1. The Foundations of Human Nutrition
Course #: 550101
Lecture 1
Healthy diet and Body compositions
Haneen S. Dwaib BSc, MPH, PhD
2. Overview…
• If you live for 65 years or longer, you will have consumed more than
70,000 meals, and your remarkable body will have disposed of 50
tons of food. The foods you choose most often have cumulative
effects on your body.1* As you age, you will see and feel those
effects—if you know what to look for.
3. Important concepts…
• Diet: the foods (including beverages) a person usually eats and drinks.
• Food: medically, any substance that the body can take in and
assimilate that will enable it to stay alive and to grow; the carrier of
nourishment; socially, a more limited number of such substances
defined as acceptable by each culture.
• Nutrients: components of food that are indispensable to the body’s
functioning. They provide energy, serve as building material, help
maintain or repair body parts, and support growth.
4. What is Nutrition?
the study of the nutrients in foods and in the body;
sometimes also the study of human behaviors related
to food.
5. • Calories: units of energy. In nutrition
science, the unit used to measure the energy
in foods is a kilocalorie (also called kcalorie or
Calorie): it is the amount of heat energy
necessary to raise the temperature of a
kilogram (a liter) of water 1 degree Celsius.
• Essential nutrients: the nutrients the body
cannot make for itself (or cannot make fast
enough) from other raw materials; nutrients
that must be obtained from food to prevent
deficiencies.
8. • NUTRIENT DENSITY
▪ Nutritional quality of a food
▪ Comparing vit & min content in food to amount of calories it provides
• ENERGY DENSITY
▪ Very low (less than 0.6kcal/gram)
▪ Low (.6 to 1.5kcal/g)
▪ Medium, High (greater than 4kcal/g)
8
FOOD PHILOSOPHY
10. What is empty calories?
• calories provided by added sugars and solid fats with few or no other
nutrients. Other empty calorie sources include alcohol, and highly
refined starches, such as corn starch or potato starch, often found in
ultra-processed foods.
21. Healthy Habits to Adopt
• Consume a healthy diet
• Control your weight
• Drink alcohol in moderation (optional)
• Exercise > 30 minute a day
• Don’t smoke
22. Recommendations for food choice
Menu planning tools
• MyPyramid
(former food guide pyramid)
MyPyramid.gov
• Myplate.gov- newest tool
• Dietary Guidelines for Americans
(special guidelines also available for Lebanon and the region)
22
25. • Choose low-fat/fat free options
• Include plant proteins several times a week
• Include dark green vegetable every day
• Include vitamin C-rich food every day
• Choose whole-grain products
• Include plant oils daily
• Eat fish at least twice a week
Using MyPlate
27. 27
What counts as a serving
• Bread, cereal, rice and pasta:
1 slice of bread,1/4 loaf Arabic bread(30g)
½ cup of cooked rice, pasta, bulgur..
½ cup of breakfast cereals
• Milk and dairies:
1 cup of milk or yogurt
45g of cheese
40g of labneh
28. 28
What counts as a serving
• Fruits
1 medium apple, orange, banana(1 cup)
½ of cooked fruits
¼ cup of dried fruits
½ of cup of fruit juice
• Vegetables
2 cups of leafy vegetables
1 cup of other raw vegetables
½ cup of other cooked vegetables
29. 29
• Meat, poultry, fish, beans, eggs and nuts:
30g of cooked meat, poultry or fish
½ cup of cooked beans
1 egg
1/3 cup of nuts
• Fats and oils:
1 teaspoon of oil, butter, ghee, mayo..
What counts as a serving
30. 30
Discretionary calories
• Calories allowed in a diet after meeting nutritional needs
• Generally small amount of calories
(130-260kcals)
• Give flexibility to add some foods and beverages that may
contain: added fat, added sugar, alcohol
35. Dietary Reference Intake (DRI)
• Ongoing and collaborative effort
• Health Canada and the Food and Nutrition Board of the
Institute of Medicine (US)
39. Lecture 2:
Introduction to the
Gastrointestinal tract (GI)
Haneen S. Dwaib
BSc, MPH, PhD
Haneen.dwaib@paluniv.edu.ps
The Foundations of Human Nutrition
Course #: 550101
41. The Esophagus
• Long tube
• Epiglottis
• Peristalsis
• Lower esophageal sphincter
• Heartburn
42. The Stomach
• Sphincters
• Size
• Gastric juices (Acid)
• Holding “tank”
• Formation of chyme
• Prevention of auto digestion
43. Stomach Acid
• Destroys activity of protein
• Activates digestive enzymes
• Partially digests dietary protein
• Assists in calcium absorption
• Makes dietary minerals soluble for absorption
44. The Small Intestine
• Approximately approximately 3,5 meters
• Folded walls
• Villi
• Absorptive cells
• Rapid cell turnover
45. The Large Intestine
• Indigestible food stuff
• No villi or enzymes
• Absorption of water, some minerals, vitamins
• Presence of beneficial Bacteria
• Elimination
47. 47
The flow of Food
ORGAN Time food stays there
Mouth Minutes or less
Throat Seconds
Esophagus 1 to 6 sec. for liquids; 30 to 60
sec. for solids
Stomach 4 Hrs.
Small Intestine 6 Hrs.
Large Intestine 14-72 Hrs.
48. • Control valves: Sphincters
-in the lower esophagus
-at the base of the stomach
-at the end of the small intestine
-at the end of the large intestine
• Special type of movement:
-peristalsis
48
The flow of Food
53. The Pancreas
• Digestive enzymes
• Hormones
- Glucagon and insulin
• Pancreatic juices
- Bicarbonate
54. 54
Absorption
• Stomach: alcohol, water
• Small intestine: vitamins, minerals and all other nutrients
• Large intestine: sodium, potassium and Water
69. Glucose Fructose (fruit sugar) Galactose
Major monosaccharide in the
body
In sucrose In lactose
Also known as dextrose In fruit, honey, and high-
fructose corn syrup
Converted to glucose in the
liver
In bloodstream called blood
sugar
Converted into glucose in the
liver
Breakdown of starches and
sucrose
Source of fuel for cells
Monosaccharide
70. Sucrose Lactose Maltose
Major sugar in fruits and
vegetables
In Milk In Cereals and grains
Made from glucose + fructose Made from glucose +galactose Made from 2 glucose units.
Disaccharides
72. Starch Glycogen Dietary Fiber
Amylose
Storage form of
carbohydrates in plants
Storage form of carbohydrate
for animals and human
Undigested starch
Amylopectin
Storage form of
carbohydrates in plants
Found in the liver and
muscles
Body cannot break the
bonds
Polysaccharides
3,000 or more monosaccharides
73. • Insoluble or Non-fermentable fiber
- Cellulose, hemicellulose, lignin
- Not fermented by the bacteria in the colon
• Soluble or Viscous fiber
- Gum, pectin, mucilage
- Fruit, vegetable, rice bran, psyllium seed
Dietary Fiber
74. Functional Fiber
• Fiber added to food
- Provides health benefits
• Prebiotics – Type of functional fiber
- Stimulate growth or activity of beneficial bacteria in the
large intestine
80. Digestion of Carbohydrate
• Salivary amylase
- Breaks starch to shorter saccharides
- Prolonged chewing
• Short duration in the mouth
In the Mouth
81. • Acidic environment
• No further starch digestion
In the stomach
Digestion of Carbohydrate
82. • Pancreas releases enzymes
- Pancreatic amylase
• Absorptive cells release
- Maltase
- Sucrase
- Lactase
• Monosaccharides are absorbed
Digestion of Carbohydrate
In the Small intestine
83. • Only a minor amount escapes digestion
• Travels to the colon
• Fermentation by the bacteria
• Acids and gases produced are absorbed
• May promote health of the colon
Undigested Carbohydrates
84. • Reduction in lactase
- Lactose is undigested and not absorbed
- Lactose is metabolized by large intestinal bacteria
• Causes gas, bloating, cramping, discomfort
• Primary lactose maldigestion
• Secondary lactose maldigestion
• Severe cases are called lactose intolerance
Lactose Maldigestion
85. • Determine amount you can tolerate
• Eat dairy with fat (some tolerate better fat free
products)
• Cheese & yogurt are usually well tolerated
• Use Lactase Tablets (supplements)
What To Do if You Have Lactose
Maldigestion or Lactose Intolerance?
