This document provides an overview of nutrition, including the study of nutrients and how the body uses food. It defines nutrients and their main functions, describes the digestive process and absorption of nutrients, and discusses vitamin and mineral needs. It also covers energy and protein requirements, nutritional diseases, food additives, and dietary supplements. Key topics include the six categories of nutrients, recommended daily intakes, vitamin and mineral deficiencies, fiber, processed foods, and functional foods.
2. Nutrition
the study of food and how the body uses it
Function of Nutrients:
1) supply energy
2) supply materials for building and
replacing body tissues
3) supply other substances needed for
various life processes
3. Nutrition
• Nutrients:Nutrients: the components of food and drink
that provide growth, replacement, and energy:
1. Carbohydrates
2. Lipids
3. Proteins
4. Vitamins
5. Minerals
6. Water
• DigestionDigestion: the hydrolysis of starches, fats, and
proteins into smaller units that can be
absorbed and metabolized.
5. Digestive Tract
• breakdown of food is done through a
series of enzyme-catalyzed reactions
• CHO start breaking down into
maltose and disaccharides in the
mouth by salivary amylase
• pepsin begins the breakdown
of protein into polypeptides
• acids are neutralized
• CHO to monosaccharides and
absorbed
• polypeptides to amino acids and
absorbed
• triglycerides to FAs and glycerol
6. Digestion Continued…
• Bile acids are like soaps. They have a polar and
nonpolar groups that aid water soluble lipase and
the incorporation of fats into chylomicrons for
transport. They are synthesized in the liver and
stored in the gallblader
• Lipase cleaves triglycerides to fatty acids and
glycerol
• Fatty acids, glycerol, amino acids,
monosaccharides are absorbed in the small
intestine and travel through the blood stream to the
liver for further modification
8. Carbohydrates Proteins Fats
Mouth Salivary amylase
Disaccharides
Maltose
Stomach Pepsin
Polypeptides
Small
Intestine
Pancreatic enzymes
Simples sugars
Glucose
Pancreatic
enzymes
Amino acids
Lipase
Bile salts
Glycerol
FAs
Bloodstream
Liver Glycogen Body proteins Body fats
9. Calorimeter
• Food energy is measured in Calories (capital C)
1 Cal = 1 kcal = 1000 cal = 4180 joules
• a Calorie is defined
as the amount of
energy required to
raise 1 kg of water 1°C
•Measured in a bomb
calorimeter
10. Calculating the Caloric Value
of Food
Carbohydrate = 4 Cal per gram
Proteins = 4 Cal per gram
Fats = 9 Cal per gram
13. Recommended Daily Intake:
Adults: 0.8 g per kg of body weight
Children and Pregnancy: 1.5-2.0 g per kg body weight
Complete Protein - contains all essential amino acids
-meat, eggs, dairy, fish
Incomplete Protein - missing one or more essential
amino acids
-legumes and grains combined make a complete
protein
Proteins
14. Proteins
– Gelatin, which is denatured collagen, is an
incomplete protein because it lacks Trp, and is low
in Ile and Met.
– Corn protein is low in Lys and Trp.
– Rice is low in Lys and Thr.
– Wheat protein is low in Lys.
– Legumes are low in Met and Cys.
– Soy protein is very low in Met.
Protein complementation:Protein complementation: a diet in which two or
more proteins complementation each other’s
deficiencies; for example:
– grains + legumes (rice + beans)
15. Fats • recommended 30% of diet
-10% monounsaturated
-10% saturated
-10% unsaturated
Essential Fatty acids:
Omega-3
EPA, DHA, linoleic
Omega-6
Arachidonic acid, α-linolenic
• EPA, DHA, AA are 20
carbon hormone-like
fatty acids that play an
important part in the
immune function
17. Energy Needs
Woman 2000 Cal
Men 2200 Cal
-physical activity and lifestage affects energy
needs
-need to burn 3500 Cal to lose 1 pound
Basal Caloric Requirements -the requirements
for a resting body
18.
