Composition of an adequate diet.

1. Composition of an adequate diet

2. W h a t i s N u t r i t i o n ?W h a t i s N u t r i t i o n ?
Utilization of foods by living organismsUtilization of foods by living organisms
The process of utilization is biochemicalThe process of utilization is biochemical
Human nutrition has three types:Human nutrition has three types:
– UndernutritionUndernutrition
– Optimal nutritionOptimal nutrition
– OvernutritionOvernutrition

3. N u t r i e n t s a n d D i e tN u t r i e n t s a n d D i e t
Nutrients are the ingredients of foodNutrients are the ingredients of food
needed for normal functioning of the bodyneeded for normal functioning of the body
Nutrients provide energy for various bodyNutrients provide energy for various body
functionsfunctions
Quality (what food items) and quantityQuality (what food items) and quantity
(how much nutrients) are important for(how much nutrients) are important for
maintaining good healthmaintaining good health

4. T y p e s o f N u t r i e n t sT y p e s o f N u t r i e n t s
Two types:Two types:
– MacronutrientsMacronutrients
– MicronutrientsMicronutrients

5. M a c r o n u t r i e n t sM a c r o n u t r i e n t s
 Nutrients needed by the body in large amountsNutrients needed by the body in large amounts
are calledare called macronutrientsmacronutrients
 Three types of macronutrientsThree types of macronutrients
– ProteinsProteins
– CarbohydratesCarbohydrates
– FatsFats
 Macronutrients provide energy and buildingMacronutrients provide energy and building
blocks of proteins, carbohydrates and fatsblocks of proteins, carbohydrates and fats

6. M i c r o n u t r i e n t sM i c r o n u t r i e n t s
Nutrients needed by the body in smallNutrients needed by the body in small
amounts are calledamounts are called micronutrientsmicronutrients
Major types of micronutrientsMajor types of micronutrients
– VitaminsVitamins
– Minerals / trace elementsMinerals / trace elements
Required for maintaining normal health andRequired for maintaining normal health and
preventing various diseasespreventing various diseases

7. N u t r i e n t s f r o m D i e tN u t r i e n t s f r o m D i e t
 Proteins, carbohydrates, fatsProteins, carbohydrates, fats
 Essential fatty acidsEssential fatty acids
 Essential amino acidsEssential amino acids
 VitaminsVitamins
 MineralsMinerals
 Dietary fibersDietary fibers
 WaterWater

8. Four main Dietary Reference Intake categories

9. E n e r g y C o n t e n t o f F o o dE n e r g y C o n t e n t o f F o o d
Much of the food we eat is converted toMuch of the food we eat is converted to
ATP and other high-energy compoundsATP and other high-energy compounds
This energy is used for biosyntheticThis energy is used for biosynthetic
pathways, muscle contraction, nervepathways, muscle contraction, nerve
impulse, etc.impulse, etc.
Energy content of food is measured inEnergy content of food is measured in
calories (Kilocalories)calories (Kilocalories) of heat energyof heat energy
released by combustion (burning) of thatreleased by combustion (burning) of that
foodfood

10.  Small calorie (cal) is the energy needed to increase 1
gram of water by 1ºC at a pressure of 1 atmosphere.
 Large calorie (Cal) is the energy needed to increase 1 kg
of water by 1ºC at a pressure of 1 atmosphere.
 Large calorie is also called food calorie and is used as a
unit of food energy.
 The energy in large calories (Cal) is equal to the energy in
small kilocalories (kcal):
E(Cal) = E(kcal)
 Example
 Convert 6 kcal to large calories:
E(Cal) = 6 kcal = 6 Cal

11. E n e r g y E x p e n d i t u reE n e r g y E x p e n d i t u re
 Depends on four factors:Depends on four factors:
– Surface area of the body (height and weight)Surface area of the body (height and weight)
The greater the surface area the greater theThe greater the surface area the greater the
heat lossheat loss
– AgeAge
Growth and lean muscle massGrowth and lean muscle mass
Infants have higher basal metabolic rateInfants have higher basal metabolic rate
(rate of energy utilization in resting state)(rate of energy utilization in resting state)

12. – SexSex
Women have lower BMR than menWomen have lower BMR than men
– Activity levelActivity level
Exercise increases energy expenditureExercise increases energy expenditure