90. • Role of the liver
- Regulates glucose that enters bloodstream
• Role of the pancreas
- Release of insulin
- Release of glucagon
Blood Glucose Control
91. • Promotes glycogen synthesis
• Increases glucose uptake by the cells
• Reduces gluconeogenesis
• Net effect : lowers blood glucose
Functions of Insulin
92. Functions of Glucagon
• Breakdown glycogen
• Enhances gluconeogenesis
• Net effect: raises blood glucose
94. Glycemic Response
• Glycemic Index
- Ratio of blood glucose response to a given food
• Glycemic Load
- Grams of carbohydrate in a food multiplied by the
glycemic index of that food
- Divide result by 100
95. High Glycemic Load
• Large release of insulin
• Increase blood triglycerides level
• Increase Low Density Lipoprotein (LDL)
• Increase fat deposits
• Increase clotting
• Increase fat synthesis
• Rapid return of hunger
• Insulin resistance develops (Type 2 diabetes)
99. Health benefits of fibres
• Prevention & treatment of constipation
• Prevention of colon cancer
• Decreases blood cholesterol
• Helps regulate blood sugar (Diabetes)
• Helps in weight control by increasing satiety
Recommended intake: 20-35g / day
100. Cholesterol and (Soluble) Fiber
• Absorption of cholesterol inhibited
• Bile acid absorption reduced
• Risk for cardiovascular disease and gallstones reduced
• Insulin release decreased
- Decrease cholesterol synthesis in the liver
• Blood cholesterol lowered
104. Weight Control and Fiber
• Filling
• Low in kcal
• Satisfied after eating
105. Carbohydrate Needs
• RDA is 130 grams/day for adults
• Average U.S. intake is 180-330 grams
• Recommendations vary
45%- 65% of total calories
Focus on fruits, vegetables, whole grains
106. Recommended Dietary Fiber Intake
• AI is 25 grams/day for women
• AI is 38 grams/day for men
• (Goal of 14 grams/1000 kcal)
• DV is set at 25 grams for 2000 kcal diet
• Average U.S. intake:
Women Men
14 grams/ day 17 grams/ day
107. Too Much Fiber
• > 60 grams/day
• Extra fluid needed
• May decrease availability of some minerals
• Unmet energy needs in children
108. Recommendation for Simple Sugar Intake
• Low nutrient density
• Dental caries
• Added to food and beverages
• < 10% of total kcal/day with a maximum of 50 grams (12
tsp) per day—WHO
• Average U.S. intake: 16% of total kcal/day
~82 grams per day
109. SUGAR
• 1 teaspoon = 20 kcal
= 4 grams of CHO
• Recommendation: 10% of total calorie intake
Example : 2000kcal diet = 200kcal = 13 tsp.
110. • Brown sugar
• Turbinado sugar (raw sugar)
• Maple syrup
• Honey
SUGAR
111. High-fructose Corn Syrup
• 55% fructose
• Cornstarch mixed with acid and enzymes
• Starch is broken down to glucose
• Some glucose is converted to fructose
• Cheaper than sucrose
• Does not form crystals
112. Sugar in processed foods
• 1 Cup cola: 7 tsp sugar
• 1 tbsp ketchup: 1tsp sugar
• 1 cup sweetened yogurt: 7 tsp sugar
• 30 g chocolate: 4 tsp sugar
115. Sugar Alcohols
• Sorbitol, Xylitol, Maltitol
• ~2.6 kcals/gram
• Large quantities can cause diarrhea
• Do not promote tooth decay
• Used in gum candies
• Absorbed and metabolized slower
117. Aspartame (Equal, NutraSweet)
• Composed of phenylalanine, aspartic acid, and methanol
• 180-200x sweeter than sucrose
• 4 kcal/gm
• Not heat stable
• Complaints of sensitivity
- Headaches, dizziness, seizures, nausea, etc.
• Acceptable daily intake: 50 mg per kg body weight
(FDA) (~14 cans of diet soda for average adult per day)
• Warning label for Phenylketonuria (PKU)
118. Sucralose (Splenda)
• 600x sweeter than sucrose
• Substitutes chlorines for hydroxyl groups on sucrose
• Heat stable
• Tiny amount digested
• Excreted in the feces
119. Neotame
• FDA approved for general-purpose sweetener
• Similar structure to Aspartame
• Is not broken down in the body
• 7,000-13,000x sweeter than sucrose
• Heat stable
• Safe for use
120. Acesulfame-K (Sunette)
• Approved by FAD
• 200x sweeter than sucrose
• Not digested by the body
• Heat stable
• Diabetisweet used in baking
121. Tagatose
• Altered form of Galactose
• Almost same sweetness as sucrose
• 1.5 kcals/gram
• Does not increase glucose levels
• Does not cause tooth decay
• Is fermented by the large intestine
122. Stevia (Sweet Leaf®)
• 100-300X sweeter than sucrose
• Provides no energy
• Generally recognized as safe (GRAS)
123. The Foundations of Human
Nutrition
Course #: 550101
Lecture 4
Lipids
Haneen S. Dwaib BSc, MPH, PhD
124. Lipids
• Do not readily dissolve in water
• Types of lipids:
- Triglycerides
- Phospholipids
- Sterols (Cholesterol)
• Fats (solid) and oils (liquid)
- 9 kcal /gm
125. Fatty Acids
• Found in our body and foods
- In triglycerides
• Saturated fatty acids
- Solid form
• Unsaturated fatty acids
- Liquid form
- Cis and Trans
• Fats are composed of both saturated and unsaturated
126. Saturated Fatty Acid Structure
omega end alpha end
H H H H H H H H H H H H H H H H H O
H-C--C--C--C--C--C--C--C--C--C--C--C--C--C--C--C--C-C-OH
H H H H H H H H H H H H H H H H H
Degree of saturation: single carbon bond
127. Monounsaturated Fatty Acid
Structure
omega end alpha end
H H H H H H H H H H H H H H H O
H-C--C--C--C--C--C--C--C--C=C--C--C--C--C--C--C--C--C-OH
H H H H H H H H H H H H H H H H H
One double bond
128. Polyunsaturated Fatty Acid
Structure
omega end alpha end
H H H H H H H H H H H H H O
H-C--C--C--C--C--C=C--C--C=C--C--C--C--C--C--C--C--C-OH
H H H H H H H H H H H H H H H H H
>2 double bond
131. Essential Fatty Acids
• Omega-3 fatty acid (alpha-linolenic acid)
• Omega-6 fatty acid (linoleic acid)
• Body can only make double bonds after the 9th carbon
from the omega end
• Functions
- Immune function
- Vision
- Cell membrane, and production of hormone-like
compounds
134. Phospholipids
• Built on a glycerol
backbone
• Contains phosphorus
compound(s)
• Found in body
• Synthesized by the body
as needed
135. Functions of Phospholipids
• Component of cell membrane
• Emulsifier
- Bile acids
- Lecithins
- Improves food products
• Found in wheat germ, peanuts, yolks, soy beans,
organ meat
136. Sterols
• Multi-ringed structure
• Do not have a glycerol backbone
• Cholesterol is a sterol
• Waxy substance
• Do not readily dissolve in water
• Found in animal foods
137. Functions of Cholesterol
• Essential component of cell membrane
• Produced by the liver
• Found only in animal products
• Forms important hormones
- Estrogen, testosterone, vitamin D
• Precursor to bile acids
140. Hydrogenation of Fatty Acids
• Process used to solidify an oil
• Addition of H to C=C double bonds
• Increases shelf life
• Formation of trans fatty acid
(similar to shape of saturated fatty acid)
143. Excessive Trans Fatty Acid Intake
• Raises LDL
• Lowers HDL
• Increases risk for cardiovascular disease
• Current intake is 3%-4% of total kcal
• Added to food labels Jan. ‘06
144. Minimize Intake of Trans Fat
• Limit use of hydrogenated fats
• Limit deep-fried foods
• Limit high-fat baked goods
• Limit use of non-dairy creamers
147. Digestion of Fat in the Stomach
Gastric lipase
- Activated by an acidic environment
- Acts on triglycerides containing short- and
medium-chain fatty acids
148. Digestion of Fat in the Small Intestine
• Primary site of fat digestion
- pancreatic lipase
• Bile acid released
- Emulsifies digested fat
• Fat is broken down
- To monoglycerides and fatty acids
151. Absorption of Fat
• 95% of dietary fat is absorbed
• Diffused into the absorptive cells
• Short- and medium-chain fatty acids
• Long-chain fatty acids re-form into triglycerides
154. Transportation of Synthesized Fat
• Made primarily by the liver
• Very-Low-Density Lipoprotein (VLDL)
• Low-Density Lipoprotein (LDL)
• High-Density Lipoprotein (HDL)
155. Carrying lipids in the blood
• Chylomicrons: carry dietary fat to the cells
• VLDL: carries lipids from the liver
• LDL: carries cholesterol from the liver to the cells.
