Chapter10

Nutrition and food hygiene Dr. Quanjun Lu Department of nutrition and Food hygiene TEL:67781923 Email:[email protected] 2006.11.15

Nutrition and food hygiene 1.Nutrition 2.Food Hygiene

Introduction 1.Concept of nutrition 2.Content of nutrition 3.Classification of nutrients 4.Research methods

What is nutrition • The word 'Nutrition" comes from a Latin word which means to 'nourish" or to "to feed". • Nutrition covers many areas including:  the science of food  why people choose certain foods  what foods are made of  the nutrients in foods  how the body uses food  food digestion  food functions

Nutrition is • “the science of food, the nutrients and the substances therein, their action, interaction, and balance in relation to health and disease, and the process by which the organism ingests, absorbs, transport, utilizes, and excretes food substances”----The Council on Food and Nutrition of the American Medical Association

Physiology of Nutrition • Nutrition is the process by which the body metabolizes and utilizes the nutrients from food. • Nutrients are digested, absorbed by the blood or lymphatic system, and transported to the body’s cells.

Physiology of Nutrition • Digestion is the process by which ingested foods are broken down in the GI tract to smaller segments in preparation for absorption.

Physiology of Nutrition • Absorption is the process by which the end products of digestion pass through the epithelial membranes in the small and large intestines into the blood or lymph systems.

Physiology of Nutrition • The end products of digestion are monosaccharides (simple sugars), amino acids, glycerol, fatty acid chains, vitamins, minerals, and water.

Physiology of Nutrition • Metabolism is the aggregate of all chemical reactions and process in every body cell, such as growth, generation of energy, elimination of wastes, and other bodily functions as they relate to the distribution of nutrients in the blood after digestion.

Physiology of Nutrition • Metabolic rate refers to the rate of heat liberation during chemical reactions.

Metabolism • Energy – A calorie is the unit of measurement used to express the quantity of energy released during metabolism. – Energy is expressed in terms of kilocalories. – Basal metabolic rate (BMR) represents the energy needed to maintain essential physiological functions.

Metabolism • Excretion – Digestive and metabolic waste products are excreted through the intestines and rectum. – Other excretory organs are the kidneys, sweat glands, skin, and lungs.

Nutrients Come from Food • • • •

Provide energy to fuel our bodies Provide building blocks for new tissue Vital for growth and maintenance Some are essential i. e. we can’t make them (or enough) and so must get them from our diets

Nutrition and Health • Poor diet and sedentary lifestyle increase the risk for chronic diseases – – – –

Disease of the heart (31% of all deaths) Cancer (23%) Cerebrovascular disease (~7%) Diabetes (3%)

The Six Classes of Nutrients • • • • • •

Carbohydrates Fats Proteins Vitamins Minerals Water Essential nutrients Nonessential nutrients

Nutrients Come from Food

FOOD

DIGESTION / ABSORPTION

NUTRIENTS

PROCESSING / METABOLISM

(converts the basic nutrients into many other needed chemicals / biochemicals)

DIGESTION, ABSORPTION Large molecules: Polysaccharides, proteins, triglycerides Enzymes (digestion)

Small molecules: Monosaccharides, amino acids, fatty acids Absorption Small molecules in the blood, to liver, muscles, neurons etc.

ESSENTIAL NUTRIENTS

Energy Yielding Nutrients • • • • • •

Carbohydrates: 4 kcal/gm Protein: 4 kcal/gm Fat: 9 kcal/gm (Alcohol: 7 kcal/gm) Adjusted for digestibility Account for substances (in food) not available for energy use

Carbohydrates • • • • •

Composed of C, H, O Provide a major source of fuel for the body Basic unit is monosaccharide (glucose) Simple and Complex CHO Energy yielding (4 kcal /gm)

Nutrients • Nutrients are essential dietary factors, such as vitamins, minerals, essential amino acids, and essential fatty acids, that cannot be synthesized by the body at a sufficient rate. • Sources of energy are not classed as nutrients and neither is water nor dietary fibre.

Classification of nutrients • Energy • Macro-nutrients: Protein,Fat,Carbohydrates • Micro-nutrients: Inorganic salt(minerals) and Vitamins • Other compositions: Water,Fibre, Phytochemicals

Nutrients • • • • • •

Water Vitamins Minerals Carbohydrates Proteins Lipids

Nutrients • Water – Accounts for 60% to 70% of an adult’s total body weight and 77% of an infant’s weight. – Water and electrolytes are substances that must be acquired from the diet. – Body water requirements are met through consumption of liquids and foods and the oxidation of food.

Water • Vital to life • Requirement about 8 cups/day*** • Is a solvent, lubricant, medium for transport, chemical processes, and temperature regulator • Makes up majority of our body (60%) *** not necessarily as glasses of water – can be any food/drink containing water (varies with size, activity, temperature)

Nutrients • Vitamins – Organic compounds that aid in the regulation of cellular metabolism and assist in the biochemical processes that release energy from digest food – Vitamins are classified as fat-soluble or watersoluble.

Vitamins • Fat-soluble vitamins:A,D,E,K • Water-soluble vitamins:Thiamin,Riboflavin,Niacin,Folic Acid etc.

Vitamins • • • • • •

Composed of various elements Essential for life Enable chemical reactions Needed in tiny amounts Fat soluble or Water soluble Yield no energy

Nutrients • Minerals – Serve as catalysts in biochemical reactions. – Classified according to daily requirement: • Macrominerals (quantities of 100mg or greater) • Microminerals (trace elements, quantities less than 100 mg)

Minerals • Inorganic substances • Function in cellular process, nervous system, water balance, bones • Needed in tiny amounts • Not destroyed in cooking • Trace minerals/Major minerals • Yield no energy

Inorganic salt • Macro-elements: content >0.01%Body weight e.g. Calcium,Phosphorus, Sulfur,Potassium, Magnesium, Chloride, Sodium • Micro-elements(trace elements): content<0.01%Body weight e.g Iron,Zinc, copper,Selenium,Fluoride, Chromium,Manganese, Iodine,Arsenic, Boron, Molybdenum, Nickel, Silicon,Vanadium,

Nutrients • Carbohydrates – Organic compounds composed of carbon, hydrogen, and oxygen – Primary source of energy for the brain and the preferred fuel for the body

Nutrients • Carbohydrates – Monosaccharides (simple sugars) include glucose, galactose, and fructose. – Disaccharides (double sugars) include sucrose, lactose, and maltose. – Polysaccharides (complex sugars) include glycogen, cellulose (fiber), and starch.

Nutrients • Proteins – Organic compounds that contain carbon, hydrogen, oxygen, and nitrogen atoms – Essential for almost every bodily function

Proteins source of amino acids for growth & new proteins (for tissues, antibodies, enzymes, hormones etc.), can provide energy, are important structural and functional components of bodies

• Composed of C, O, H, N • Basic unit is amino acid (string of beads) • Make up bones, muscles, other tissues, and components • (9) Essential amino acid • (11) Nonessential amino acid • Energy yielding (4 kcal /gm)

O ll -HN-CH-C-O| R (20 different side chains)

Space-filling model of the protein hemoglobin

Fig. 1.1c

Nutrients • The end products of protein digestion are amino acids. • Nonessential amino acids can be synthesized in the cells. • Essential amino acids must be ingested in the diet because they cannot be synthesized in the body.

Nutrients • Proteins are also classified as complete or incomplete. – High-biological-value proteins (complete proteins) contain all the essential amino acids. – Low-biological-value proteins (incomplete proteins) lack one or more essential amino acid.

Nutrients • Protein Deamination is the process of removal of (degradation) amino groups from the amino acids.

Nutrients • Other physiological processes occur during protein deamination. – Gluconeogenesis – Ketogenesis – Nitrogen balance – Positive nitrogen balance – Negative nitrogen balance – Obligatory loss of proteins

Nutrients • Lipids (fats) – Organic compounds are the only essential nutrients that cannot mix with water and therefore, must be emulsified by molecules to be absorbed.

Lipids The other major energy source (higher energy content/weight than carbohydrate). Supplies essential fatty acids, necessary for adsorption of fat soluble vitamins, vital components of membranes. • • • • • • • • •

Composed of C, H and fewer O Basic unit is fatty acid Triglyceride is the major form of lipid Fats and oils Unsaturated Fatty Acids Saturated Fatty Acids Trans fatty acids Essential Fatty Acids Energy yielding (9 kcal /gm)

Nutrients • Fatty Acids – Simplest form of lipids and the basic components of more complex lipids – Saturated fatty acids form fats, which are glycerol esters of organic acids whose carbon atoms are joined by single bonds. – Unsaturated fatty acids form glycerol esters of organic acids whose carbon atoms are joined by double or triple bonds.