13. Recommended Energy IntakeRecommended Energy Intake
Sex Age Weight (Kg) Avg. Energy
Needs (kcal)
Men 23–50 70 2900
Women 23–50 55 2200
Pregnant - - +300
Lactating - - +500

14. Some Definitions
Omnivorous:Omnivorous: eat both meateat both meat
and vegetablesand vegetables
Carnivorous:Carnivorous: eat meat onlyeat meat only
Herbivorous:Herbivorous: eat vegetable,eat vegetable,
grass onlygrass only

15. Vegetarianism - Definitions
 Lacto-ovo vegetarian:Lacto-ovo vegetarian: A vegetarian who
consumes eggs (ovo) and milk (lacto)
 Lacto vegetarian:Lacto vegetarian: Does not eat eggs, meat,
poultry or fish/seafood of any kind, but does
consume dairy (lacto) products
 VeganVegan: A strict vegetarian who does not eat
animal products, meat, fish, poultry, eggs or
dairy

16. Vegetarian diet and disease
(Research results)
 -Lower Body Mass Index (BMI) - contain less fat, saturated fat, and
cholesterol
 - contain vegetables and fruits high in antioxidants and that contain dietary
fiber and phytochemicals.
 - have lower blood cholesterol levels
 - are less likely to develop heart disease
 - have lower weight
 - are less likely to have high blood pressure
 - have lower rates of cancer

17. Dietary guidelines – more about RDA
 Recommended Dietary Allowance (RDA)
– Developed during the 1940’s
– Prevention of vitamin and mineral deficiencies
– Revised every 5 year
 Dietary goals
– Goals for healthy diet
– Health promotion and disease prevention

18. DietaryGoals

19. Overnutrition
Major cause of many diseases: obesity,
diabetes, hypertension, etc.
High morbidity (disease)
and mortality

20. Nutritional Importance of ProteinsNutritional Importance of Proteins
Proteins supply amino acids and aminoProteins supply amino acids and amino
nitrogen for the synthesis of importantnitrogen for the synthesis of important
nitrogenous compounds such as purines,nitrogenous compounds such as purines,
pyrimidines and hemepyrimidines and heme
Types of amino acids:Types of amino acids:
– Essential (body can’t synthesize)Essential (body can’t synthesize)
– Non-essential (body can synthesize)Non-essential (body can synthesize)

21. RDA: 0.8 gms/kg body weight
World Health Organization
10 to 15 % of total calories
Recommended Daily Protein IntakeRecommended Daily Protein Intake

22. Recommended Daily Protein IntakeRecommended Daily Protein Intake
(mg/Kg body wt.)(mg/Kg body wt.)
 Infants (4–6 months)Infants (4–6 months)
– 11001100
 Children(10–12 year)Children(10–12 year)
– 10001000
 Adult (Men and Women)Adult (Men and Women)
– 800800
 PregnancyPregnancy
– Additional 200Additional 200
 LactationLactation
– Additional 300Additional 300

23. Essential amino acids are not synthesized byEssential amino acids are not synthesized by
the body and must be supplied in dietthe body and must be supplied in diet
PVT TIM HALLPVT TIM HALL
PPhenylalaninehenylalanine TThreoninehreonine HHistidine*istidine*
VValinealine IIsoleucinesoleucine AArginine*rginine*
TTryptophanryptophan MMethionineethionine LLysineysine
LLeucineeucine
*Essential only in children*Essential only in children
Essential Amino AcidsEssential Amino Acids

24. Normal Nitrogen BalanceNormal Nitrogen Balance
– In a healthy person, the nitrogen intake isIn a healthy person, the nitrogen intake is
equal to nitrogen lossequal to nitrogen loss
Negative nitrogen balanceNegative nitrogen balance
– When nitrogen loss is more than intakeWhen nitrogen loss is more than intake
Positive nitrogen balancePositive nitrogen balance
– When nitrogen intake is more than lossWhen nitrogen intake is more than loss
N i t r o g e n B a l a n c eN i t r o g e n B a l a n c e

25. Protein-Energy MalnutritionProtein-Energy Malnutrition
Malnutrition:Malnutrition:
– Condition/disease caused by not eatingCondition/disease caused by not eating
enough food or not eating a balanced dietenough food or not eating a balanced diet
Malnutrition due to inadequate intake ofMalnutrition due to inadequate intake of
proteins or energyproteins or energy
Two conditions:Two conditions:
– MarasmusMarasmus
– KwashiorkorKwashiorkor

