N U T R I T I O N N U T R I T I O N MBC 142 4 Lectures Dr. Usman Ghani
Dec 21, 2015
N U T R I T I O NN U T R I T I O N N U T R I T I O NN U T R I T I O N
MBC 142 4 Lectures Dr. Usman Ghani
MBC 142 4 Lectures Dr. Usman Ghani
O V E R V I E WO V E R V I E WO V E R V I E WO V E R V I E W
Basic concepts of human nutritionBasic concepts of human nutrition Recommended daily allowances (RDA)Recommended daily allowances (RDA) Energy requirement in humansEnergy requirement in humans Macronutrients (proteins, Macronutrients (proteins,
carbohydrates, lipids, dietary fibers) carbohydrates, lipids, dietary fibers) and micronutrients (vitamins, minerals)and micronutrients (vitamins, minerals)
Nutritional diseasesNutritional diseases Diet and cancerDiet and cancer Dietetic treatment (treatment of disease Dietetic treatment (treatment of disease
by diet)by diet)
W h a t i s N u t r i t i o W h a t i s N u t r i t i o n ?n ?
W h a t i s N u t r i t i o W h a t i s N u t r i t i o n ?n ?
Utilization of foods by living organismsUtilization of foods by living organismsThe process of utilization is The process of utilization is
biochemicalbiochemicalHuman nutrition has three types:Human nutrition has three types:
– UndernutritionUndernutrition– Optimal nutritionOptimal nutrition– OvernutritionOvernutrition
N u t r i e n t s a n d D i e N u t r i e n t s a n d D i e tt
N u t r i e n t s a n d D i e N u t r i e n t s a n d D i e tt
Nutrients are the ingredients of food Nutrients are the ingredients of food needed for normal functioning of the needed for normal functioning of the body body
Nutrients provide energy for various Nutrients provide energy for various body functionsbody functions
Quality (what food items) and Quality (what food items) and quantity (how much nutrients) are quantity (how much nutrients) are important for maintaining good important for maintaining good health health
T y p e s o f N u t r i e n t T y p e s o f N u t r i e n t ss
T y p e s o f N u t r i e n t T y p e s o f N u t r i e n t ss
Two types:Two types:– MacronutrientsMacronutrients– MicronutrientsMicronutrients
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 sM 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 Nutrients needed by the body in large amounts are called amounts are called macronutrientsmacronutrients
Three types of macronutrientsThree types of macronutrients– ProteinsProteins– CarbohydratesCarbohydrates– FatsFats
Macronutrients provide energy and Macronutrients provide energy and building blocks of proteins, building blocks of proteins, carbohydrates and fatscarbohydrates and fats
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 sM 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 small Nutrients needed by the body in small amounts are called amounts are called micronutrientsmicronutrients
Major types of micronutrientsMajor types of micronutrients– VitaminsVitamins– Minerals / trace elementsMinerals / trace elements
Required for maintaining normal Required for maintaining normal health and preventing various health and preventing various diseasesdiseases
N u t r i e n t s f r o m D i N u t r i e n t s f r o m D i e te t
N u t r i e n t s f r o m D i N u t r i e n t s f r o m D i e te t
Proteins, carbohydrates, fatsProteins, carbohydrates, fats Essential fatty acidsEssential fatty acids Essential amino acidsEssential amino acids Vitamins Vitamins MineralsMinerals Dietary fibersDietary fibers WaterWater
Recommended Daily Recommended Daily Allowances (RDA)Allowances (RDA)
Recommended Daily Recommended Daily Allowances (RDA)Allowances (RDA)
RDA are the levels of intake of RDA are the levels of intake of essential nutrients considered by essential nutrients considered by the Food and Nutrition Board, USA, the Food and Nutrition Board, USA, to be enough to meet the nutritional to be enough to meet the nutritional needs of all healthy personsneeds of all healthy persons
RDA varies according to age and sexRDA varies according to age and sex
E n e r g y C o n t e n t o f E n e r g y C o n t e n t o f F o o d F o o d
E n e r g y C o n t e n t o f E n e r g y C o n t e n t o f F o o d F o o d
Much of the food we eat is Much of the food we eat is converted to ATP and other high-converted to ATP and other high-energy compoundsenergy compounds
This energy is used for biosynthetic This energy is used for biosynthetic pathways, muscle contraction, pathways, muscle contraction, nerve impulse, etc.nerve impulse, etc.