• HDL: carries cholesterol from the cells and excretes
it from the body
157. High-Density Lipoprotein
(HDL)
• Synthesized by liver and intestine
• High proportion of protein
• Picks up cholesterol from dying cells and other sources
• Transfers cholesterol to other lipoproteins
• Transfers cholesterol directly back to the liver
158. Benefits of (a high) HDL (level)
• Removes cholesterol from the bloodstream
• HDL may block oxidation of LDL
• Reduces risk of cardiovascular disease
• Pre-menopausal women have higher HDL
160. Essential Fatty Acid- Omega-3
(alpha-linolenic acid)
omega end alpha end
H H H H H H H H H H H H H H H H H O
H-C--C--C=C--C--C =C--C--C=C--C--C--C--C--C--C--C--C-OH
H H H H H H H H H H H
1st double bond is located on the 3rd
carbon from the omega end
161. Omega-3 Fatty Acid
• Primarily from fish oil
• Also found in canola, walnuts, flax seeds,
mussels, crab, shrimp, and soybean oil
• Recommended intake of ~2 servings of fish per
week
162. H H H H H H H H H H H H H O
H-C--C--C--C-- C--C =C--C--C=C--C--C--C--C--C--C--C--C-OH
H H H H H H H H H H H H H H H H H
omega end alpha end
Essential Fatty Acid- Omega-6
(alpha-linoleic acid)
First double bond is located on the 6th
carbon from omega end
163. Omega-6 Fatty Acid
• Found in vegetable oils
• Only need
~ 2-4 tablespoons a day
166. Functions of Fatty Acids
• Provide energy
• Efficient storage of energy
• Insulation
• Protection
• Transport fat-soluble vitamins
• Some satiety
• Flavor and mouth feel
167. Recommendations for Fat Intake
• No RDA
• AHA recommendations
- 20-30% of total kcal from fat
- 7-10% can come from saturated/trans fat
- 200-300 mg cholesterol/day
Keep saturated fat, cholesterol, and trans fat to a minimum
• Average U.S. intake:
- 33% of total kcal from fat
- 13% of kcal from saturated fat
- 180-320 mg cholesterol/day
170. Other Recommendations
• Fat intake can be higher as long as saturated and trans
fatty acid are minimal
• Eat plenty of fruits and vegetables
• Cut down on red meats
• Cut down on simple sugars and refined carbohydrate
• Promote healthy weight
• Be active
173. Risk Factors
• Total blood cholesterol > 200 mg/dl
• Smoking
- Increases clotting
- Increases expression of genetic link
• Hypertension (> 139/89)
• Diabetes
- Insulin increases cholesterol synthesis
- Guarantees development of cardiovascular disease
174. Other Risk Factors
• Low HDL (< 40 mg/dl)
• Age
• Family history
• Blood triglycerides > 200 mg/dl
• Obesity
- Fat around the waist
- Insulin resistance
• Inactivity
175. Lowering LDL
• See your doctor to assess for other conditions
• Reduce dietary saturated fat and cholesterol
• Increase Mono-Unsaturated FA and Poly-
Unsaturated FA
• Increase dietary fiber (soluble)
176. • Is the most diet-responsive blood lipid
• Avoid overeating
• Limit alcohol
• Limit simple sugars
• Small frequent meals
• Include fish in the diet
Lowering Blood TG
177. Raising HDL
• Physical activity
• At least 45 min/day, 4 days a week
• Don’t smoke
• Eat regularly
• Eat less total fat
• Red wine consumption (controversy)
178. Hidden Fat
• Look on the Nutrition Facts labels
• Look on the lists of ingredients
• Control portion size
180. Fat Substitutes
• Water
Diet margarine
• Z-trim
Starch derivative that binds with
water
• Fiber cellulose
Maltrin, Stellar, Oatrim
• Dairy-Lo
Protein globules
• Olestra or Olean (links fatty acid to
sucrose)
Not digested
FDA approved for fried snack foods
Fat-soluble vitamins issue
• Salatrim or Benefat
Fat and sucrose
Not digested and/or absorbed well
181. Rancidity
• Decomposed oils
• Breakdown of the C=C bonds by UV light, and/or O2
• Unpleasant odor and flavor
• PUFA more susceptible
• Limited shelf life
182. Prevention of Rancidity
• Hydrogenation
• Addition of vitamin E
• Addition of additives such as: Butylated
hydroxyanisol (BHA) and Butylated hydroxytolune
(BHT)
183. The Foundations of Human
Nutrition
Course #: 550101
Lecture 5
Proteins
Haneen S. Dwaib BSc, MPH, PhD
Haneen.dwaib@paluniv.edu.ps
184. Overview of Protein
• Body is made up of thousands of proteins
• Contains nitrogen, carbon, hydrogen, and oxygen
• Functions:
- Regulates and maintains body functions
- Provides essential form of nitrogen
(in the form of amino acids)
186. Protein Organization
• Order of amino acids in a protein determines its
ultimate shape
• Protein’s final shape determines its function in the
body
187. Important concepts
• Conditionally essential AA: amino acid that is normally
nonessential but must be supplied by the diet in special
circum- stances when the need for it exceeds the body’s
ability to produce it.
• peptide bond a bond that connects one amino acid with
another, forming a link in a protein chain.
• polypeptide (POL-ee-PEP-tide) protein fragments of many
(more than 10) amino acids bonded together (poly means
“many”). A peptide is a strand of amino acids.
• collagen (KAHL-ah-jen) a type of body protein from which
connective tissues such as scars, tendons, ligaments, and the
foundations of bones and teeth are made
187
190. 190
Foods Grams per serving
Fruits and vegetables 0-3g
Fats and oils Almost none
Milk group 8-10g
Nuts and beans 12g
Meat/fish/poultry 7g
Protein in Foods
191. High-quality
- Complete proteins
- Contain all essential amino acids
- Animal proteins
Low-quality
- Incomplete protein
- Low in one or more essential amino acid
- Cannot support body growth
- Plant sources
• All-or-none principle in protein synthesis
• Limiting amino acids
• Complementary proteins
Dietary Protein
192. Animal Protein
• Contribution to our diet
~70% of our protein intake
• Top 5 contributors of protein in U.S. diet:
- Beef
- Poultry
- Milk
- White bread
- Cheese
• Worldwide, 35% comes from animal sources
196. Health and Plant Proteins
• Heart healthy
• Cancer-fighting
• Bone health
• Better glucose control
• Soy and menopausal symptoms
197. Plant Sources
• Provide protein, minerals, and dietary fiber
• Contain no cholesterol
• Limited saturated fats
• High fiber
- Time needed to adjust to the higher fiber load
198. Denaturation of Proteins
Heat / acid / alkaline / enzymes
Results in alteration of the protein’s three-dimensional structure
199. Digestion of Protein in the Stomach
• Denatured
- By cooking and acid in the stomach
• Gastrin
- Stimulates the release of acid and pepsin
• Pepsin
- Breaks down proteins
200. • Pancreatic enzymes:
- Trypsin secreted(among others) into the
intestines
Peptones → peptides → amino acids
• Small peptides and amino acids
- Ready for absorption
Digestion of Protein in the Small intestine
204. Functions of Proteins
• Building blocks of body components
• Fluid balance maintenance
• Acid/base balance (contribute to)
• Building blocks of hormones and enzymes
• Immune function
• Gluconeogenesis
• Energy yielding (non-preferred source)
• Provides highest feeling of satiety after meal
206. RDA for Protein
0.8 gm of protein / kg of healthy body weight
70 kg x 0.8 g protein = 56 g protein
kg healthy body weight
207. • Increased by ~10-15 gm /day for pregnancy
• Endurance athletes
May need 1.2 – 1.7 gm/kg healthy weight
• Provide about 8-10% of total kcal
• Most of us eat more than the RDA for protein
• Excess protein cannot be stored as protein
RDA for Protein
208. Is a High-Protein Diet Harmful?
• Low in plant foods (fiber), vitamins, phytochemicals
• High in saturated fat and cholesterol
• Burden on the kidney
• May increase calcium loss in the urine
• Excessive intake of processed red meat is linked with colon
cancer
• Increase urine production – increase risk for dehydration
212. Vegetarian Diets
Why become a vegetarian?