26. Marasmus:Marasmus:
– Inadequate intake of both proteins andInadequate intake of both proteins and
energy (calories)energy (calories)
– Occurs in growing children under 5 yearOccurs in growing children under 5 year
– Usually found in poor populationUsually found in poor population
suffering from food shortagesuffering from food shortage

27. Clinical FeaturesClinical Features
– Thin appearanceThin appearance
– Weight lossWeight loss
– Small for his/her ageSmall for his/her age
– Poor physical/mental developmentPoor physical/mental development
– Weak immune systemWeak immune system
– Sensitive to developing infectionSensitive to developing infection

28.  KwashiorkorKwashiorkor
– Inadequate intake of proteins with adequateInadequate intake of proteins with adequate
energy intakeenergy intake
 Clinical featuresClinical features
– Edema (swelling of body)Edema (swelling of body) – Dry, weak hair– Dry, weak hair
– DiarrheaDiarrhea –– DermatitisDermatitis
– Weak immune systemWeak immune system – Retarded growth– Retarded growth
– Sensitive to developing infectionSensitive to developing infection

29. Excess Protein-Energy IntakeExcess Protein-Energy Intake
Can lead to obesity, diabetes, hypertension,Can lead to obesity, diabetes, hypertension,
coronary heart disease, etc.coronary heart disease, etc.

30. C a r b o h y d r a t e sC a r b o h y d r a t e s
Their major role in diet is energy productionTheir major role in diet is energy production
Excess carbohydrates are converted toExcess carbohydrates are converted to
glycogen (in liver) and triacylglycerols (fat) forglycogen (in liver) and triacylglycerols (fat) for
storage in adipose tissuestorage in adipose tissue
Carbohydrate intolerancesCarbohydrate intolerances
– Diabetes mellitusDiabetes mellitus
– Lactase insufficiencyLactase insufficiency

31. Carbohydrates
 Provide 4 kcals/gram
 Major energy supply to the cells
 RDA: 130 grams/day for adults and children
World Health Organization
– Lower limit: 55% of total calories
– Upper limit: 75% of total calories

32. Carbohydrates in Food
 Added
– table sugar (sucrose)
– honey, high fructose
corn syrup, fruit juice
concentrate, etc.
 Naturally occurring
– fruit (fructose)
– milk (lactose)
 Refined grains
– white breads, rice, pasta
– cereals, crackers
 Whole grains
– whole wheat breads and
pasta; brown and wild rice
– whole oats
– cereals, crackers and baked
goods made with “100%
whole wheat flour”
Simple Carbohydrates Complex Carbohydrates

33. Carbohydrates
Protein-sparing effect
Dietary protein requirement and CHO
diet are related to each other
If CHO intake is less than 130 g/day:
–more protein is metabolized
–more gluconeogenesis

34. Carbohydrates
CHO have protein-sparing effect:
–inhibit gluconeogenesis from amino
acids
–amino acids are used for repair and
maintenance of tissue protein
–not for gluconeogenesis
Protein-sparing (protein-saving)

35. Fats in the DietFats in the Diet
 Concentrated source of energy – 9 kcals/gramConcentrated source of energy – 9 kcals/gram
 Triacyglycerols (fats) are used as energy sourceTriacyglycerols (fats) are used as energy source
 Supply essential fatty acids that cannot beSupply essential fatty acids that cannot be
synthesized by the body (linoleic and linolenic acids)synthesized by the body (linoleic and linolenic acids)
 Phospholipids are essential for membrane functionPhospholipids are essential for membrane function
 Help in the absorption of fat-soluble vitaminsHelp in the absorption of fat-soluble vitamins
 Source of fat-soluble vitamins (A, D, E and K)Source of fat-soluble vitamins (A, D, E and K)

36. Fats in the diet
 Contribute to the satiety (satisfactions) of a meal
 Contribute to taste and smell of foods
 May stimulate appetite
 Slow gastric emptying
Excessive fat intake can causeExcessive fat intake can cause
– atherosclerosis/heart diseaseatherosclerosis/heart disease

