsaicin, etc

flavonoids Include flavones, flavonols, isoflavones,

catechin, etc Possible effect : - act as antioxidants - scavenge carcinogens - bind to nitrate in the stomach,

preventing conversion to nitrosamine Food source : black tea, green tea,

onions, soybeans & soy products

Phytosterols Plant derived compounds that have

structural and functional similarities to human estrogen

Include genisten, daidzein and glycitein

Food sources : soybeans, soy flour, tofu, soy milk, textured vegetable protein and other legume product

Possible effects

Estrogen inhibition may produce this action : Inhibit cell replication in GI tract Reduce risk of breast, colon, ovarian,

prostate and other estrogen-sensitive cancers

Reduce cancer cell survival

Estrogen mimicking may reduce risk of osteoporosis

Saturated Fatty Acids (SFA) 1% reduction SFA = 2% reduction of

cholesterol SFAs 12:0 – 16:0 hypercholesterolemic Most potent 14:0 (myristic acid)

Kris-Etherton PM & Yu S, ‘Individual fatty acids effects on plasma lipids and lipoproteins: human studies’, Am J Clin Nutr 1997;65 (suppl):1628S–44S

Monounsaturated (MUFA)

Oleic acids (18:1) : hypocholesterolemic , lowers LDL-C

Effects are less than linoleic acids HDL raises

Polyunsaturates (PUFA)

18:2n-6 (linolenic acid) decreases TC & LDL-C

HDL effect: not significant

Trans Fatty Acids Formed in the hydrogenation process Mostly elaidic acid(trans 18:1n-9) Elevates LDL-C and reduces HDL-C

Cholesterol Less potent regulator of plasma

lipoprotein than fatty acids Wider variation in response to dietary

cholesterol Synergy of cholesterol and fatty acids ?

Schaefer EJ, ‘lipoproteins, nutrition, and heart disease’, am J Clin nutr2002;75:191-212

Paracelsus (1493-1541) All substances are poisons, there is

none which is not a poison. The right dose differentiates a poison and a remedy.