• Vegans
• Fruitarians
• Lactovegetarians
• Lacto-ovovegetarians
• Concerns for infants and children
213.
214. Can revert or prevent many diseases?
214
https://www.youtube.com/watch?v=gz6BuF
xvYz0
215. Vegetearian Diets
• Need for complementary proteins
• Nutrient concerns
- Vitamin B12
- Iron
- Zinc
- Calcium
- Omega-3 fatty acids
216. The Foundations of Human
Nutrition
Course #: 550101
Lecture 7
Water and minerals
Haneen S. Dwaib BSc, MPH, PhD
Haneen.dwaib@paluniv.edu.ps
217. Water
• 50%-70% of body weight
• Muscle contains 73% water
- Fat contains ~20%
• Intracellular fluid
- Fluid within the cells
• Extracellular fluid
- Fluid outside the cells
218. Fluid Balance
• Water shifts freely in and out of
cells
• Controlled by electrolyte
concentration
• Osmosis
• Intracellular water volume
- Depends on intracellular
potassium and phosphate
concentrations
• Extracellular water volume
- Depends on extracellular sodium
and potassium concentrations
219. Functions of Water
• Body temperature regulation
- Water absorbs excess heat
- Body secretes fluid via perspiration
- Skin is cooled as perspiration evaporates
• Removal of body waste via urine
- Urea excretion
- Sodium excretion
- Avoid concentrated urine
• Amniotic fluid, joint lubricants, saliva, bile
220. Are You Drinking Enough?
• Fluid recommendation:
9 cups for women and 13 cups for men
221. Thirst Mechanism
• Not reliable
• Concerns for infants, older adults, athletes
• Athletes
- Weigh before and after training session
- Consume 2 ½ - 3 cups for every ½ kg lost
• Illness (vomiting, diarrhea, fever)
222. Ignoring the Thirst Signal
• Shortage of water increases fluid conservation
• Antidiuretic hormone
- Released by the pituitary gland
- Forces kidneys to conserve water (reduce urine flow)
• Aldosterone
- Responds to drop in blood pressure
- Signals the kidney to retain sodium (water)
223. Hydration
• Loss of 1%-2% of body weight in fluid
- Thirst signal
• Loss of 2% or more of body weight causes muscle
weakness
- Lose significant strength and endurance
• Loss of 10%-12%
- Heat intolerance
• Loss of 20%
- Coma and death
224. Too Much Water
• Overburden the kidneys
• Low blood electrolyte concentrations
• Blurred vision
• Water Intoxication At the other extreme from
dehydration, water intoxication occurs when too much
plain water floods the body’s fluids and disturbs their
normal composition. Most adult victims have
consumed several gallons of plain water in a few hours’
time. Water intoxication is rare, but when it occurs,
immediate action is needed to reverse dangerously
diluted blood before death ensues.
226. Minerals
• Various functions in the body
• Major Minerals
- Require >100 mg /day
- Calcium, phosphorus, magnesium, chloride, potassium,
sodium, sulfur
• Trace Minerals
- Require < 100 mg/day
- Iron, zinc, selenium, iodine, cupper, fluoride, chr, Mn, Mo
227.
228. Bioavailability of Minerals
• Degree of absorption
• Presence of binders and fiber
• Animal products are better absorbed
• Plants depend on mineral content of soil
• Refinement lowers mineral content
• Mineral-mineral competition
• Vitamins-mineral competition
230. Sodium
• Table salt (NaCl) (40% sodium, 60% chloride)
• 95% of ingested sodium is absorbed
• Positive ion in extracellular fluid
• Aldosterone regulates sodium balance
• Key for retaining body water
• Excretion regulated by the kidneys
• Muscle contraction
• Conduction of nerve impulses
231. Sodium Deficiency
• Deficiency is rare
• Persistent vomiting/ diarrhea
• Excessive perspiration
- Losing 2-3% of body weight
• Depletion of sodium in the body
• Signs of deficiency:
- Muscle cramp, nausea, vomiting, dizziness, shock, coma
• Normally kidney will respond by conserving sodium
232. Food Sources of Sodium
• Most sodium is added by food manufacturers and
restaurants
• In Processed foods: bread, cheese, lunch meats, crackers,
tomato sauce, chips, soups..
• Check Sodium content listed on the labels
When following a salt restricted diet replace salt
with lemon juice,
vinegar, spices, condiments etc…
233.
234.
235. Sodium Needs
(Don’t memorize)
• Adequate Intake is 1500 mg for adults
• Body only needs 200 mg to function
• Daily Value is 2400 mg/day
• Upper Level is 2300 mg
• Typical intake is 4700 mg/day
• Sodium-sensitive individuals should restrict intake
236. Potassium
Positive ion in intracellular fluid
Functions:
- Fluid balance
- Nerve impulse transmission
• Associated with lowering blood pressure
• 90% of potassium consumed is absorbed
• Low blood potassium
- Muscle cramps, confusion, constipation, irregular heart beat, heart failure
237. Potassium Sources and Needs
Potassium Sources:
• Mostly Fruits and vegetables, whole grains, meats, dried beans,
milk.
Potassium Needs: (Don’t memorize)
• Adequate Intake is 4700 mg/day
• Daily Value is 3500 mg/day
• Typical intake is 2000-3000 mg/day
• Diuretics may deplete potassium
• Excess potassium is excreted by the kidneys; no Upper Level
240. Calcium
• 99% is in bones and teeth
• Makes up 40% of all the minerals present in the body
241. Absorption of Calcium
• Amount in body is dependent on amount absorbed
• Requires slightly acidic environment and vitamin D
• Absorbed in upper part of small intestine
• Normally absorb 25% of calcium in food
• Increase to ~60% during time of need pregnancy, infancy
242. Decreased Absorption of Calcium
• Rapid intestinal motility
• High fiber intake
• Excess phosphorus
• Vitamin D deficiency
• Polyphenols (tannins) in tea
• Menopause
• Aging
243. Blood Calcium is Regulated
• Blood level is maintained at the price of bone calcium
• Blood level can be maintained despite inadequate calcium intake
• Setting stage for future bone fractures
244. Functions of Calcium
• Bone formation and maintenance
• Blood clotting
• Nerve impulse transmission
• Muscle contraction
245. Building Higher Bone Mass
• Adequate diet
• Healthy body weight
• Normal menses
• Weight-bearing physical activity
• Moderate intakes of protein, phosphorus, sodium, caffeine
• Non-smoker
• Lower use of certain medications
247. Calcium Needs
(Don’t memorize)
• Daily Value is 1000 mg/day
• Adequate Intake is 1000 -1200 mg/day for adults
• Adequate Intake is 1300 mg/day for adolescents
(9-18 yrs. old)
• Average intake: 800 mg/day for women and 1000 mg/day for men
• Upper Level is 2500 mg/day
248. Calcium Supplements
• Recommended for people who cannot incorporate Ca into
their diets
• Not recommended with high-zinc meal
• Calcium carbonate (40% calcium)
- For those with ample stomach acid
- Found in antacids
• Calcium citrate (21% calcium)
- Enhances absorption due to acidity content
- Recommended for older adults
250. Phosphorus
• Major ion of intracellular fluid
• Bone and tooth strength
• Component of various compounds
• Absorption is based on body’s need (70%-90%)
• No disease associated with deficiency
• May contribute to bone loss in older women
• Vitamin D enhances absorption