19. Vitamins
-Organic compounds required in small
amounts for normal metabolism and good
health
- not a source of energy
Water soluble - C and Bs
-must be replenished everyday
-Difficult to overdose
Fat soluble - A, D, E, K
-does not need to be replenished everyday
-can cause toxicity
24. Vitamin Absorption and Storage
• All absorption takes place in the small intestine
• Fat-soluble vitamins
– Are absorbed in the duodenum
– Storage
• Vitamin A is mainly stored in the liver
• Vitamins K and E are partially stored in the liver
• Vitamin D is mainly stored in the fat and muscle tissue
• Can build up in body to point of toxicity
25. Vitamin Absorption and Storage
• Water-soluble vitamins
– Absorbed with water and enter directly into the
blood stream
– Most absorbed in the duodenum and jejunum
– Most are not stored in the body
– Excess intake excreted through the urine
– Important to consume adequate amounts daily
– Dietary excesses can be harmful
28. Water-Soluble
Vitamins
Fat-Soluble
Vitamins
Absorbed in the Small Intestine Small Intestine
Hydrophobic or
Hydrophilic
Hydrophilic Hydrophobic
Absorbed into the Blood Lymph
Stored in the body Not Generally Yes
Can build up and
become toxic
Not Generally Yes
Need to consume
daily
Yes No
29. Bioavailability
• Varies based on
– Amount in food
– Preparation
– Efficiency of digestion and absorption of food
– Individual nutritional status
– Natural or synthetic
• Fat-soluble vitamins are generally less
bioavailable than water-soluble vitamins
• Vitamins from animal foods are generally
more bioavailable than those in plant foods
30.
31.
32. 32
vitamin D
• A prohormone synthesized
from cholesterol
• Vitamin D3 = cholecalciferol
• Found in animal products
• Vitamin D2 = egocalciferol
• Found in plants and fortified
foods
35. • Time spent outdoors
• Amount of skin exposed
• Skin color
• Clothing
• Body fat
• Latitude
• Season and time of day
What affects your vitamin D
level?
37. Childhood rickets
• Epidemic with industrialization in 19-20th
centuries
• With discovery of vitamin D and
fortification, rickets was almost entirely
eliminated
• Until now…
39. • 40-90% of US community dwelling elderly
• 50% of premenopausal women
• 50% of Hispanic and black adolescents
• 48% of French preteens
• 30-50 % of adults in Saudi Arabia and
UAE
• 73 % of pregnant women taking prenatal
vitamins
…are DEFICIENT
40. How to get vitamin D...
• 100 IU/d raises level by about 1 ng/mL
• Sunlight 3000 IU/10 minutes
• Oily fish 300 IU/3 oz
– Salmon, sardines, mackerel, tuna
• Mushrooms 100 IU/3 oz
• Fortified drinks 100 IU/8 oz
– Milk, orange juice, yogurt, cereals
41. Updated Recommendations In Process
• Studies suggest that the daily vitamin D intakes
should be much higher than 400 IU/d.
• Daily intakes in the range of 800 to 1000 IU/d
should be strongly considered.
• Although there are concerns regarding vitamin D
toxicity, side effects at intakes exceeding the
current upper limit of 2000 IU/d have not been
reported to date.
• Assessment of vitamin D status with serum
measurements of 25(OH) vitamin D levels for a
broader range of patients should be encouraged.
42. Vitamin Deficiency
Scurvy - vitamin C (ascorbic acid) deficiency
-bleeding gums, vomiting, weight loss, anemia, poor
wound healing
Beri beri - vitamin B1 (thiamine) deficiency
-stiffness of limbs, heart disease, mental disorders,
paralysis of limbs
Pellagra - vitamin B3 (niacin) deficiency
-reddening and drying of skin, gastrointestinal and
nervous system disorders
43. blindness - vitamin A (retinol) deficiency
-night blindness, scaly and hard skin, eye
degeneration
-retinol is required for the generation of
rhodopsin, a photosensitive material
Rickets and Osteomalacia - vitamin D
(calciferol) deficiency
-required for the absorption of Ca and P
-skeletal problems, knock knees, protruding
forehead
-Rickets in children
-Osteomalacia in adults
Vitamin Deficiency cont….