• Monounsaturated Fatty Acids • Polyunsaturated Fatty Acids

Nutrients • Fatty Acids – Monounsaturated fatty acids are formed esters with one double or triple bond. – Polyunsaturated fatty acids form esters that have many carbons unbonded to hydrogen atoms. – Hydrogenated or trans-fatty acids are another category of fat that is not naturally occurring but man made.

Nutrients • Most Important Lipids – Triglycerides are composed of three fatty acid cells attached to a glycerol molecule. – Phospholipids are composed of one or more fatty acid molecules and one phosphoric acid radical; they usually contain a nitrogenous base. – Cholesterol is produced by the body and is considered a fat; it is also found in whole milk and egg yolk.

Promoting Proper Nutrition • Recommended Daily Allowances (RDAs) • The Food Guide Pyramid outlines six groups of food and the number of servings based on dietary guidelines and the basic four food groups.

Promoting Proper Nutrition • Societal Concerns – One-third of the U.S. population is considered overweight. – Obesity is becoming an epidemic. – Undernutrition is a specific problem for the elderly and for people with eating disorders.

Weight Management • Overweight is an energy imbalance in which more food is consumed than needed. • An underweight person expends more calories than are consumed.

Weight Management • Anorexia nervosa (self-starvation) disrupts metabolism because of inadequate calorie intake. • Bulimia nervosa refers to food-gorging binges followed by purging of food, usually through selfinduced vomiting or laxative abuse.

Factors Affecting Nutrition • • • • •

Age Lifestyle Ethnicity, Culture, and Religious Practices Economics Gender

Contents • • • • •

Basic nutrition Community Nutrition Nutrition and Diseases Food Hygiene Food Poisoning

Methods of estimating an individual’s dietary intake • Dietary recall • Food diary • Complete chemical analysis

References • • • • • •

American J.of Nutrition British J.of Nutrition Food Science Food Chemical Toxicology Nutrition Abstract & Review J.of Nutrition

Chapter 1 Energy requirements • Under-nutrition(malnutrition) remains a leading cause of mortality and morbidity in developing countries worldwide. In industrialized countries, the major nutritional problem is one of surfeit, with excess dietary energy and fat contributing to the disproportionate increase in metabolic disease prevalent in our society.

Dietary Reference Intakes (DRIs) • DRIs are reference values that are quantitative estimates of nutrients intakes to be used for planning and assessing diets for healthy people. They include RDAs as goals for intake by individuals, but also present three new types of reference values. These include the Adequate Intake(AI ),the Estimated Average Requirements(EAR), and the Tolerable Upper Intake Level(UL)

Recommended Dietary Allowance(RDA) • RDA is the dietary intake level that is sufficient to meet the nutrient requirement of nearly all(97 to 98 percent) healthy individuals in particular life stage(life stage considers age and when applicable, pregnancy or lactation) and gender group.

Estimated Average Requirements( EAR) • EAR is the amount of nutrient that that is estimated to meet the nutrient requirement of half the healthy individuals in a life stage and gender group. A requirement is defined as the lowest continuing intake level of a nutrient that will maintain a defined level of nutrient in an individual.

The Adequate Intake(AI) • AI is provided instead of a RDA when sufficient scientific evidence is not available to calculate an EAR. The AI is based on observed or experimentally determined estimates of nutrient intake by a group(or groups) of healthy people. • The primary use of the AI is as a goal for the nutrient intake of individuals.

Tolerable Upper Intake level (UL) • UL is the 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.As intake increase above the UL,the risk of adverse effects may increase.

• ULs are useful because of the increased availability of fortified foods and the increased use of dietary supplements in the world. ULs may be based on total intake of a nutrient from food, water, and supplements if adverse effects have been associated with total intake. However, if adverse effects have only been associated with intake from supplements or food fortificants, the UL is based on nutrient intake from those sources only, not on total intake. This is specified for each nutrient for which a UL is given.

If the standard deviation(SD)of the EAR is available and the requirement for the nutrient is symmetrically distributed, the RDA is set at 2 SDs above the EAR; RDA =EAR + 2 SDs • If data about variability in requirements are insufficient to calculate a SD, a coefficient of variation for the EAR of 10 percent is ordinarily assumed (the coefficient of variation [CV]is equal to the SD÷ EAR.The resulting equation for the RDA is then RDA=1.2× EAR. If the estimated coefficient of variation is 15 percent as it is for niacin, the formula would be RDA=1.3 × EAR.

• The RDA for a nutrient is a value to be used only as a goal for dietary intake by healthy individuals. • The RDA is not intended to be used to assess the diets of either individuals or groups or to plan diets for groups.

Energy sources • Dietary macronutrients-carbohydrates, fat, protein and alcohol all provide energy. • Energy values are about 4kcal/g(16kJ/g) for carbohydrates(starch protein,9kcal/g(37kJ/g)

and for

7kcal/g(29kJ/g) for alcohol.

sugar)and fat,

and

Basics • ATP (Adenosine Triphosphate) – Storage molecule of chemical energy used in most metabolic processes – ATP ↔ ADP + Pi + Energy

• Kilocalorie (Kcal or C) – Energy value of food – 1kcal = energy required to raise 1kg of water 1oC

Functions • Energy is required by all living organism to support life.Plants use the energy of sunlight to create complex carbohydrate, fat and protein. All animals including humans , then consume and digest the constituents to extract energy.

Food energy • The total energy content of food is the amount of energy released when food is completely burnt in air to CO2 and H2O,that is the heat of combustion. • The total energy is equal to the sum of the digestible and the non-digestible energy.

Total energy • Digestible energy is the amount of energy that can be absorbed from food and usually accounts for about 95% of the average Western diet. • Non-digestible energy is the energy in food, for example in cellulose, that we cannot break down and is last in faeces.

Human energy requirement • Human energy requirement is defined as the energy intake that will balance energy expenditure when the individual has a body size, composition and level of physical activity consistent with long-term good health. Energy requirements therefore vary according to body size, body mass,nature of diets, age, sex, state of health, and climate, as well as genetic differences.

Metabolizable energy • Metabolizable energy is the energy available to the body for use ;it has three fates: • 50% is lost as heat; • 5-10%of energy is used up in digestion, absorption,and transport of food.This is as ether thermic effect of food,diet-induced thermogenesis, or post-prandial thermogenesis (they all mean the same thing) • Only about 25-40%of energy is trapped as ATP,that is ,the body is only 25-40% efficient.

Energy expenditure • Energy expenditure includes several components; Basal metabolism, the thermic effect of exercise(TEE), the thermic effect of food (TEF,formerly known as specific dynamic action, and facultative thermogenesis (also known as adaptive thermogenesis)

Basal metabolic rate(BMR) • The BMR is the energy used to carry out normal body functions such as blood flow, breathing,and so on,that is ,it is the energy expended doing nothing! • At rest,lying down but not asleep; • At a constant,warm temperature. • Assessed about 12h after the last meal or any exercise.

Resting Metabolic Rate: • RMR is usually the greatest contributor (60%~70%) to total energy expenditure. RMR is a measurement of the energy expended for maintenance of normal body function and homeostasis plus a component for activation of the sympathetic nervous system.

RMR • RMR is measured with the subjects in a supine and sitting position in a comfortable environment several hours after a meal or significant physical activity. The basal metabolic rate, originally defines by Boothby and Sandiford,is measured in the morning upon awakening, before any physical activity, and 12-18 hours after a meal.It may be slightly lower than RMR,but the difference is small and RMR is now the more commonly used measurement.

The calculating formula of RMR suggested by WHO(1985) Age(years) Formula(male) Formula(female) 0~ (60.9×W)-54 (61.0×W)-51 3~ (22.7×W)+495 (22.5×W)+499 10~ (17.5×W)+651 (12.2×W)+746 18~ (15.3×W)+679 (14.7×W)+496 30~ (11.6×W)+879 (8.7×W)+829 >60 (13.5×W)+487 (10.5×W)+596

Body composition • An average 72kg man is composed of 15%fat 85%fat-free mass • Fat-free mass or lean body mass(LBM) is made up of 72% water 20% protein 8% bone mineral

Thermic effect of exercise(TEE) • (TEE) is second largest component of energy expenditure. It represents the cost of physical activity above basal levels. In a moderately active individual it comprises 15%~30% of total energy requirements. Of all the components of energy expenditure,TEE is most variable and therefore most amenable to alteration.

Physical activity ratio • The PAL can be measured for where activity is expressed as a multiple of the BMR(i.e BMR=1) • PAL =metabolic rate during exercise÷ BMR • Activity lying sitting standing football • PAL 1.0 1.2 1.7 7.0

Thermic effect of food(TEF) • (TEF) refers to the increase in energy expenditure above RMR that occurs for several hours after the ingestion of a meal. TEF is the results of energy expenditure to digest ,transport, metabolize, and store food.On average TEF accounts for about 10% of daily energy expenditure and varies depending on the metabolic fate of ingested substrate.