251. Phosphorus Sources and Needs
• Wide variety of foods
• Food sources include:
Dairy, bakery products, eggs, sodas, meats
• Some from food additives
• Difficult to limit intake
• Daily Value is 1000 mg
• Deficiency unlikely
• High phosphorus intake with low calcium intake contributes to bone loss
253. Magnesium
• Absorption based on body’s needs (normally 40%-60%)
• Kidneys regulate blood concentration of magnesium
• 60% is stored in the bones
254. Functions of Magnesium
• Aids in many enzyme reactions
• Potassium and calcium metabolism
• Proper nerve and cardiac functions
• May dilate arteries
- Decrease blood pressure
• May prevent heart rhythm abnormalities
Magnesium Deficiency
• Develops slowly
• Irregular heartbeat
• Weakness, muscle spasms, disorientation, nausea, vomiting, seizures
255. Too Much or Too Little Magnesium
• Magnesium loss
- Heavy perspiration
- Long-standing diarrhea or vomiting
- Alcoholism
- Disorientation, weakness, muscle pain, poor heart function
• Toxicity
- Caused by medications
256. Magnesium Sources and Needs
• Whole grains, vegetables, nuts, seeds
• Hard tap water
• Dairy, chocolate, meat
• Daily Value is 400 mg
• Average intake is lower than the RDA
• Upper Level is 350 mg (nonfood source)
RDA for women is 310 mg/day
RDA for men is 400 mg/day
260. The Trace Minerals
• Needed in much smaller amounts
• Essential for health
• Difficult to study
- Only trace amounts in the body
• Animal sources of mineral are generally better absorbed
261. Iron
• Found in minute amounts in every cell
• 18% is absorbed
• Heme iron: Heme found in animal products, better absorbed
• Nonheme iron: cereals, vegetables, Not well absorbed
Meat protein factor may aid in nonheme absorption
Vitamin C enhances absorption nonheme iron
262. Absorption of Iron
• Determined by body’s need
• Iron storage in intestinal cells
• Absorbed in an acidic environment
• Hindered by phytic acid, oxalic acid, high fiber, high calcium,
polyphenols
263. Functions of Iron
• Hemoglobin in red blood cells
- Transports oxygen and carbon dioxide
- High turnover, high demand for iron
• Myoglobin in muscle cells
• Electron transport chain
• Enzyme cofactor
• Immune function
• Drug-detoxification pathway
264. Iron-Deficient Anemia
• Most common form of anemia
• Low levels of hemoglobin and hematocrit
• Insufficient intake and stores
• Reduction in
- Production of red blood cells
- Oxygen-carrying capacity
265. Iron Deficiency
Anemia
• Most at risk:
- Infant, toddler, chronic blood loss, vegans, runners, and women of
childbearing years
- Pica in women and children
• Signs:
- Paleness, brittle nails, fatigue, poor temperature control, poor growth
Iron Toxicity
• Serious, especially for children
• Signs:
– Diarrhea, constipation, nausea, abdominal pain
– Causes death due to respiratory collapse (shock)
• Hemochromatosis
– Genetic disease
– Iron deposit that can lead to organ damage
– May go undetected until organ damage at 50-60
267. • Red meat (all types, grilled, broiled, baked)
• Chicken, fish
• Beans (lentils…)
• Green leafy vegetables (spinach, kale…)
• Fortified cereals and grains
Food Sources of Iron
268. Iron Needs
(Don’t memorize)
• RDA is 8 mg/day for adult male
• RDA is 18 mg/day for female age 19 to 50
• Daily Value is 18 mg
• Average intake exceeds RDA for men; low for some women
• Upper Level is 45 mg/day
269. • heme (HEEM) the iron-containing portion of the hemoglobin and myoglobin molecules.
• nonheme iron dietary iron not associated with hemoglobin; the iron of plants and other sources.
• tannins compounds in tea (especially black tea) and coffee that bind iron. Tannins also denature proteins.
• phytates (FYE-tates) compounds present in plant foods (particularly whole grains) that bind iron and may prevent its absorption.
• iron overload the state of having more iron in the body than it needs or can handle, usually arising from a hereditary defect. Also called
hemochromatosis.
• iron deficiency the condition of having depleted iron stores, which, at the extreme, causes iron-deficiency anemia.
• iron-deficiency anemia a form of anemia caused by a lack of iron and characterized
by red blood cell shrinkage and color loss. Accompanying symptoms are weakness, apathy, headaches, pallor, intolerance to cold, and inability to
pay attention. (For other anemias, see the index.)
• anemia the condition of inadequate or impaired red blood cells; a reduced number or volume of red blood cells along with too little hemoglobin
in the blood. The red blood cells may be immature and therefore too large or too small to function properly. Anemia can result from blood loss,
excessive red blood cell destruction, defective red blood cell formation, and many nutrient deficiencies. Anemia is not a disease but a symptom
of another problem; its name literally means “too little blood.”
• hemoglobin (HEEM-oh-globe-in) the oxygen-carrying protein of the blood; found in the red blood cells (hemo means “blood”;
globin means “spherical protein”).
• myoglobin (MYE-oh-globe-in) the oxygen-holding protein of the muscles (myo means “muscle”).
269
271. Zinc
• Absorption
- Influenced by the foods consumed
- Animal sources are better absorbed
- Dependent on body’s need
• Factors that decrease absorption
- Presence of phytic acid
- Competes with copper and iron for absorption
276. Selenium
• Readily absorbed
• Excreted through the urine and feces
• Functions:
– Co-factor for glutathione peroxidase
– Protects the heart and other cells from oxidative damage
– Works together with vitamin E
– Aids in cancer prevention?
• Thyroid hormone metabolism
278. Selenium Sources
• Fish, meat (organ meats), egg, milk, shellfish
• Grains, seeds, nuts (dependent on soil content)
Selenium Needs(Don’t memorize)
• RDA for adults is 55 µg/day
• Daily Value is 70 µg
• Average intake exceeds RDA (and Daily Value)
279. Selenium Toxicity
• Upper Level is 400 µg/day
• Garlicky breath
• Hair loss
• Nausea, vomiting
• Weakness
• Rashes
• Cirrhosis of the liver
280. Iodide
• Iodine in foods–fortified salt
• Functions:
– Supports thyroid hormone synthesis
– Regulates metabolic rate, growth, development
• Deficiency:
– Thyroid gland enlarges (goiter) due to low intake
– Cretinism, stunting of fetal growth and mental development as a
result of low iodide in maternal diet
281. Iodide Sources
• Iodized salt ̶ ½ tsp. meets RDA
• Saltwater fish, seafood, dairy, grains
• Sea salt is poor source
- Iodide lost during processing
• Plant source dependent on soil content
Iodide Needs
• RDA and Daily Value are 150 µg/day
- Only 50 µg needed to prevent goiter
• Average intake exceeds RDA
282. Iodide Toxicity
• Upper Level is 1.1 mg/day
• Thyroid hormone synthesis is inhibited
• “Toxic goiter” results
• Consumption of seaweed poses risk
283. • goiter (GOY-ter) enlargement of
the thyroid gland due to an
iodine deficiency is simple
goiter; enlargement due to an
iodine excess is toxic goiter.