Energy content of food is measured Energy content of food is measured in in calories (Kilocalories)calories (Kilocalories) of heat of heat energy released by combustion energy released by combustion (burning) of that food(burning) of that food
One calorie is the heat required One calorie is the heat required to raise the temperature of 1 gm. to raise the temperature of 1 gm. of water by 1of water by 1ooCC
ProteinsProteins 4 kcal/gm 4 kcal/gmCarbohydratesCarbohydrates 4 kcal/gm 4 kcal/gmFatFat 9 kcal/gm 9 kcal/gm
E n e r g y E x p e n d i t u E n e r g y E x p e n d i t u rere
E n e r g y E x p e n d i t u E n e r g y E x p e n d i t u rere
Depends on four factors:Depends on four factors:– Surface area of the body (height and Surface area of the body (height and
weight)weight) The greater the surface area the The greater the surface area the
greater the heat lossgreater the heat loss– AgeAge
Growth and lean muscle massGrowth and lean muscle mass Infants have higher basal metabolic Infants have higher basal metabolic
rate (rate of energy utilization in rate (rate of energy utilization in resting state)resting state)
– SexSexWomen have lower BMR than Women have lower BMR than menmen
– Activity levelActivity levelExercise increases energy Exercise increases energy expenditureexpenditure
Recommended Energy IntakeRecommended Energy IntakeRecommended 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
Some DefinitionsSome Definitions
Omnivorous: Omnivorous: eat both eat both meat and vegetablesmeat and vegetables
Carnivorous: Carnivorous: eat meat eat meat onlyonly
Herbivorous: Herbivorous: eat eat vegetable, grass onlyvegetable, grass only
Vegetarianism - DefinitionsVegetarianism - Definitions
Lacto-Ovo Lacto-Ovo VegetarianVegetarian
Lacto VegetarianLacto VegetarianVeganVegan
Vegetarianism - DefinitionsVegetarianism - 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
Vegetarian and nutrient intake
Vegetarian and nutrient intake
Lower intake of iron Lower intake of calcium and
vitamin D May develop megaloblastic anemia
because of vitamin B12 deficiencyMost consume enough protein Lower in total dietary fat
Vegetarian diet and disease
(Research results)
Vegetarian diet and disease
(Research results)
Lower Body Mass Index (BMI)Ischemic heart disease lower than non-
vegetarians Lower blood pressureLower cancer rates compared to non-
vegetarians
Dietary guidelines – more about RDA
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
Food PyramidUnited States Department of Agriculture
Center for Nutrition Policy and Promotion
Food PyramidUnited States Department of Agriculture
Center for Nutrition Policy and Promotion
Educational tool for public – established in 1992
Healthy eating guide Size of each section reflects daily
servings recommended Pyramid shape Fats, oils and sweets occupy only a
tiny triangle at the top
Th
e F
ood
Pyr
am
id
Die
tary
Goals
OvernutritionOvernutrition
Major cause of many diseases: obesity, diabetes, hypertension, etc.
High morbidity (disease)and mortality
Nutritional Screening/Assessment
Nutritional Screening/Assessment
It is a nutrition assessment processIdentifies persons who are
malnourishedDone by a physician, nurse, dietitian or
other qualified health-care professional
Identifies individuals who require aggressive nutrition support
Restores or maintains an individual’s nutrition status
Identifies appropriate medical nutrition therapies
Monitors the efficacy of these interventions
Nutritional Importance of Nutritional Importance of ProteinsProteins
Nutritional Importance of Nutritional Importance of ProteinsProteins
Proteins supply amino acids and Proteins supply amino acids and amino nitrogen for the synthesis of amino nitrogen for the synthesis of important nitrogenous compounds important nitrogenous compounds such as purines, pyrimidines and such as purines, pyrimidines and hemeheme
Types of amino acids:Types of amino acids:– Essential (body can’t synthesize)Essential (body can’t synthesize)– Non-essential (body can Non-essential (body can
synthesize)synthesize)
RDA: 0.8 gms/kg body weightWorld Health Organization
10 to 15 % of total calories
Recommended Daily Recommended Daily Protein IntakeProtein Intake
Recommended Daily Recommended Daily Protein IntakeProtein Intake
Recommended Daily Protein Recommended Daily Protein IntakeIntake
(mg/Kg body wt.)(mg/Kg body wt.)