Facultative thermogenesis • Facultative thermogenesis is readily demonstrable in animals but is less well described in humans.It appears to account for less than 10%-15% of total daily energy expenditure but may have significant effects on long-term weight changes. Facultative thermogenesis is the change in energy expenditure induced by changes in ambient temperature,food intake, emotional stress,and other factors.

• The energy requirements of individuals in good health can vary from about1 450 kcal/day (6MJ/day) for small sedentary women, to 4 250 kcal/day(18MJ/day) for large very active men. • The requirements of population groups vary from 1 900kcal/day (8MJ/day) in some African countries to 2 150 kcal/day(9MJ/day) in some Asia countries, to 2 300-2 350kcal/day(9.69.8MJ/day) in Europe and North America. These variations are largely a reflection of average body size.

• Expressed as kilocalories per kilogram of body weight, the requirements of more active populations in the developing world are greater than those of typically sedentary people in the developed world.Figures are approximately 38kcal/kg(160kJ/kg) in Africa, 40kcal/kg(170kJ/kg) in Asia,and 33kcal/kg(140kJ/kg) in Europe and North America. • Absolute and relative energy requirements in the developed world have decreased remarkably in the second half of the twentieth century,reflecting the increased use of machines to replace human physical effort at work,at home and for transport.

• Human energy metabolism includes energy intake and energy output.Energy balance (intake minus output)can be in a state of equilibrium,negative(where energy intake is less than energy output) or positive (where energy intake is more than energy output).Positive energy balance,leading to weight gain as excess energy intake is converted to adipose and lean tissue,may be caused by high energy intake,by low levels of energy output,or by a combination of the two.

Influence factors • Nutritional status • thyroid function • sympathetic nervous system activity

Other factors • • • •

Environmental temperature changes Pregnancy and lactation Growth Age

Energy deficiency • Chronic energy deficiency leads to negative energy balance and weight loss as body tissues are broken down(catabolised) to meet the body’s requirement for energy.Public health problems associated with energy intake and output have been identified as problems of deficiency in the developing world and problems of excess in the developed world.

OBESITY • Obesity results from an imbalance between the input,storage and expenditure of energy ;that is energy intake is greater than energy expenditure. • Obesity can be defined or graded in term of the body mass index(BMI) • BMI(kg/m 2)=weight÷ (height)2

The grading of BMI • • • •

20-25 ideal weight 25-35 obesity grade I(over weight) 30-35 obesity grade II (obese) 35+ obesity grade III

Obesity

Definition: Medical term for overfatness frequently resulting in a significant impairment of health. Difference of overweight and obesity Overweight—excess weight for height by standards, such as actuarial tables. Ob—refer to excess body fat. *some football player: overwt due to lean body mass, but not Ob. *some inactive individuals w/little muscle may be obese but not overweight. The normal proportion of BWt as fat is: 15-20%----------M 20-25%----------F

NIH (National Institute of Health) BWt. of 20% over desirable weight has adverse effects on health. Pattern of fat distribution throughout the body is more impt. factors than total adipose tissue mass. Fat in abdominal region is greater risk of some chronic disease than others.

Classification of Ob: 1.base on the number and size of adipose cells: hypertrophic Ob.: normal number of adipocytes but large quantities of fat in each cell. Often w/mild,moderate ob, beginning in middle age. Hyperplastic Ob: too many adipocytes, each containing fat reasonably normal in quantity. Marked ob dating to early childhood.

Normal adipocytes

After Wt. loss

Hypertrophic Ob.

Hyperplastic Ob

2. the regional fat distribution a) android (male): apple shaped, upper body Ob b) gynoid (famale): pear shaped, lower body Ob To determine the two types of Ob: Waist/hips ratio Normal-----0.7 Lower body ob---<0.7 Upper body Ob--->0.7 fat below the waist is more difficult to lose wt. even under strict dieting.

Causes of Ob. :

1.calories: 2.genetics: two ob parents—73% chance of having ob offspring one ob parent—41.2% chance of having ob offspring two lean parents—9% chance of having ob offspring

3.brown fat: in adult, only located around neck and chest, rich mitochondria, can burning up calories. Ob—fewer brown fat cells or dysfunction 4.LPL: 5.ATPase: help to burn off 15-40% off all calories not used during physical activity. Ob has 20-25% less ATPase vs. a person of normal wt. 6.leptin: hormone secreted by fat cells only, response to an increase in fat mass and acts on the hypothalamus of the brain to through the control of appetite and energy expenditure.

Feeding 

leptin secretion ⊕ starvation  ⊕ Hypothalamus ⊕  Neuropeptide Y synthesis, secretion ⊕  appetite

Assessment of Ob: 1.BWt: ideal BWt. （ kg ） = height （ cm ） 105 >10% ideal BWt—overweight >20%----------------Ob 2.BMI: BWt. (kg)/height (m)2 20-24.9----normal 25-29.9----low risk 30-40------moderate risk >40--------Ob. High risk 3.Skinfold thickness: triceps skinfold for age 25-45: M—18mm F—23mm

Medical complications: Diabetes, hypercholesterolemia, high plasma TG, hypertension, heart disease, cancer, gallstone, arthritis. *DM: 2.9 x in Ob than normal wt , fasting blood glucose increase 2 mg/dl for each kg of excess BWt.

Wt. reduction: diet, exercise, behavioral modification, appetite suppressants, surgical treatment. Major components of caloric expenditure:

1) basal metabolic rate: 2) dietary thermogenesis 3) physical activity

60-70% 5-10% 25-35%

Caloric requirement: F-------12-14× ideal BW(lb) M------14-16× ideal BW(lb) To lose 1 lb/w, must take in 3500 calories fewer than he/she expends. e.g. to lose 1 lb/w, has to maintain a  energy balance of 500 calories/day dieting, or increase activity (running 45’, tennis 60’,walking75’, bike 90’, golf 120’). In normal diet: CHO:50-55en% (min.100g/d); Pr: 10-15en% (min. 0.8mg/kg.d); Fat: 30-35en%

Chapter 2 Protein and Amino Acid • Proteins form the major cellular structural elements, are biochemical catalysts,and important regulators of gene expression. • Protein may be classified as of plant or animal origin, or by its constituent amino acids.

SOURCES • Protein makes up 20-36% by weight of pulses (legumes), 8-25% of nuts and seeds, 8-16% of cereals, 10-20% of meat and fish, 15% of eggs, 3.5% of milk and 1-3% of vegetables. • Plant protein sources provide 65% of the world supply of edible protein of which cereals (grains) (47% of total protein supply) and pulses, nuts and oil seeds (8%) are the major sources. • Intakes of plant protein vary little with economic development. Intakes of animal protein generally increase with increasing economic prosperity.

COMPOSITION • Protein is an essential human nutrient. Specifically, certain of its constituent amino acids are identified as essential, meaning that, like vitamins, the body is unable to manufacture them from other dietary constituents. • Proteins are complex molecules containing up to several thousand amino acids. Twenty-one amino acids are distinct;others are chemically modified during protein synthesis.

• Structural or fibrous insoluble proteins provide the framework for animal tissues and organs (hair, skin, cartilage, bone and tendons). Others include the semisoluble contractile proteins of muscle, enzymes, peptide hormones, proteins of blood (including haemoglobin and albumin), milk (casein and whey proteins), cell membrane proteins, the plasma lipidtransport system, other transport proteins, and proteins involved in DNA replication, transcription, and repair.

The functions of Protein • They are the components of body composition • Form some important substances such as Hemoglobin, Enzyme and some hormones etc. • Produce energy.1g protein can produce 16.7kj(4.0kcal)

FUNCTIONS • The characteristic functions of proteins are determined by the relative amounts and sequence of their constituent amino acids. All proteins turn over, that is they break down to constituent amino acids and are then resynthesized, although for the structural proteins this process is slow or minimal.

• Individual amino acids also serve as precursors for a range of metabolites such as neurotransmitters, pigments, amines, nucleic acids and various cellular metabolites. Many amino acids can be easily interconverted, and are dispensable and replaceable by other amino acids or nitrogen sources. • However eight (in adults) or nine (in infants) have structures that cannot be synthesized by humans; these are the essential amino acids.

Amino acid and essential amino acid • The distinction between dispensable (nonessential) and indispensable (essential) amino acid is strictly nutritional,inasmuch as am indispensable amino acid must be part of the diet,while a dispensable amino acid need not necessarily be present in food. By definition,an indispensable amino acid cannot be synthesized by the organism in question.