• cretinism (CREE-tin-ism) severe
mental and physical retardation
of an infant caused by the
mother’s iodine deficiency
during pregnancy
283
284. Fluoride
• Role in prevention of dental caries
- Helps tooth enamel resist acid
- Inhibits bacterial growth
Fluoride Sources
• Fluoridated water
–~0.2 mg/cup
–1 ppm
• Tea, seafood, seaweed
• Toothpaste
Fluoride Needs
• Adequate Intake is 3.1 -3.8 mg/day for adults
285. Fluoride Toxicity
• Mottling of teeth in children
• Limit toothpaste to pea size for children
– High amounts can weaken teeth
• Upper Level is 1.3-2.2 mg/day for children
• Upper Level is 10 g/day for older children and adults
286. Chromium
• Enhances insulin action
• Deficiency related to Type 2 diabetes
• Low intake:
- Impaired glucose tolerance
- Elevated blood cholesterol and triglycerides
Egg yolk, bran, whole grain, cereal, organ meat, meat, beer
Plant sources dependent on soil content
Adequate Intake is 25 - 35 µg/day for adults
Chromium Sources, Needs and toxicity
No toxicity from foods
No Upper Level
Exposure to chromium in environmental waste sites
290. The Foundations of Human
Nutrition
Course #: 550101
Lecture 8
Energy Balance and
Weight Control
Haneen S. Dwaib BSc, MPH, PhD
Haneen.dwaib@paluniv.edu.ps
292. Worldwide obesity has nearly tripled since 1975
In 2016
• 39% of adults are overweight
• 13% of adults are obese
Energy balance
293. Nasreddine et al, 2012
Obesity
(%)
Prevalence of Obesity in Lebanon
294. • Positive energy balance
Energy consumed greater than expended
• Negative energy balance
Energy consumed less than expended
• Energy balance
Energy consumed = Energy expended
Energy balance
296. • Energy intake (Food and beverages)
• Energy output
- Basal metabolism: energy needed at rest
- Energy for physical activity
- Thermic effect of food
Energy balance
298. • Minimum energy expended to keep a resting, awake body alive
• ~ 60-70% of total energy needs
• Includes energy needed for maintaining:
✓ Heartbeat
✓ Respiration
✓ Body temperature
• Amount of energy needed for basal metabolism varies between
individuals
• Approximately 1 kcal/minute
Energy balance
Basal Metabolism
299. • Body surface area (weight, height)
• Body temperature
• Lean body mass
• Calorie intake
• Thyroid hormone
• Nervous system activity
• Use of caffeine and tobacco
Basal Metabolism
Factors that Influence Basal Metabolism
• Gender
• Age
• Pregnancy
300. • Increases energy expenditure
• More activity, more energy burned
• Lack of activity is a major cause of obesity
Physical Activity
301. Thermic Effect of Food (TEF)
• Energy used to digest, absorb, and metabolize food nutrients
• “Sales tax” of total energy consumed
• ~5-10% above the total calories consumed
• TEF is highest for protein > carbohydrate > fat
302. Thermogenesis
• Increase in Non-voluntary physical activity
- Triggered by overeating (Increases sympathetic nervous system
activity)
- Cold conditions
• Examples of non voluntary activities:
- Fidgeting
- Shivering
- Maintenance of muscle tone
- Maintenance of posture
• Resists weight gain
303. Energy needs
• 25-30 kcal/ kg body weight
• Minus 100 kcal for every 10 years above 40
• ~1600 kcal: sedentary women, elderly
• ~2200 kcal: children, teenage girls, active women, most men
• ~2800 kcal: active men, very active women, teenage boys
304. Estimated Energy Requirement (EER)
• Men 19 years and older:
EER= 662-(9.53 x AGE) + PA x (15.91 x WT + 539.6 x HT)
• Women 19 years and older:
EER= 354 - (6.91 x AGE) + PA x (9.36 x WT + 726 x HT)
- PA = physical activity estimate
- WT = weight in kg
- HT = height in meters (inches / 39.4)
305. ACTIVITY LEVEL PA (MEN) PA (WOMEN)
Sedentary
(no exercise)
1.00 1.00
Low Activity (walks the
equivalent of
~2 miles/day)
1.11 1.12
Active (walks the
equivalent of
~7 miles/day)
1.25 1.27
Very Active (walks the
equivalent of ~17
miles/day)
1.48 1.45
Physical Activity Estimate
306. What is a Healthy Body Weight?
• Current height/weight standards
- Weight associated with health and longevity
- May not be the healthiest weight for some individuals
• Review of family history
• Personal weight history
• Healthy lifestyle contribution
307. A Healthy Body Weight
• What is the lowest weight maintained for more than a year?
• What weight was maintained without constantly feeling hungry?
• Establish a “personal” healthy weight
309. BMI: Overweight and Obesity
Body weight status BMI
Underweight < 18.5
Healthy weight 18.5-24.9
Overweight 25-29.9
Obese 30-39.9
Severely obese >40
310. Perspective on Weight
• Aim for personal healthy weight
• Avoid unrealistic goals
• Listen to body’s cues (for hunger)
• Eat a healthy diet
• Be physically active
• “Size acceptance”
311. Obesity
• Excessive amount of body fat
- Women > 35% body fat
- Men > 24% body fat
• Increased risk for health problems
• Are usually truly overweight
312. • Bioelectrical impedance
- Low-energy current that measures the resistance of electrical flow
- Fat is resistant to electrical flow; the more the resistance, the more
body fat
• DEXA (dual x-ray photon absorptiometry)
- X-ray body scan that allows for the determination of body fat
- Most accurate but expensive
Estimation of Body Fat
316. Upper-body obesity, “Apple shape”
• Associated with
- Cardiovascular disease, hypertension, type 2 diabetes
- Testosterone and excessive alcohol
- Abdominal fat is released into the liver and promotes
inflammation in the body
• Defined as
- Waist measurement of > 102 cm for men
- Waist measurement of >88 cm for women
Estimation of Body Fat
317. Body Fat Distribution
Lower-body obesity, “Pear shape”
- Encouraged by estrogen and progesterone
- Fewer health risks than upper-body obesity
- After menopause, upper-body obesity more common
319. Why Diets Don’t Work
• Obesity is a chronic disease
- Treatment requires long-term lifestyle changes
• Dieters are misdirected
- More concerned about weight loss than healthy lifestyle
- Unrealistic weight expectations
320. Looking for a Sound
Weight-Loss Program?
• Seek advice from a Registered Dietitian
• Control calorie intake
• Increase physical activity
• Acknowledge need for lifelong changes to maintain healthy weight
322. • Sedentary society---requires less calories
• Low-fat, high-fiber approaches
- Most successful in long-term studies
• No diet has a “metabolic advantage”
• Keep a food log (portion size awareness)
• Read food labels
Control Calories
323. • Important for weight maintenance
• Promotes steady weight loss
- Expends 100-300 kcal while controlling calories
• Boosts self-esteem
• Add weight resistance
- Increase lean body mass
- Increase fat use
- Increase bone health
- Increase metabolic rate
Regular Physical Activity
324. • 60 minutes/day to maintain body weight
• 60-90 minutes/day for maintenance of weight loss
• Pedometer
- Goal 10,000 steps a day
Physical Activity Recommendations
325. • Body fat contains 3500 kcal per ½ a kilogram
• Fat storage (body fat plus supporting lean tissues) contains 3500 kcal
per half a kilo
• Must have an energy deficit of about 3500 kcal to lose half a kilo per
week
What it Takes to Lose a Pound
326. Do the Math
To lose half a kilo, you must create a deficit of 3500 kcal
So to lose half a kilo in 1 week (7 days), try cutting back on your kcal
intake and increase physical activity so that you create a deficit of
about 500 kcal per day
- 500 kcal x 7 days = - 3500 kcal = ~ ½ Kg of weight
day week loss in 1 week
327. • Rate of loss
• Flexibility
• Intake
• Behavior modification
• Overall health
Sound Weight Loss Program
329. Chain-Breaking
• Breaking the link between two behaviors
• These links can lead to excessive intake
Stimulus Control
• Altering the environment
- Minimize the stimuli for eating
• Putting you in charge of temptations
330. Cognitive Restructuring
• Changing your frame of mind regarding eating
• Replacing eating due to stress with “walking”
• Forming a plan of action
– Response to a situation
• Rehearsing appropriate responses
– The pressure of eating at parties
Contingency Management
331. Self-Monitoring
• Tracking foods eaten and conditions affecting eating
• Understanding your eating habits
• Prevent relapse
– Occasional lapse is fine, but take charge immediately
– Continue to practice newly learned behavior
– Requires “motivation, movement, and monitoring”
• Have social support
– Encouragement from friends/ family/ professionals
Weight Maintenance
332. Orlistat (Xenical)
• Inhibits (lipase) fat digestion
• Reduces absorption of fat by 30% in the small intestine
• Dietary fat is deposited in the feces, with resulting side effects
• Must still control fat intake
• Malabsorption of fat-soluble vitamins
• Supplement needed at bedtime
• Alli---Low dose of Orlistat, available OTC
334. Very Low-Calorie Diets (VLCD)
• Recommended for people >30% above their healthy weight
• 400-800 kcal per day
• Low carbohydrate and high protein
• Cause ketosis
• Lose ~3-4 pounds a week
• Health risks include cardiac problems and gallstones
Require careful physician monitoring
336. Adjustable Gastric Banding
• Reduces opening from esophagus to stomach by gastric band
• Decreases amount of food eaten
• Band can be inflated or deflated
337. Sleeve
• Most common surgical procedure for treating severe obesity
• Reduces the stomach size
- From 4 cups to 1 oz (shot glass size)
• Overeating will result in rapid vomiting
• Smaller stomach promotes satiety earlier
• 75% will lose ~50% of excess body weight
339. Criteria for Bariatric surgeries
• BMI > 40
• Obese for > 5 years
• No history of alcoholism
• No history of major psychiatric disorder
• Costly procedure
• Follow-up needed after procedure loss
• Requires major lifestyle changes
340. Fad Diets
• Promote quick weight loss
• Limited food selections
• Use of testimonials
• Cure-alls
• Recommend expensive supplements
• No permanent lifestyle changes advocated
• Critical of the scientific community
341. Types of Popular Diets
• Low or restricted carbohydrates (High protein
and/or high fat diets)
• Carbohydrate focused diets
• Low-fat approaches
• Novelty diets
• Meal replacements
343. Underweight is Also a Problem
• BMI of <18.5
• Associated with increased deaths, menstrual dysfunction,
pregnancy complications, slower recovery from illness/surgery
Treatment for Underweight
• Intake of energy-dense foods (energy input)
• Encourage regular meals and snacks
• Reduce activity (energy output)
• Increase portion size
• Strength training
344. The Foundations of Human
Nutrition
Course #: 550101
Lecture 9
Food Safety
Haneen S. Dwaib BSc, MPH, PhD
Haneen.dwaib@paluniv.edu.ps
345. • Most people get food poisoned on a regular basis; however,
they do not correlate their sickness to food.