Recommended Daily Protein Recommended Daily Protein IntakeIntake
(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
Essential amino acids are not Essential amino acids are not synthesized by the body and must be synthesized by the body and must be supplied in dietsupplied in diet
PVT TIM HALLPVT TIM HALLPPhenylalaninehenylalanine TThreoninehreonine HHistidine*istidine*VValinealine IIsoleucinesoleucineAArginine*rginine*
TTryptophanryptophan MMethionineethionine LLysineysineLLeucineeucine
*Essential only in children*Essential only in children
Essential Amino AcidsEssential Amino AcidsEssential Amino AcidsEssential Amino Acids
Normal Nitrogen BalanceNormal Nitrogen Balance– In a healthy person, the nitrogen In a healthy person, the nitrogen
intake is equal to nitrogen lossintake is equal to nitrogen lossNegative nitrogen balanceNegative nitrogen balance
– When nitrogen loss is more than When nitrogen loss is more than intakeintake
Positive nitrogen balancePositive nitrogen balance– When nitrogen intake is more than When nitrogen intake is more than
lossloss
N i t r o g e n B a l a n N i t r o g e n B a l a n c ec e
N i t r o g e n B a l a n N i t r o g e n B a l a n c ec e
Protein-Energy Protein-Energy MalnutritionMalnutrition
Protein-Energy Protein-Energy MalnutritionMalnutrition
Malnutrition:Malnutrition:– Condition/disease caused by Condition/disease caused by
not eating enough food or not not eating enough food or not eating a balanced dieteating a balanced diet
Malnutrition due to inadequate Malnutrition due to inadequate intake of proteins or energyintake of proteins or energy
Two conditions:Two conditions:– MarasmusMarasmus– KwashiorkorKwashiorkor
Marasmus:Marasmus:– Inadequate intake of both Inadequate intake of both
proteins and energy (calories)proteins and energy (calories)– Occurs in growing children Occurs in growing children
under 5 yearunder 5 year– Usually found in poor Usually found in poor
population suffering from food population suffering from food shortageshortage
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
KwashiorkorKwashiorkor– Inadequate intake of proteins with Inadequate intake of proteins with
adequate energy intakeadequate energy intake Clinical featuresClinical features
– Edema (swelling of body)Edema (swelling of body) – Dry, weak – Dry, weak hairhair
– DiarrheaDiarrhea –– Dermatitis Dermatitis– Weak immune systemWeak immune system – Retarded – Retarded
growthgrowth– Sensitive to developing infectionSensitive to developing infection
Excess Protein-Energy Excess Protein-Energy IntakeIntake
Excess Protein-Energy Excess Protein-Energy IntakeIntake
Can lead to obesity, diabetes, Can lead to obesity, diabetes, hypertension, coronary heart hypertension, coronary heart disease, etc.disease, etc.
C a r b o h y d r a t e sC a r b o h y d r a t e sC 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 Their major role in diet is energy productionproduction
Excess carbohydrates are converted Excess carbohydrates are converted to glycogen (in liver) and to glycogen (in liver) and triacylglycerols (fat) for storage in triacylglycerols (fat) for storage in adipose tissueadipose tissue
Carbohydrate intolerancesCarbohydrate intolerances– Diabetes mellitusDiabetes mellitus– Lactase insufficiencyLactase insufficiency
CarbohydratesCarbohydrates
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
Carbohydrates in FoodCarbohydrates 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
CarbohydratesCarbohydratesProtein-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
CarbohydratesCarbohydratesCHO 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)
Fats in the DietFats in the DietFats 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 Triacyglycerols (fats) are used as energy
sourcesource Supply essential fatty acids that cannot be Supply essential fatty acids that cannot be
synthesized by the body (linoleic and linolenic synthesized by the body (linoleic and linolenic acids)acids)
Phospholipids are essential for membrane Phospholipids are essential for membrane functionfunction
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)
Fats in the dietFats in the diet
Contribute to the satiety (satisfactions) of a meal
Contribute to taste and smell of foodsMay stimulate appetiteSlow gastric emptyingExcessiveExcessive fat intake fat intake can causecan cause
– atherosclerosisatherosclerosis/heart disease/heart disease
Dietary FatFrom animals and plantsDietary 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
Recommendations for Total Fat
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
Recommendations for Saturated Fat
Recommendations for Saturated Fat
World Health Organization–Lower Limit: 0% of total calories
–Upper Limit: 10% of total calories
Essential Fatty AcidsEssential 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
Essential Fatty AcidsEssential Fatty Acids
Food Sources of α-Linolenic Acid
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)
Omega-3 Fatty AcidsOmega-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–Modulator of ω-6 fatty acid metabolism
Recommendations for Omega-3 Fatty Acid Intake
American Heart Association Guidelines
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 -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
Mediterranean DietMediterranean Diet Seasonal food More vegetables and fruits Less red meats Olive oil – a major fat source Rich in:
– monounsaturated fatty acids (olive oil)– Omega-3 fatty acids (fish, nuts)
Low in saturated fat Reduces total serum cholesterol and LDL
Trans Fatty AcidsTrans 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 oilsFound in baked food: cookies, cakes,
deep-fried foods
D i e t a r y F i b e rD i e t a r y F i b e rD 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 The component of food that cannot be broken down by human digestive enzymesbroken down by human 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 Decreases absorption of dietary fat and
cholesterolcholesterol– Delays gastric emptyingDelays gastric emptying– Generates sensation of fullnessGenerates sensation of fullness
Two Types of Dietary FiberMost high fiber foods are a combination of insoluble and soluble
dietary fibers
Two Types of Dietary FiberMost 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
Two Types of Dietary FiberMost high fiber foods are a combination of insoluble and soluble
dietary fibers
Two Types of Dietary FiberMost 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
Recommendation for Dietary Fiber
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
Sources of Insoluble FiberSources of Insoluble Fiber
Cellulose: Whole-wheat flour, bran, vegetables
Hemicellulose: Bran, whole grainsLignin: Mature vegetables, wheat,
fruits and edible seeds, such as flaxseeds and strawberries
Sources of Soluble FibersSources of Soluble Fibers
Gums: Oats, legumes, guar, barley
Pectin: Apples, citrus fruits, strawberries, carrots
Benefits of FiberBenefits of Fiber
Lowers serum LDL levelsPromotes feelings of fullnessSlows gastric emptying, long-term
glucose control in patients with diabetes mellitus
Reduces energy consumption by displacing calorie-dense fats
Protects against colon cancer
Nutrition and cancerNutrition and cancer
Nutritional problems in cancer Cachexia
– Weakness, loss of appetite, metabolic/hormonal abnormalities, weight loss
Change in taste, lack of energy, feeling of fullness, nausea, vomiting
Tumors produce substances that cause loss of appetite
Nutritional problems due to cancer treatment Radiation therapy:
– Causes dry mouth, gum destruction, change in taste, difficulty in swallowing, malabsorption of nutrients, GIT damage
Chemotherapy:– Severe side effects
Surgery:– Limited swallowing/digestion of food– Limited absorption of nutrients
Nutritional needs of cancer patients– The diet must supply all nutrients– Energy and protein needs are increased by
20%– 3000 to 4000 calories– 100 to 200 g of proteins in the diet:
To prevent tissue breakdown/weight loss
Dietetic Treatment (Diet Therapy)
Dietetic Treatment (Diet Therapy)
Treatment or control of diseases by therapeutic diet (modified diet)
Purpose:– Maintain/improve nutritional status– Maintain, increase or decrease body
weight– Rest certain organs or whole body– Adjust the diet so that the body can handle
it in a disease
How diet is modified?How diet is modified?
Basic diet becomes therapeutic when:– Calories, fiber, some nutrients, food
types are increased or decreased– Diet is modified to become soft or liquid– Certain foods are eliminated
Some examples of therapeutic dietsSome examples of therapeutic diets
Consistency– Mechanical, tube feeding, high fiber,
liquidCarbohydrates
– Diabetic diet, Low-calorie diet– Ketogenic diet– Lactose-free diet
Some examples of therapeutic dietsSome examples of therapeutic diets
Fat– Restricted fat diet– Low cholesterol diet
Proteins– Restricted protein diet– Gluten-free diet– Restricted phenylalanine diet (for PKU)– Restricted purine diet (for gout)– High protein diet
Diet therapy of diabetes mellitus
Diet therapy of diabetes mellitus
Calories– Calorie intake should be the same for
diabetics compared to non-diabetics– Adjustment in calories by modifying food
contentsProteins
– 15 to 20% calories from proteins– RDA: 1 to 1.5 gm/kg
Carbohydrates– CHO content is the same as for normal diet– More complex CHOs + high fiber– Use of nutritive / non-nutritive sweeteners
Fats– 20 to 30% calories from fat– Low fat, lean meats, polyunsaturated fats,
low cholesterol
Complex CHOs and fiber:– Improve glycemic control in diabetics– Lower serum cholesterol, triglycerides– Promote weight loss
50 g or more fiberUpto 60% complex CHO intake
Diet therapy of renal diseases
Diet therapy of renal diseases
Calories– Protein restricted diet– Adequate calories are provided in the
diet from other sources (fats, CHO) to avoid protein degradation in muscle
Proteins– RDA for renal patients: 0.5 to 1.5 gm/kg– Normal amount of proteins is provided if
kidney function is normal– Restricted protein diet for patients with
reduced kidney function to avoid retention of protein met. products
– Protein content is increased to compensate for high albumin loss in urine
Electrolytes– Restricted sodium (500 mg/day) to avoid
edema in hypertensive patients– Restricted potassium (1.5 gm/day)
Retained in kidney failure patients
Fluids– Restricted in patients with kidney failure– A balance of urinary input and output is
maintained
Diet therapy of hyperlipidemia and
cardiovascular disease
Diet therapy of hyperlipidemia and
cardiovascular disease
Saturated fat, cholesterol restricted dietMore polyunsaturated fatsDiet should meet RDA for proteins, CHOsSodium restricted diet to prevent:
– Hypertension– Congestive heart failure
Sodium intake: 250 to 2000 mg/day