Indispensable amino acids • • • • • • • • •

Isoleucine(Ile), Leucine(Leu), Lysine(Ly), Methionine(Met), Phenylalanine(Phe), Tryptophan(Trp), Threonine (Thr), Valine(Val). Histidine(His) is essential amino acid for infant. Cysteine(Cys) and Tyrosine(Tyr) are conditionally essential amino acid or semiessential amino acid.

Reference protein • Reference proteins contain all the amino acids in the exact proportions needed for protein synthesis.Albumin (found in egg white) and casein (milk) are the closest examples.Other proteins are compared with these reference or perfect proteins.

Limiting amino acid • A limiting amino acid is the essential amino acid present in a protein in the lowest amount relative to its requirement for synthesis.Examples of proteins and their limiting amino acid are • Wheat limited by lysine • Meat and fish limited by methionine and cysteine • Maize limited by tryptophan. • Combining different protein-containing foods such as meat and the pulses ensures an adequate intake of all amino acids,that is protein complementation.

Metabolic need • This is a direct reflection of rates of metabolic pathways (e.g., protein deposition) that consume the nutrient in question and is fundamentally a function of genotype as well as the developmental and physiological state of the individual.

Dietary requirement • This is the quantity of the nutrient that must be supplied in the diet in order to satisfy the metabolic need; it includes factors associated with digestion, absorption, and cellular bioavailability.

Recommended dietary allowance(RDA). • This is the practical expression of nutritional recommendations. An RDA is designed explicitly to be applicable to populations rather than to individuals and thus attempts to account for variability among subjects in need and dietary requirement. RDAs are intended to prevent nutrient deficiency, and are often expressed as "safe levels." An RDA, so defined, is the intake that reduces the prevalence of nutrient deficiency to some desired proportion of the population while avoiding excessive intakes.

• Metabolic need
High-quality protein • The use of the term "high-quality protein" in the RDA indicates that dietary proteins differ in their nutritional quality. This reflects the differences in amino acid composition of proteins and the fact that the protein need is, in many respects, a surrogate for the sum of the needs for each amino acid. • In theory, the term "high quality" should reflect how closely the amino acid composition of dietary protein and the individual's needs for different amino acids match one another.

• This has led those concerned with farm animal nutrition to develop the concept of the "ideal protein," an ideal protein being defined as one with an amino acid composition that maximizes its productive utilization by the recipient animal. • In human nutrition, the term "high quality" is often taken to be synonymous with proteins of animal origin, usually milk or whole egg. However, assessment of the quality of a given dietary protein should start with a consideration of the amino acid needs of the individuals to whom it will be fed.

• The equation of "high quality" and "animal origin" is not necessarily correct for any stage of life other than perhaps early infancy. For example, it has been shown that relative requirements for different amino acids of preschool children are not the same as relative quantities of amino acids in egg and milk.

• The requirements of this population can be readily satisfied with mixtures of foods of vegetable origin. Indeed it is possible to prepare mixtures of proteins of plant origin (e.g., a cereal and a legume) that, for school-age children, have a higher biological value than mixed egg and milk diets.

Protein Digestion and Absorption • Digestion of dietary protein begins in the stomach with the action of the protease pepsin, which is secreted as an inactive proenzyme (zymogen). Activation occurs autocatalytically with the release of a small peptide fragment from the inactive precursor. The contribution of the gastric phase to overall protein digestion is mainly cleavage of dietary proteins to smaller polypeptides and accounts for <10% of total protein digestion in humans.The major site protein digestion is the small intestine.

• Here proteins of dietary origin (exogenous) as well as those of endogenous origin are cleaved to small peptides and free ammo acids. Endogenous proteins are secretions of the oral cavity (saliva), stomach, intestine, liver (bile), and pancreas. They include hydrolytic enzymes and proteins of cells desquamated during the normal turnover of intestinal mucosa. Endogenous protein may account for up to 50% of the total protein digested.14 The proportion will depend upon dietary protein intake.

• The intestinal proteases are also secreted as proenzymes from the pancreas. A brush border enzyme, enterokinase, which is released from the intestinal mucosa by the action of bile acids, activates trvpsinogen to trypsin by cleaving a hexapeptide. Trypsin in turn activates the other pancreatic proenzymes producing an array of activated proteases including endopeptidases, such as trypsin and chymotrvpsin, and exopeptidases,such as the carboxypeptidases. The end result of the action of these enzymes coupled with that of aminopeptidases from the brush border is mixture of free amino acids and short peptides, mainly dipeptides and tripeptides, which are readily taken up by the enterocyte.

• A number of transport systems exist for ensuring efficient absorption of the products of protein digestion. Well-defined carriers for the transport of acidic, basic, and neutral amino acids have been identified;

REQUIREMENTS • Humans require dietary protein to provide amino acids both for the synthesis of proteins during tissue growth and turnover and for conversion to the various metabolites that are derived from amino acids. Dietary amino acids need not match the composition of tissue proteins exactly. However, diets must provide the essential amino acids as well as sufficient amino acids or nitrogen sources to allow synthesis of the non-essential ones.

• Traditionally, the nutritional value (quality) of dietary proteins has been classified in terms of their ability to provide for tissue growth in rapidly growing rats; marked differences are observed between most animal proteins and individual plant-protein sources. With the exception of gelatin (from collagen), most animal dietary protein sources have an amino-acid composition similar to that of tissue protein. Cereal proteins tend to have lower levels of the amino acids lysine and tryptophan, and pulses contain lower levels of sulphur-containing amino acids. In combination, these differences tend to cancel each other out, so that mixtures of plant proteins allow similar body growth rates as animal proteins through provision of the appropriate balance of essential amino acids.

• Human growth is very much slower. so the nutritional demand for essential amino acids is much lower; moreover, contrary to the older view, there is little if any difference between the quality of protein of animal origin and that from plant sources when these include both cereals and pulses.

• There are currently no generally agreed values for the requirements for essential amino acids in the human diet (FAO/WHO, 1991). National agencies now stress that, in most mixed, nutritionally balanced diets, sufficient essential amino acids will be provided irrespective of the relative amounts of plant or animal protein sources (Department of Health, 1991).

• Recommendations for adults are specified as 0.75 g/kg in the UK (the RNI) and 0.8 g/kg in the USA (RDA), which is equivalent to about 9% total energy intake, with an upper limit recommended at 1.5 g/kg (about 18% total energy).

Functional and Metabolic Basis for Amino Acid Needs • Minimal needs for growth • Minimal needs for maintenance of body nitrogen equilibrium • Nonprotein aspects of maintenance amino acid needs

Minimal needs for growth • The composition of body protein should provide a firm basis for defining the quantities of individual indispensable amino acids obligatorily needed for protein deposition.The relative requirements of different essential amino acid,as measured by nitrogen balance trials,show a commonality among species and are similar to the composition of body protein

Minimal needs for maintenance of body nitrogen equilibrium

CONSUMPTION PATTERNS • The amount and type of protein consumed varies widely in different parts of the world. The most notable difference is in the ratio between protein of plant origin and protein of animal origin.

• Throughout the world, protein intake varies between 10% and 18% total energy. The average in Africa is 58 g (10% total energy) of which 79% is of plant origin. Consumption in Japan is 79 g (15.5% total energy), of which 47% is of animal origin. In a UK nutrition survey, intakes were 73.2 g (13% total energy), of which 64% came from meat, milk, eggs and fish, and 31% from cereals and vegetables. Consumption in North America is 110 g (1617% total energy), of which 66% is of animal origin.

• Intakes of total protein above 2 g/kg are rare, although some athletes consume up to 3 g/kg (30% total energy). Low intakes of protein are more common among vegetarians. For example, in the UK, 32% of female and 20% of male vegetarians, compared with only 5.8% of female and 3.0% of male omnivores, consume less protein than the RNI of 9% total energy (Jackson and Margetts, 1993). The amino-acid composition of mixed lacto-ovovegetarian diets is not markedly different from that of meat eaters.

Nutritional evaluation of protein in foods • Amount • Digestibility • Protein protein utilization (NPU) • Chemical score or Amino acid score(AAS)

Protein quality • Chemical score • Biological value • Net protein utilization

Protein energy malnutrion(PEM) • Kwashiorker • Marasmus

• Kwashiorkor in an african child showing edema and dermatosis (left) skin lesions (right)

Nutritional marasmus. showing extreme wasting in a child

Chapter 3 Lipids • Dietary fat consists mainly of a heterogeneous mixture of triacylglycerols (triglycerides) and makes up a substantial but variable portion of total energy intake. • many European countries, fat accounts for 40-45% of total energy in the diet. In the United States, ranging between 30% and 40% in Asia and Africa, fat provides only l5--25% of energy.