• Most illnesses are caused by a foodborne Virus or Bacteria.
• “Mabrood” and other used phrases are nothing but myths!
Foodborne illness is caused from eating
contaminated food
346.
347. Food Poisoning Symptoms
Common Symptoms
• Nausea
• Vomiting
• Diarrhea
• Fever
• Abdominal Pain
Other Severe Symptoms
• Meningitis
• Paralysis
• Death
349. Food Contamination
• Raw meat, eggs, seafood
• Unpasteurized milk
• Undercooked food
• Cooked food and left at room temperature (>2h)
• Water contaminated with sewage
• Fruits and vegetables grown in contaminated soils
• Human contamination through improper hygiene
350. Bacteria. What is it ?
• Harmful bacteria do not generally affect the taste, smell,
or appearance of a food.
• One cannot tell that a food has been mishandled or is
dangerous to eat.
It may look and smell fine, and still be
unsafe!
354. Food Safety: Shopping
Once you purchase food, the
safety of that food also
becomes your responsibility!
When shopping for food, you
should choose, pack and
transport it carefully to make
sure it is safe to eat.
355. Take special care when it comes to high risk foods
TAKE THEM HOME IMMEDIATELY!
• Seafood
• Meat, Poultry (Chicken, Turkey)
• Dairy products (Milk, Eggs etc.)
• Cold cuts such as salami and ham
• Cooked rice, cooked pasta
• Prepared salads such as coleslaw, pasta salads and rice salads
356. When shopping, DON’T BUY!
• Dented, swollen or leaking cans or containers
• Products with damaged or imperfect packaging
358. • Cracked eggs
• Fresh cut produce if not refrigerated or surrounded by ice
• Chilled or frozen foods that have been left out of the refrigerator
• Products soiled or mouldy
• Ready-to-eat foods left uncovered on counters
• Hot food, like takeaways, which are not steaming hot
• Anything where you have doubts about the quality!
When shopping, DON’T BUY!
359. SHOPPING TIPS TO KEEP IN MIND
• Stay away from any fresh produce that appears damaged
or bruised
• Check the dates on the packaging
360. SHOPPING TIPS TO KEEP IN MIND
MEATS, POULTRY AND FISH
• Look for packages that are cool to the touch and have no wear
or punctures.
• All meats should be refrigerated when purchased.
361. If food is not stored
properly, the bacteria
can multiply to
dangerous levels!
Food Safety: Storage
362. REFRIGERATOR :
• Your refrigerator should be set at 4 to 5 °C.
• Don't pack the refrigerator full - allow air to
circulate.
• Don’t put very hot food into the refrigerator.
(Wait until steam has stopped rising from the
food before putting it in the fridge.)
• Put hot food into shallow dishes or smaller
portions to help cool the food as quickly as
possible.
• Always store raw food in sealed or covered
containers at the bottom of the fridge.
• Keep raw foods below cooked foods, to avoid
liquid such as meat juices dripping down and
contaminating the cooked food or fresh
vegetables and fruits.
Food Safety: Storage
363. REFRIGERATOR
• Place meat, poultry and fish in the
coldest part of the refrigerator.
• Do not store eggs in door of
refrigerator due to temperature
fluctuations.
• Door higher temperatures
• Remove spoiled foods so bacteria
can't be passed to other foods.
• Use or discard refrigerated food on
a regular basis.
Food Safety: Storage
364. FREEZER
• Set your freezer at or below -18°C.
• Freeze leftovers that won't be eaten for a few days.
• Store frozen food items in this order (top to bottom):
– Vegetables
– Fish
– Beef
– Pork/Ground Meat
– Poultry
Freezing will
NOT kill all
bacteria that
might have
been in the
food before it
was frozen
Food Safety: Storage
365. GENERAL STORAGE
• Place newer items behind or below older ones (FIFO)
• If a food item is taken out of its original container, label it accordingly.
Food that comes in packages, cans and jars can become high risk
after you open it.
Food should not be stored in open cans!
• Canned/Vacuumed Packed Foods: If one end of a can pops when the other
end is pushed, or if there are signs of moisture or leakage, do not attempt to
use the product.
• Dry Foods: Flour, cereal, sugar etc. These products should be kept at least
six inches off the floor and stored in clean, dry areas, away from wall.
Food Safety: Storage
366. Food Safety: Cooking
The way we cook our food is as important as the
way we prepare and store it.
Inadequate cooking is a common cause of food
poisoning.
Most foods, especially meat, poultry and eggs, should
be cooked thoroughly to kill most food poisoning
bacteria.
367. How you cook food is very important!
• Cook meats, sausages, whole chickens or stuffed
meats right through to the centre.
You should not be able to see any pink meat and the
juices should be clear.
• Cook steak, chops and whole roasts to your
preference as food poisoning bacteria are mostly
on the surface.
• Cook white fish until it flakes easily with a fork.
• Cook foods made from eggs such as omelettes
and baked egg custards thoroughly. (salmonella)
• Throw out any high risk cooked food left at room
temperature for more than two hours.
Food Safety: Cooking
368. Food Safety: Chilling
Bacteria spreads fastest at room
temperature.
Chilling food properly is one of the most
effective ways to reduce the risk of
foodborne illness.
369. Chill Promptly. Cold temperatures slow the growth of harmful bacteria.
• Chill all perishable foods in the fridge and frozen food in the freezer as
soon as you get them from the store or it is delivered to you.
• Chill all food (including vegetables) that is not served straight away.
Never let raw meat, poultry, eggs, cooked food, or cut fresh fruits or
vegetables sit at room temperature more than two hours before
putting them in the refrigerator or freezer.
• Chill all cooked food within 30 minutes of cooking.
• Regularly checking that fridges and freezers are working properly.
Food Safety: Chilling
370. Frozen food can be thawed:
1- In the fridge overnight
2- Under running cold water
3- In the microwave (then cook immediately)
4- Cook it directly
• Thaw food in a container large enough to collect all liquid.
• Defrosted food shouldn't be refrozen.
• Do not thaw food at room temperature.
Food Safety: Thawing
372. Bacteria can spread
through out the kitchen
and get on hands,
cutting boards, knives
and other utensils and
equipment !
Frequent cleaning can
keep that from
happening.
Food Safety: Cleaning
373. Food safety : cleaning
• Wash your hands with warm water and soap for 20 seconds before and
after handling food.
• Turn away and cover your mouth if you sneeze or cough near food, and
always wash your hands afterward.
• Don't wash eggs - this could increase the potential for bacteria on the shell
to enter the egg.
• Wash the lids of canned foods just before opening them to prevent dirt
from getting into the food. Clean the can opener's blade after every use.
Cross contamination:
• Do not let raw meat or poultry juices touch ready-to-eat foods during
preparation.
• Don't put cooked foods on the same plate that held raw meat or poultry.