37. Dietary Fat
From animals and plants
 Animal fats
– Usually high melting point
– Solid (hard) at room temperature
 Plant fats (oils)
– Usually low melting point
– Liquid at room temperature

38. Recommendations for Total Fat
World Health Organization
– Lower limit: 15% of total calories
– Upper limit: 30% of total calories
National Cancer Institute
– 30% or less of total calories

39. Recommendations for Saturated Fat
World Health Organization
–Lower Limit: 0% of total calories
–Upper Limit: 10% of total calories

40. Essential Fatty Acids
 Two essential fatty acids:
– α-linolenic acid (ω-3 fatty acid)
– linoleic acid (ω-6 fatty acid)
 Deficiency causes: scaly skin, dermatitis, reduced growth
(most common in infants)
 Deficiency very rare
 ω-3 and ω-6 fatty acids used to make eicosanoids which
appear to have cardioprotective effects
– decreased blood clotting
– decreased blood pressure

41. Food Sources of α-Linolenic Acid
 Vegetable Oils
– Soybean oil
– Flaxseed oil
 Fish oils
– Especially from fatty fish
– Provide a mixture of eicosapentaenoic acid
(EPA) and docosahexaenoic acid (DHA)

42. Omega-3 Fatty Acids
EPA and DHA primarily found in cold-water
ocean fish such as: albacore, mackerel, salmon,
sardines, tuna, whitefish
Play an important role as:
–Structural membrane lipids

43. Recommendations for Omega-3 Fatty Acid Intake
American Heart Association Guidelines
Population
 Patients without coronary
heart disease (CHD)
 Patients with CHD
 Patients who need to lower
triglycerides (fats)
Recommendation
 Fatty fish twice a week
 Include oils and foods rich in
α-linolenic acid (flaxseed,
canola and soybean oils;
flaxseed and walnuts)
---------
 1 gm of EPA+DHA per day
from fatty fish
 EPA+DHA supplements
---------
 2 to 4 grams of EPA+DHA
per day provided as capsules
under a physician’s care

44. Trans Fatty Acids
Unsaturated fatty acids, behaving more like
saturated fatty acids in the body
–increase serum LDL (but not HDL)
–risk of CVD
Not found in plants (animals only)
Formed during the hydrogenation of liquid
vegetable oils
Found in baked food: cookies, cakes, deep-
fried foods

45. D i e t a r y F i b e rD i e t a r y F i b e r
 The component of food that cannot be broken down byThe component of food that cannot be broken down by
human digestive enzymeshuman digestive enzymes
 Dietary fiber provides little energyDietary fiber provides little energy
 FunctionsFunctions
– Reduces constipationReduces constipation
– Increases bowel movementIncreases bowel movement
– Reduces exposure of gut to carcinogensReduces exposure of gut to carcinogens
– Decreases absorption of dietary fat and cholesterolDecreases absorption of dietary fat and cholesterol
– Delays gastric emptyingDelays gastric emptying
– Generates sensation of fullnessGenerates sensation of fullness

46. Two Types of Dietary Fiber
Most high fiber foods are a combination of insoluble and soluble dietary fibers
Insoluble Fiber
–tough, fibrous structures of fruits,
vegetables and grains
–indigestible food components that do not
dissolve in water
–usually passes though the body unchanged

47. Two Types of Dietary Fiber
Most high fiber foods are a combination of insoluble and soluble dietary fibers
Soluble Fiber
–indigestible food components that readily
dissolve in water
–gel-like or gummy in nature
–tend to be broken down by bacteria in the
colon

48. Recommendation for Dietary Fiber
 World Health Organization
– More than 25 grams per day
 Recommended Dietary Allowance (adults)
– Men: 38 grams per day
– Women: 25 grams per day

49. Sources of Insoluble Fiber
Cellulose: Whole-wheat flour, bran, vegetables
Hemicellulose: Bran, whole grains
Lignin: Mature vegetables, wheat, fruits and
edible seeds, such as flaxseeds and
strawberries

50. Sources of Soluble Fibers
 Gums: Oats, legumes,
guar, barley
 Pectin: Apples, citrus
fruits, strawberries,
carrots

51. Benefits of Fiber
Lowers serum LDL levels
Promotes feelings of fullness
Slows gastric emptying, long-term glucose
control in patients with diabetes mellitus
Reduces energy consumption by displacing
calorie-dense fats
Protects against colon cancer