• A widely held belief is that excess dietary fat contributes importantly to several chronic diseases, such as coronary heart disease (CHD), stroke, diabetes mellitus, cancer, and obesity.

• Fat is a major nutrient and an important source of body fuel, and fat consists of a complex mixture of triacylglycerol molecules that can differ greatly from one another in their chemical and physical properties.

Classification of Lipids • Triglycerides • Phospholipids • sterols

Lipids Definition: a wide variety of chemical substances such as fat (TG), FA, and their derivatives, phosphalipids,glycolipids, sterols, and fat-soluble vits.

Dietary lipids:Fat constitutes ~90% . Function: Provide energy, carrier for fat-soluble vits, EFA as essential nutrients, cell structures, precursors of PG.

Property: Insoluble in water, soluble in organic solvents. The chemical and physical properties of fat are influenced by the FAs they contain. SFA<=10 C liquid SFA> 10 C solid RT PUFA liquid RT Insolubility: important for storage as energy and participation in membrane structure.

Function of Lipids • • • • •

Maintain body temperature Storage of fat Components of body Satiety Improve the properties of food such as color, flavor,smelling etc. • Produce energy:1g fat produce 39.7kJ(9.46kcal)

FAs: Basic formula: CH3[CH2]nCOOH n can be any number from 2 to 22 and is usually an even number. Classification: A) Chain length: Short chain: C2-4 Medium chain: C6-10 Long chain: C12-24 B) Saturation: (# of D.B.) Saturated : no D.B. Unsaturated: one D.B. Polyunsaturated: 2 or more D.B.

Essential Fatty Acid(EFA) • linoleic acid • linoleni acid

Function of EFA • Component of phospholipids,cell member • Precursor of prostaglandins • It is related to metabolism of cholesterol

Nomenclature: The DB in all of naturally occurring FAs are in cis configuration (H atoms are on the same side of the DB) e.g. H-C-(CH2)nCH3 CH3-(CH2)n-C-H H-C-(CH2)nCOOH H-C-(CH)nCOOH Cis trans The C atoms of FA are numbered from the carboxyl group (∆ numbering system) or lettered (ω or n numbering system)  numbering system (carboxyl side) 16 4 3 2 1 CH3(CH2)11 CH2CH2CH2COOH 1

13

C16:1 or C16:1, 9 CH3(CH2)5 C=CH CH2 (CH2 )6COOH

14 15 16

ω or n numbering system (ω -side)

C16:1, ω 7

Digestion and absorption Mouth: little or no lipid digestion Stomach: some lipase, but acidic environment w/o bile salt →no significant digestion Duodenum: the forceful contraction of stomach breaks up lipids into fine droplets (Ave D~100 Å) which are exposed to the solubilizing effects of BS. BS –powerful emulsifying agents, hydrophobic & hydrophilic sides Pancreas procolipase ⊕ Colipase bind to BS and Droplets [allow lipase to hydrolyze the TG droplets.

Trypsin Lipase

(covered by PL which displacing lipase from the droplets)]

Factors involved in lipid digestion:

* Contraction of stomach * Enzyme from pancreas ( lipase and colipase) * Bile salts

Digestion and absorption • Dietary triacylglycerols enter the gastrointestinal tract,where they come into contact with gastric and intestinal lipases. The latter is the major lipase, and it hydrolyzes the fat into free fatty acids and monoacylglycerols. • Fatty acids in positions sn-l and sn-3 are removed,whereas that at position sn-2 remains attached to glycerol. The solubilization of fatty acids in the gut is enhanced by the polar lipids of bile: bile acids and phospholipids, which promote the formation of expanded,mixed micelles that solubilize fatty acids and monoacyglycerols. These lipid products then pass by monomolecular diffusion into the mucosal cells of the small intestine.

Lipid Transport:

Lipoprotein: Absorbed lipids are made water-soluble for transport by blood plasma by their incorporation into lipoproteins CM : produced by intestinal mucosa , rich in TG &Chol VLDL: secreted by the intestinal mucosa HDL: liver , small intestine muscle LDL: VLDL heart TG LPL (in LP)

FAs passive diffusion

energy kidney cell re-esterified CE platelets TG (energy storage) phospholipids cell membrane

Most circulating FAs are from lipolysis of TG in adipose tissues during fasting, FAs transported in the form of complex w/albumin.

Fatty acid • Saturated Fatty acid; • Monounsaturated fatty acid • Polyunsaturated fatty acid cis-fatty acid and trans-fatty acid

Saturated Fatty acid • • • • •

Stearic acid( 18:0) Palmitic acid(16:0) Myristic acid(14:0) Lauric acid(12:0) Medium-chain fatty acid(8:0 and 10:0)

monounsaturated fatty acid • Oleic acid(cis-18:1) • Elaidic acid (trans- 18:1)

polyunsaturated fatty acid; • n-6 fatty acids:Linoleic acid(18:2) • n-3 fatty acids:Linoleic acid (18:3) Eicosapentaenoic acid (EPA)(20:5) Docsahexaenoic acid (DHA)(22:6)

• The predominant monounsaturated fatty acid is oleic acid (cis-18:l n-9). The term "cis-”indicates that the double bond is in the cis cofiguration, and the term "n-9" means that the double bond is located nine carbon atoms from the terminal carbon.Another monounsaturated fatty acid is elaidic acid (trans-l8:1n-9). The trans configuration of the double bond forms during the catalytic hydrogenation of poIyunsaturated fatty acids. Other trans monounsaturates having double bonds at other locations along the carbon chain are also produced by hydogenation.

Phosphorous • Lecithin • Cephalin or kephalin CH2-OOCR2 CHCH2-OOCR1 CH2-OOCR3

Sterols • Cholesterol

Cholesterol Metabolism : Ch found in all animal tissues. Eggs—only common food rich on ch (252mg/large egg). Body chol present all kind of cells of body. Esp. Brain, nervous system, connective tissue, muscle Blood chol only ~8% of total body chol. Function : ★ Major constituent of all cell memb. ★ ~50% of myelin which surrounds the nerves is ch (ch is necessary for proper nerve conduction and brain function) ★ precursor of BS ★precursor of steroid hormones ★ essential components of plasma LP ★ precursor of vit D

Synthesis: Except the mature red blood cells, all cells can synthesize ch in human. Site: liver & intestine C source: AcCoA (CHO,FA,PRO.) In human de novo synthesis of chol >dietary intake (>30 steps) AcCoA HMG CoA * mevalonate phosphomevalonate farnesylpyrophosphate chol HMG CoA reductase—rate limited enzyme can be inhibited by dietary chol in liver (not in small intestine). Chol homeostasis: Bile acids Dietary chol steroid hormones De novo synthesis Chol excretion in the feces Dietary factors affect ch metabolism: dietary ch, fat, cal , pro, CHO, fiber etc.

EFAs Definition: EFAs are those that cannot be biosynthesized in adequate amounts by animals and humans and which are required for growth, maintenance, and proper functioning of many physiological processes. They have one or more DB situated within the terminal seven carbon atoms (counting from the ω end ) and can not be made de novo. Therefore must be supplied in the diet. * Linoleic acid (C18:2, ω 6,9)--n-6  Linolenic acid (C18:3, ω 3,6,9)--n-3  Arachidonic acid (C20:4, ω 6,9,12,15) –can be converted from linoleic acid *only EFA

Functions a).Stimulation of growth b).Maintenance of skin and hair growth Maintains the integrity of epidermal water barrier,. w/o EFAs severe water loss from the skin; c).Regulation of chol metabolism Formation of bile acids from chol require EFA; synthesis of phosphatidyl choline—a constituent of HDL, which in turn break down the chol transport process prevent TG & chol accumulation in liver. d).Maintenance of cell membrane integrity Cell secretion, signal transmission depend on memb. fluidity; n-3 FAs-- important components of structural lipids in many tissues, e.g. brain, retina.

Deficiency: Most common cause of EFAs deficiency in human in all age group—long term of fat free; Parenteral nutrition (PN); Low birth weight infants have limited body stores of EFAs easy to be deficiency. Dietary requirements: U.S. linoleate in diet 10 g/d Food source: Vegetable oil, e.g. corn oil, soy bean oil, safflower oil, sunflower oil. Arachidonic—foods animal origin

Fat consumption and balance of FAs in the diet There is close relation between dietary fat and obesity, heart disease, cancer. Plasma [chol] >5.17 mmol/L risk for AS …………….. >6.20 mmol/L high risk for AS for them , the recommended fat consumption: Total fat <30 en% SFAs <10 en% PUFA <=10 en % MUFA 10~15 en % the ratio of P:M:S should be 1:1:1

Sources of Lipids • Animal • Plant oil

Chapter 4 Carbohydrates (CHO) • General formular: (CH2O)n

Definition • CHO are polyhydroxy aldehydes, polyhydroxy ketones, or compounds that can be hydrolyzed to them.