Food Safety: Cleaning
374. How to wash fruits and vegetables
• Scrub with a brush
• Wash fruits and vegetables under running water then soak in vinegar
To decrease Pesticides
• Peel fruits and vegetables
• Remove outer leaves
• Trim visible fat from meat poultry and fish
• Discard fats and oils in broths and pan drippings
Food Safety: Cleaning
376. The Foundations of Human
Nutrition
Course #: 550101
Lecture 6
Vitamins
Haneen S. Dwaib BSc, MPH, PhD
Haneen.dwaib@paluniv.edu.ps
377. Vitamins
• Essential organic substances
• Produce deficiency symptoms when missing from diet
• Yield no energy
• Basic functions
- Facilitate energy-yielding chemical reactions
- Function as co-enzymes
• Fat-soluble vitamins
• Water-soluble vitamins
378. Storage of Vitamins
in the Body
• Fat-soluble
- Not readily excreted (except
vitamin K)
• Water-soluble
- Generally lost from the body
(except vitamins B-6 and B-12)
- Excreted via urine
• Vitamins should be
consumed daily
- Occasional lapse is harmless
379. Vitamin Toxicity
• Fat-soluble vitamins
- Can accumulate in the body
• Water-soluble vitamins
- Some can cause toxicity
• Mostly likely due to supplementation
380. Preservation of Vitamins
• Decreased vitamin content
- Improper storage
- Excessive cooking
- Exposure to light, heat, air, water, and alkalinity
• Eat foods soon after harvest
• Freeze foods not consumed within a few days
• Blanching destroys enzymes
- Slows down vitamin degradation
382. Fat-Soluble Vitamins Overview
• Dissolve in organic solvents
• Not readily excreted
- Can cause toxicity
• Absorbed along with fat
• Fat malabsorption
- May cause deficiency
• Transported with fat
- In lipoproteins
383. Vitamin A
• Narrow optimal intake range
• Preformed
- Retinoids
- Found in animal products
• Proformed
- Carotenoids
- Found in plant products
384. Functions of Vitamin A
• Promote vision
- Night blindness
• Promote growth
• Prevent drying of the skin and eyes
- Xerophthalmia
• Promote immune function and resistance to bacterial infection
• Cardiovascular disease prevention
• Cancer prevention
• Acne medication
387. Toxicity of Vitamin A
• Large intake of vitamin A (preformed)
- Over a long period
- Use of Accutane and Retin-A
• Signs and symptoms
- Bone/muscle pain, loss of appetite, skin disorders,
headache, dry skin, hair loss, increased liver size,
vomiting
- Fetal malformation
- Possible permanent damage
389. Vitamin D
• Prohormone
• Derived from cholesterol
• Synthesized from sun exposure
- Sunscreen SPF >8 decreases synthesis 95%
- Expose hands, face, arms 2-3 x/week for 5-10 minutes each time
(more for darker skin)
• Activated by enzymes in liver and kidneys
• Deficiency can cause disease
391. Functions of Vitamin D
• Regulates blood calcium
- Regulates calcium + phosphorus absorption
- Reduces kidney excretion of calcium
- Regulates calcium deposition in bones
• Influences normal cell development
- Linked to reduction of breast, colon, and prostate cancer
392. Role in Bone Formation
• Causes calcium + phosphorus to deposit in the bones
• Strengthens bones
• Rickets is the result of low vitamin D
Breastfed infants with little sun exposure
• Osteomalacia (soft bones)
- Rickets-like disease in adults
- Bones lose minerals and become porous
393. Food Sources of Vitamin D
• Fatty fish (salmon, herring)
• Fortified milk
• Some fortified cereal
• Supplements needed for
breastfed infants
394. Toxicity Warning
• Vitamin D can be very toxic, especially in infancy and
childhood
• Upper Level is 50 µg/day
• Results in:
- Over-absorption of calcium (hypercalcemia), increase
calcium excretion
- Calcium deposits in organs and blood vessels
- Growth retardation
397. Other Functions of Vitamin E
• Protects double bonds in unsaturated fats
• Improves vitamin A absorption
• Deficiency
- Breakdown of cell membranes
- Hemolysis
- Nerve degeneration
399. Toxicity of Vitamin E
• Toxic effects
- Inhibit vitamin K metabolism and anticoagulants
- Possible hemorrhage
- Muscle weakness, headaches, nausea
401. Vitamin K (“Koagulation”)
• Synthesized by bacteria in the colon and absorbed
• Role in coagulation process
• Role in calcium-binding potential
402. Food Sources of Vitamin K
• Liver
• Green leafy vegetables
• Broccoli
• Peas
• Green beans
• Resistant to cooking losses
• Limited vitamin K stored in the body
403. Adequate Intake for Vitamin K
• Excess vitamins A and E
- Interferes with vitamin K
• Newborns
- Routinely injected with vitamin K
- Breast milk is a poor source
• Toxicity unlikely; readily excreted
405. Overview of Water-Soluble Vitamins
• Dissolve in water
• Generally readily excreted from body
• Subject to cooking losses
• Function as coenzymes
• Participate in energy metabolism
• 50-90% of B vitamins are absorbed
• Marginal deficiency more common
• Enrichment Act
406. Thiamin (B1)
• Sensitive to alkalinity and heat
• Coenzyme form used in energy metabolism
• Surplus is rapidly lost in urine; non-toxic
407. Food Sources of Thiamin
• Whole grains / Enriched grains
• Wheat germ
• Green beans
• Dried beans
• Seeds
• Milk
• Organ meats
409. Riboflavin (B2)
• Coenzyme participates in energy-yielding metabolic
reactions
• Deficiency
- Inflammation of mouth and tongue, dermatitis,
sensitivity to sun
• Non-toxic
412. Niacin (B3)
• Coenzyme used in energy metabolism
• Deficiency
- Pellagra
- 3 D’s (Dermatitis, Diarrhea, Death)
• RDA
- 14 mg/day for women
- 16 mg/day for men
• Toxicity
- Upper Level is 35 mg/day
413. Food Sources of Niacin
• Whole and Enriched grains
• Beef , Chicken/turkey, Fish
• tryptophan (amino acid) can be converted into
niacin
• Heat stable; little cooking loss
415. Pantothenic Acid (B5)
• Part of Coenzyme-A
- Essential for metabolism of carbohydrate, fat, & protein
• Deficiency rare
- Usually in combination with other deficiencies
417. Biotin
• Co-enzyme
- Metabolism of carbohydrate and fat
- Helps breakdown certain amino acids
• Deficiency–rare
- Scaly, inflamed skin
- Changes in tongue, lips
- Decreased appetite, nausea, vomiting
418. Food Sources of Biotin
• Cauliflower, egg yolk, liver, peanuts, cheese
• Intestinal synthesis of biotin contributes very little
• Avidin inhibits absorption
More than a dozen raw egg whites a day to cause this effect
419. Vitamin B-6
• Coenzyme forms
- Activate enzymes needed for metabolism of
carbohydrate, fat, and protein
- Synthesize nonessential amino acids
- Synthesize neurotransmitters
- Synthesize hemoglobin and White Blood Cells
429. Vitamin B-12
• Coenzyme
- Role in folate metabolism
- Red Blood Cell formation
• Deficiency
- Anemia
- Nerve degeneration and paralysis
430. B-12 Absorption
• Requires a protein from salivary gland
• Requires stomach acid and the intrinsic factor
• Absorbed in the last part of the small intestine
• About 50% of B-12 is absorbed
431. Food Sources of Vitamin B-12
• Synthesized by bacteria, fungi and algae
(Stored primarily in the liver of animals)
• Animal products
• Organ meat
• Seafood
• Eggs
• Milk and dairy
433. Vitamin C
• Synthesized by most animals
- Not by humans
• Decreased absorption with high intakes
• Excess excreted
- Diarrhea common
• Sensitive to
- Cooking/heat
- Iron, copper, oxygen
434. Functions of Vitamin C
• Synthesis of collagen
• Iron absorption
• Immune functions
• Antioxidant?
435. Deficiency of Vitamin C
• Scurvy
- Deficient for 20-40 days
- Fatigue, pinpoint hemorrhages
- Bleeding gums
- Weakness
- Fractures
- Associated with poverty
436. Food Sources of Vitamin C
• Citrus fruits
• Strawberries
• Kiwi
• Parsley
• Green pepper
• Cauliflower
• Broccoli
• Spinach
• Potatoes
437. RDA for Vitamin C
• 90 mg/day for adult males
• 75 mg/day for adult females
• Daily Value is 60 mg
• +35 mg/day for smokers
• Average intake 70-100 mg/day
• Upper Level is 2 g/day
441. Dietary Supplements
• Vitamins
• Minerals
• Herbs
• Amino Acids
• A dietary substance to supplement the diet
Can be marketed in US without FDA approval if:
- Reasonably safe
- Product must be labeled as a dietary supplement
442. Who needs Supplements
• Women in childbearing age (Iron and Folic acid)
• Pregnant and breastfeeding mothers (iron, Folic acid, Calcium)
• Women on strict diets(< 1200 cal/day)
• Elderly (calcium, Vit B12, Vit D)
• New born (Vit K injection)
• Children (Fluoride, Iron, Vit D)
• Strict vegans (Vit B12, Calcium, iron)
• Low fat diets