Classification of carbohydrates • saccharide （ 1-2monosaccharide ）： monosaccharide(glucose,fructose and galactose,ribose,deoxyribose,xylose etc.); disaccharide(sucrose,lactose,maltose etc.) • oligosaccharide （ 3-9monosaccharide ） ： raffinose and stachyose) • polysaccharide （ 10monosaccharide ） ： starch,glycogen and fibre 。

Classification A).Monosaccharides—are simple sugars which cannot be broken down into smaller molecules by hydrolysis. B).Disaccharides—can be hydrolyzed to give two monosaccharide units. C).Oligosaccharides—are polymers made up of three to ten monosaccharide units. D).Polisaccharides are polymers with many monosaccharide units.

Major CHO in the human diet: Disaccharides: Sucrose (cane sugar) lactose (milk sugar) Polysaccharides starches: amylose : consists of 250-300 glucose units linked by α -1,4 glucosidic bonds, straight chain. amylopectin:α -1,4 glucosidic bonds, about one α -1,6 glucosidic bonds, for thirty α -1,4 glucosidic bonds,(branched type, 80-90%of dietary starch). * Starches (glucose polymers) and their derivatives are the only polysaccarides that are digested to any degree in the human GI tract. * Glycogen resenbles amylopectin in structure but has a higher degree of branching.

Digestion: Starch: salivary amylase (begins in the mouth) pancreatic amylase (the bulk of starch digestion in the small intestine ) intestinal amylase (minor contribution ) This process yields glucose as well as three oligosaccharides— maltose, a disaccharides, maltotriose, a trisaccharides, and α -limit dextrins, which contain 8 glucose moieties on the average. Oligosaccharides: from above or diet; Oligosaccharidases: lactase, maltase, sucrase, α -dextrinase-epithelial brush border Undigestible CHO: metabolize by the Bacteria are present in the lower ileum and colon; products: hydrogen (H2), methane (CH4), and CO2, SCFA. May cause--diarrhea, cramps (“gas pains”), bloating.

Principal end products of CHO digestion in the intestinal lumen: α -limit dextrin maltotriose G G

G

G

sucrose maltose G lactose

G

G G

G

Ga

G

G

G

F

Digestion of CHO Source Enzyme salivary α -amylase linkage,produing dextrins, maltotriose and

Substrate starch

Catalytic function or products hydrolyzes 1,4α α -limit maltose.

Exocrine Pancreas Intestinal Mucosa

α -amylase maltase Lactase Sucrase

starch maltose maltotriose lactose sucrose

α -limit dextrinase

α -limit dextrins

same as above glucose Ga & G F&G

G

Mechanism of absorption: Glucose and other monosaccharides are hydrophilic, to pass through the hydrophobic lipid cell membrane of the intestinal epithelial cell, need the carrier molecule in an active energy-consuming process:

1.Glucose and galactose, for example, share a carrier transport system and compete for access to it. This system is Na+-dependent, and for this reason, has been termed the Na+ co transport mechanism. 2.Fructose is absorbed along concentration gradient. Although mechanism does require a specific carrier, it does not energy and, thus, is termed facilitated diffusion.

this consume

Factors determining the blood glucose level:

The balance between the amount of glucose entering the blood stream and the amount leaving it. The principal determinants : dietary intake; the rate of entry into the cells of muscle, adipose tissue, and others; the glucostatic activity of the liver; Ingested glucose : 5% → glycogen in the liver. 30-40% → fat. the remainder→ metabolized in muscle and other tissues.

Blood glucose homeostasis Diet

amino acids glycerol liver

intestine

kidney

Urine (when BG>180mg/dl)

lactate

Blood glucose

brain

fat

Muscle and other tissues

Function of dietary • • • •

Improve intestine Control body weight and lose weight Decrease glucose and cholesterol in serum Prevent from cancer

Functions of CHO • • • • •

Provide and store energy Components of bogy Sparing protein action by gluconeogenesis Antiketogenesis Provide dietary fiber

Function: 1. to provide a source of energy; (~50-60 en % in the US). Esp. Brain& RBC 2.body component; e.g.glycolipid, DNA, RNA, lycoprotein. 3.Sparing protein; 4.Antiketogenesis;

Source of CHO • Plant :corn, wheat, rice • Amimal :liver

Major source: plant food, diary food, meat, food additives. RDA: minimum 50-100mg/d 50mg/d can antikosis; 100mg/d can prevent dehydration. *short term CHO free diet is not harmful.

CHO intolerance It is characterized by malabsorption that leads to symptoms, particularly diarrhea, with excretion of acidic stools and carbohydrate in the feces following ingestion of sugars. It can be due to a defect in digestion and/or absorption of dietary carbohydrate. Di-, oligo-, and polysaccharides that are not hydrolyzed by amylase and/or small intestinal surface (brush border) enzymes cannot be absorbed; they reach the lower tract of the intestine which contains bacteria. Microorganism can break down and anaerobically metabolize some CHO resulting in the formation of SCFAs, lactate, H2, CO2, and CH4. The presence of osmotically active CHO and fermentative products within the lumen is associated with intestinal secretion of fluid and electrolytes until osmotic equilibrium is reached. These products on the intestinal motility and cramps, because of intraluminal pressure and distention of the gut, or because of the direct effect of degradation products on the intestinal mucosa. Some intestinal mucosal cells along with disaccharidases may be lost.

Disaccharidases deficiency: Common in human, due to a single or several enzymes for a variety of reasons : e.g. genetic defect, injuries to mucosa, or physiological decline with age. Patients suffering or recovering from a disorder cannot drink or eat significant amount of dairy products (lactose) or sucrose without exacerbating the diarrhea. Lactase deficiency most commonly observed in human (milk intolerance) a) inherited deficiency, which is relatively rare; b) secondary low lactase activity, damage of the small intestine c) primary low-lactase activity is a relatively common syndrome, agerelated decline in lactase activity

Nutriton therapy: ◆ reducing or avoiding lactose intake (milk and dairy products); ◆ pretreating milk with lactase derived from bacteria ◆ ingesting only lactose-treated dairy products such as Lactaid or Dairy Ease. !!! Individuals who avoid all products containing lactose will not meet their daily calcium requirement. Calcium supplementation of 800 to 1200 mg/d is necessary for these patients. Pregnant and lactating women and the elderly require higher levels , depending on their intake of nondairy calcium sources.

Dietary Fibre • Soluble fibre :pectin,gum ,mucilage and hemicellulose • Insoluble fiber:cellulose,some hemicellulose, lignin

Dietary fiber: Definition: those plant constituents which are resistant to digestion by secretions of the human GI tract.

Food sourses: All food of vegetable origin, but in variable quantities. Whole grain cereals are a major source. Average contents: Whole wheat:12.8%; White flour: 3.3%; Wheat bran 42.4%; Corn bran 88.8%;White rice 4.1%; Dry bean, soy bean >4%; Roasted nuts 2.3-6.2% Most fruit & vegetables 0.5-1%;

Components of DF Major nonstarch polysaccharides (including celluloses, hemicelluloses, pectins, etc.). Cellulose (unbranched polymers of β 1,4 bond) most abundant and best known component of fiber, in all pant cells, rich in oats and barley.

Physicochemical and biologic actions of fiber Type of fiber Cellulose β 1,4 bond

Chemistry Physical property Biologic action linear G polymers hydrophilic, ↓ transit time, H2O insoluble ↑stool bulk

Hemicelluloses branched polymers of pentose & hexoses H2O insoluble

hydrophilic, ↓ transit time, ↑stool bulk

Pectins mixture of colloidal can form, ↓rate of small viscous solutions intestinal absorption galacturonic acid water soluble, (glucose, bile acids, linked to sugars gel-forming plasma Chol) binds bile salts

Polysacharides,

transit time—the time necessary for a substance to move through the entire GI tract and pass out in the feces. It is shorten by ingestion of increased dietary fiber.

Fiber and disease • • • • •

Constipation Colon cancer Hyperlipidemia DM Obesity

1. Constipation—elderly people,

Hemicelluloses and cellulose hydrophilic property→ ↑stool bulk and weight. 1 g of extra DF →↑ stool weight by 3-9g. The stool weight in low fiber intake population is 80-200g/d; ……………………high………………………….400-500g/d. Insoluble fiber especially wheat bran has the greatest effect on stool wt.

2. Colon cancer—the 2nd cause of cancer mortily

in the U.S.

Protect against cancer in several ways. 1). ↑Water content and fecal bulk→dilute the potential carcinogens or cocarcinogens in the colon. 2). ↓the transit time→↓time of mucosa exposed to the toxic materials. 3). ↓the production of carcinogen by altering the bacterial flora or their functional activities. 4).absorb the toxic material →↓their availability to the lining of the colon. 5). The production of SCFA→↓colonic pH→conversion of bile acids to potential carcinogens; →limit the uptake of ammonia by epithelial cells →energy for bacterial growth→help inactive toxic substances. →antineoplastic.

3. Hypolipidemia Hypolipidemic effect: soluble fiber. Fiber → ↓transit time →↓fat, chol absorption →binding bile salts, chol →↓ fat, chol digestion, absorption → binding bile salts→↑ chol excretion.

Diabetes DF →↓glucose absorption and levels of blood glucose and insulin. 1). ↑the peripheral sensitivity to insulin 2). ↑ The number of insulin receptors on circulating monocytes

Obesity Obesity—high fiber →↓bw. 1). Displace available nutrients from the diet. 2). It requires chewing which slows down food intake and promotes a feeling of satiety→↓food intake 3). ↓absorption efficency of the small intestine. Overconsumption of fiber ↓vit. Mineral (Zn, Fe, Mg, Ca) absorption.

Fig 1 Annual Ratio Trends for Old People Aged at 65 and Over (Management and Coordination Agency, September 2002) % 30 25 20 15 10 5 0 1970

1980

1990

2000 Year

2010

2020

2030

Fig 2 A Number of Old People who Need Assistance

x ten thousands

(Health and Welfare White Paper 1997)

600 500 400

bed-ridden dementia infirmity

300 200 100 0 1,993

2,000

2,010

year

2,025

Chart 1 Lifestyle-Related Disease Life-style related disease in England Maladie de comportement in France Zivilisationskrankheit in German Valfardssjukdomar in Sweden

Table 1 Living Practices concerning Lifestyle-related Diseases

Eating habits Hypertension followed by cerebral apoplexy; Obesity followed by hyperlipidemia, hyperglycemia; Type II diabetes; Colon cancer; Hyperuricemia Exercise insufficient

Obesity; Hyperlipidemia; Type II diabetes; Hypertension

Smoking

Lung squamous cell carcinoma; Lung emphysema; Chronic bronchitis; Periodontosis; Circulatory diseases; Stomach cancer

Drinking

Alcoholic liver disease; Esophagus carcinoma 　

Diagnostic Standards for Obesity, Hypertension, Hyperlipidemia, Hyperglycemia, Osteoporosis and Uricemia Table 2

Diseases

Unit

Obesity

BMI

Hypertension

mmHg

Hyperlipidemia

Item

Normal

Marginal

Pathological

19.8-24.2

24.2-26.4

> 26.4

diastolic systolic

90-140 < 90

140-160 90-95

> 160 > 95

mg/dl

total chol. LDL chol. total fat

< 200 < 140 < 150

200-220 no disease no disease

> 220 > 140 > 150

Hyperglycemia

mg/dl

fasting glucose

< 126

126-160

> 160

Osteoporosis

SD

bone mineral

< -1.5

-1.5- -2.5

> -2.5

Hyperuricemia

mg/dl

<6

6-8

>8

Table 3 Worse Following Lifestyle-Related Disease Lifestyle

Mild symptoms

Severe symptoms

Intense pain

After effect

High salt diet

mild hypertension

*severe hypertension *atherosclerosis

*cerebral haemorrhage *cerebral infarction

*hemiplegia *phasia *dementia

High fat diet

hyperlipidemia obesity

*hyperlipidemia

*coronary infarction

*restricted activity *recurrence

Less exercise

obesity less bone density hyperglycemia

*hyperlipidemia *osteoprosis *type II diabetes

*fracture

*restricted excercise

Hyperalimentation

obesity hyperglycemia hyperuricemia

*type II diabetes

*necropathy *diabetic nephropathy *diabetic retinopathy

*dismember *hemodialysis *blindness

Drinking

hyperuricemia

*gout

*gouty attack *nephropathy

*gouty attack *nephropathy

Smoking

early neoplasm

*malignant neoplasm

*intense pain

*extirpation and terminal care

Table 4 Primary, Secondary and Tertiary Care for Disease Prevention Goals

Target

Primary Normal (lifestylerelated disease):healt hy life span

Care aiming at prevention

Guidance for exerciseParticipant in medical care & nutrition

Hypercholesterolemia; Public health guidance; Managerial nutritionist; Public Hypertension; Community and school health nurse; Health and Hyperglycemia; guidance; Control of exercise instructor Osteoporosis; Diabetes; exercise; Control of Obesity; Early neoplasm school lunch;

Secondary Mild case Cerebral apoplexy; Guidance of meals for (adult Coronary infarction; outpatient; Diet diseases): Diabetes; Cancer; Fracture; guidance by early Derangement educational detection & hospitalization treatment

Doctor; nurse; Expert of clinical examiner; Hospital dietitian

Tertiary Serious Cerebral apoplexy; Diet guidance for (inpatient): case Infarction; Cancer; Diabetes; inpatient; End stage prevention of Diabetic nephropathy; diet supplementation death Blindness; Bed-ridden

Doctor; Orderly; Physical therapist; Terminal orderly

Fig 3 A Number of Hospitalized and Ambulant Patients per 100,000 (Health, Labour and Welfare, Patient Survey) 700 600 500 400 300 200 100 0 1950 1960 1970 1980 1990 2000 2010

Hypertension Derangement Neoplasm Heart disease Diabetes Liver disease Tuberculosis Cerebrovascular

Fig 4 Striking Increase of Diabetes

250 200 150 100 50 0 1960

1970

1980

1990

2000

Fig 5 Annual Distribution Trends for Obese People (BMI> 25)

Women

Men 35 30

%

25

%

20 15 10 5 0 1975

1980

1985

1990

1995

2000

35 30 25 20 15 10 5 0 1970 2005

1980

age at 20

1990

2000

age at 30

Fig 6 Annual Distribution Trends for Leptosomatic People (BMI< 18.5) Men

Women

30 25 15 20 10 15 10 5 5 0 0 1970 1980 1990 2000 2010 1970 1980 1990 2000 2010 %

%

20

age at 20 age at 40

age at 30 age at 50

age at 20 age at 40

age at 30 age at 50

Fig 7 Blood Pressure with Age M en 70

64.5

60

55.6

50 43.7

41.4 40 %

34.8

30 20.7 20 11.5 10 2.5 0 Total

15-19

20-29

30-39

40-49

50-59

60-69

age over 70

W om en 70 60.7 60 51.7

%

50 40

36.9 31.9

30 17.5

20 10

4.4 0.7

0

0 Total

15-19

20-29

30-39

40-49

50-59

60-69

ageover 70

Fig 8 Distribution of People Having High Blood Cholesterol (>220 mg/dl)

Men

35 30 2525. 1 %

33. 2 29. 9 26 25. 7

20 15

Women

13. 9

35 30 2525. 1

20 17. 3 % 15

33. 2 29. 9 26 25. 7

13. 9

17. 3

10

10

5

5

0 Total 30- 39 50- 59 over 70

0 Total 30- 39 50- 59 over 70

Fig 9 Distribution of People Having High Blood Glucose Level (> 110 mg/dl)

50 41. 7 29. 4 % 22. 67 .9 15. 3 16.8 8. 1 0 Tot al 30- 3950- 59 over 70 M en

%

50 41. 5 33. 4 2 2 .7 22. 3 4 .5 8. 29. 6 0 Tot al 30- 39 50- 59 over 70

Fig 10

Fig 11 Distribution of People Having Exercise Twice a Week, More Than 30 Min per Once and Continuing More Than One Year

45 38. 3 42. 940 40 39. 5 35 35 30. 1 31. 3 30 31. 9 27. 4 30 29 28. 9 25 22. 6 25 23. 222. 6 19. 7 % 20 % 20 15 15 15 10 10 5 5 0 0 total 30- 39 50- 59 over total 30- 39 50- 59 over 70

Fig 12 Distribution of People Smoking Regularly

70 60

70 60. 8 56. 6 55. 1 54. 1

5047. 4 40 30 20 10 0 Tota

60 50

40 37 29. 4 30 20. 9 20 18. 8 13. 6 11. 5 10. 4 10 6. 6 4 0 30- 39 50- 59 over Tota 30- 39 50- 59 over 70 70

Fig 13 Distribution of People Drinking Alcohol Three Times a Week, and More Than 180 ml Sake and 650 ml Bear a Day

Men

Women

70

70 61.5

60 53.3

50.8

60

56.9

55.8

50

50 38.4

40 %

%

40 27.8

30

30

20

20

10

10

14.1 9

8.4

11.5

9.8

7.3 3.3

0

0 Total

20-29

30-39

40-49

50-59

60-69

age over 70

Total

20-29

30-39

40-49

50-59

60-69

age over 70

Fig 14 Annual Distribution Trends for People who Do not Have Breakfast

Total 12 10

%

8 6 4 2

Men

W omen

Fig 15 Annual Distribution Trends for Fat-Derived Energy in Total Energy Intake 100% 90% 80% 70%63.1

61.5

60.4

59.2

57.6

57.5

57.4

57.7

57.5

57.5

60%

Carbohydrate Fat Protein

50% 40% 30% 22.3 20%

23.6

24.5

25.3

26.4

26.5

26.6

26.3

26.5

26.5

10% 14.6

14.9

15.1

15.5

16

16

16

16

16

15.9

0% 1975

1980

1985

1990

1995

1996

1997

1998

1999

2000

Fig 16 Annual Distribution Trends for Animal-, Plant- and Fish-Derived Fat Intake Animal

60 50

g

40

6 28.3

5. 6

5. 6

5. 7

28.7

29.3

29.6

22

21. 6

Plant

Fish

5. 8

5. 8

6. 1

6

5. 9

30.2

29.7

29.6

28.7

28.9

30 20 10 0

20. 9 21. 3

24

23. 5 23. 6 23. 2 23.

Fig 17 Annual Calcium Intake Trends

700 600 500 400 300 200 100 0 1940

1960

1980

2000

Fig 18 Annual Salt Intake Trends

15 14

g/day

13. 5 13 12 11 10

13. 2 12. 9 12. 1

12. 5

12. 9 13 12. 12. 7 12

Table 5 Annual Food Intake Trends (g/d/capita) 1975

1980

1985

1990

1995

1998

1999

2000

Cereals: rice :wheat Potatoes Fats & Oils Pulses

248 90 60 15 70

225 91 63 16 65

216 91 63 17 66

197 84 65 17 68

167 93 68 17 70

164 90 71 16 72

162 89 67 16 70

160 94 64 16 70

Green vegetables Other vegetables Fruits Algae Sugars

48 198 193 4 14

51 200 155 5 12

73 187 140 5 11

77 173 124 6 10

94 196 133 5 9

87 186 115 6 9

94 196 119 5 9

95 194 117 5 9

Beverages & spices Confectionaries Fish & Shellfishes Meats Eggs Milks

119 29 94 64 41 103

109 25 92 67 37 115

113 22 90 71 40 116

137 20 95 71 42 130

190 26 96 82 42 144

193 24 95 77 40 135

185 23 94 78 40 37

182 22 92 78 39 127

Chart 2 Comparison of Health and Welfare Statistical Survey with Epidemiological Study Statistical Survey: Data of birth, death, diseases etc reported to municipals and wards from medical facilities.

Epidemiological Study: Investigation on health condition, diet , exercise and etc in freely living people.

Fig 19 Epidemiological Studies in Hisayama on Vascular Diseases Population: 7,50 Occupation: farmer Start of study: 1961 Aim: prevention from lifestyle-related diseases Age of participant > 40 Analyses of data Group I: 1961-1969 Group II: 1974-1982 Group III: 1988-1996 Autopsies: > 80%

Hisayama-machi, Fukuoka

Table 6 Annual Crisis Trends for Vascular Diseases (number/1,000 per year) Vascular diseases Cerebral apoplexy infarction hemorrhage subarachnoid hemorrhage Ischemic heart diseases infarction sudden death *P< 0.05 vs I group

I group

II group

III group

1961-1969

1974-1982

1988-1996

10.5 7.0 2.3 0.9

5.0* 3.7* 0.8* 0.5

4.7* 3.1* 1.0* 0.7

2.1 2.0 0.1

1.9 1.6 0.3

2.3 1.7 0.6

Table 7 Incidence of Hypertension, Use of Antihypertension Drug and Annual Blood Pressure Trends Group

Number of subjects

Incidence of hypertension (%)

Antihypetension drug user (%)

Blood pressure (mmHg)

Men I II III

705 855 1110

28 24* 23*

10 37* 62**

175/96 167/91* 157/87**

Women I II III

913 1183 1527

24 24 22

11 35* 70**

179/94 173/89* 161/82**

Age is adjusted. *P<0.05 vs Group I. **P<0.05 vs Group II.

Fig 20 Annual Incidence Trends for Metabolic Diseases (Obesity, Hypercholesterolemia HC, Impaired Glucose Tolerance IGT)

M en

W omen

1961 1974 1988

1961 1974 1988

50

50

40

40

30 %

%

20 10 0

30 20 10

O be se

HC

IG T

0

O bese

HC

Obesity BMI> 25; Impaired glucose tolerance IGT> 220 mg/dl

IG T

Fig 21 Annual Incidence Trends for Hypercholesterolemia accompanied with or without obesity

Men

W om en

60

60

50

50

40 Obese (-) Obese (+)

% 30 20

40 %30

10 20

0 1961

1974

1988

1961 1974 Obese (-) Obese (+)

654 19

829 51

1988 951 126

10 0

1961 1974 Obese1961 (-) Obese (+)

778 62

1988

1010 1974 1210 131 205

1988

Fig 22 Comparison of Annual Intakes Trends for Selected Foods between National Nutrition Survey and Hisayama Study

Ri ce 120 100 80 60 40 20 0

Meats

400 300 200 100 0

65 85 94 65 85 94 Nati onal Hi sayam a An intake from obtained from the National Nutrition Survey in 1965 is taken as 100. Nati onal Hi sayam a

Fig 23 Polymorphism of Aldehydedehydrogenase gene (ALDH2) and its Effect on Alcohol Consumption

Wild type (ALDH2·1) ACT GAA GTG AAA ACT GTG AGT GTG G….. Thr

Glu

Val

Lys

Thr

Defficient type (ALDH2·2) ACT AAA GTG AAA ACT GTG AGT GTG G….. Thr

Lys

Val

Lys

Thr

Metabolism of alcohol Alcohol

Acetoaldehyde

Alcohol dehydrogenase

Acetic Acid

ALDH

TCA Cycle

Table 8 Inheritance of a Particular Single Nucleotide Polymorphism Due to Lifestyle during Evolution Genes & polymorphism

Characteristics during evolution

Alcohol sensitive gene *Aldehydedehydrogenase (ALDH2·1) (ALDH2·2)

Black: consumed fruits fermented in tropical area. Caucasoid: depended on a fermented food during a long winter. Mongoloid: consumed fresh fruits.

Starvation resistant gene *Leptin receptor (exon 6, N223R etc) *Uncoupling protein β 3 Adrenergic receptor (W64R)

Caucasoid: depended on house hold animals during starvation. Mongoloid: depended on plant foods.

Salt sensitive gene *Angiotensinogen (T173K) *Angiotensin converting enzyme (R173K) *Aldosteron synthetic enzyme

Ape, Black and Mongoloid: lived in salt-poor area. Caucasoid: obtained salt from animals.

Fig 24 Starvation Resistant and Hypertension Sensitive Genes in Response to Lifestyle

LERP Thyroid gland

leptin noradrenalin

T3

Brown adipocytes

β 3 AR

β 3 AR

leptin

UCP3

UCP2

UCP1

PPAR2 γMuscle

PPAR2γ White adipocytes

Pancreas

TNFα adiponectin

insulin Diabetes

angiotensinogen

Obesity Atherosclerosis

Hypertension

Table 9 Different Lifestyles between Japan and the West Items Adequate energy intake Major foods cereals meats milks fish & shell Eating habits Agriculture Type of disease Genes

Japan

USA, Europe etc

2,200 Kcal 3,000 Kcal rice, fish wheat, meats, milks 459 g 258 g 91 g 305 g 162 g 659 g 187 g 50 g boiling, cooking, bread, meats, milks fermentation rice, root vegetables Wheat, vegetables, Hypertension, stock-farming stomach cancer Coronary infarction, lung cancer Caucasoid Mongoloid

Table 10 Effect of Walnut Consumption on Serum Cholesterol in Japanese, Spanish and American

Country Japan

Spain

USA

Subjects Healthy men & women

Background diet Average Japanese diet

Mild hyperlipidemic men Mediterranean diet & women Healthy men

NCEP Step I diet

Results

References

Lowering LDL Europ. J. Clin. cholesterol Nutr. 2002 Lowering LDL Ann. Intern. Med. cholesterol 2000 Lowering LDL New Eng. J. Med. cholesterol 1993

Conclusion • Lifestyle differs among countries, so that any recommendations related to health-promoting diet that was obtained in the West should be evaluated carefully to meet each countries demand. • It is urgent to examine systematically a role of diet and genetic polymorphism in prevention from lifestyle-related diseases. • It is necessary to increase consumption of rice to approximately 220 g/day.