44. Minerals
-defined as those elements, other than carbon,
oxygen, hydrogen, and nitrogen that are
needed for normal growth and maintenance
Major or Macrominerals - those required in
amounts of 1 gram or more
Ca, P, K, Na, Cl, Mg,
Trace or micromineral - those required in
amounts less than 1 gram
Cu, Co, Z, Fe, I, F, Se
45. Minerals
Phosphorus Balancing calcium in diet 800-1200 mg
Potassium
Sodium
Calcium
Chloride ion
Povides membrane potential
O smotic pressure
Bone formation; hormonal function;
blood coagulation; muscle contraction
O s motic pressure
Mineral Function
Magnesium
Iron
Zinc
Copper
Manganese
Chromium
Molybdenum
Cobalt
Selenium
Iodine
Fluorine
Cofactor in enzymes
O xidative phosphorylation;
hemoglobin
Cofactor in enzymes; insulin
O xidative enzymes cofactor
Bone formation
G lucose metabolism
Protein synthesis
Component of vitamin B12
Fat metabolism
Thyroid glands
Enamel formation
3500 mg
2000-2400 mg
800-1200 mg
1700-5100 mg
280-350 mg
15 mg
12-15 mg
1.5-3.0 mg
2.0-5.0 mg
0.05 - 0.2 mg
0.075-0.250 mg
0.05 mg
0.05-0.07 mg
150-170 µg
1.5-4.0 mg
RD A
47. Fiber - indigestible carbohydrates
-lowers risk of cardiovascular disease,
diabetes, colon cancer, diverticulitis and
obesity
• absorbs water and promotes frequent bowl movements
• fermented in the Large intestine by microbes
• lowers LDL cholesterol
1) Soluble
2) Insoluble
• slows gastric emptying
• causes satiety
• adds fecal bulk
48. Problems with Processed Food
• nutrients are lost in processing
• some but not all nutrients are
added back (Enriched)
• Fortified is when other
ingredients are added
that were not originally
the food
• are lower in fiber
• processed foods are
digested more quickly and
lend to weight gain
49. Nutritional Diseases
Kwashiorkor - protein deficiency
-often provides enough calories
-common b/w the ages of 1-4 b/c of
premature weaning
51. Nutritional Diseases
Anorexia Nervosa- a psychological
disorder characterized by low body weight
and poor body image
Bulimia Nervosa- psychological disorder
characterized by periods of binging and
purging
-often eat over 20,000 Cal
52. Nutritional Diseases
Obesity - excessive weight gain that is
associated with heath concerns and
increased risk of mortality
-characterized by a BMI of greater than 30
BMI (body mass index) = weight in kg
divided by the square of the height in m
-25% of Americans are obese
-60% of Americans are overweight (BMI 25-
29.9)
53. Nutritional Diseases
Diabetes - condition in which body is
unable to utilize glucose in a normal way
Type I - an auto immune disease that
results in the permanent destruction of
insulin producing beta cells in the pancreas
Type II - metabolic disorder that is usually
characterized by insulin resistance, insulin
deficiency and hyperglycemia
-associated with obesity
-Increased prevalence
54. Food Supplements
- vitamins, minerals, herbal remedies, etc…
-$60 billion a year industry
-Balanced diet provides adequate needs
-Elderly, dieters, alcoholics, pregnant, lactation
may require supplementation
- often supplements are not in a form that is as
available as it is in food
58. Food Preservatives
-mostly used to prevent food spoilage
Antimicrobial:
Nitrites
-clostridium botulism
- identified as cancer-causing
Sulfites
-wine and dried fruit
-can cause allergic rxn
Others
-Na, K, Ca salts, benzoic acid, propionic acid, sorbic acid
59. Food Preservatives cont….
Antioxidants: added to slow the oxidative
process
-usually phenols
Butylated hydroxyanisole (BHA) and butylated
hydroxytoluene (BHT)
-Prevent oxidation of fats by combining with free radicals
Natural Antioxidants
-Vitamin E, Vitamin C, carotenoids, other polyphenols
-also stop oxidation by combining with free radicals
60. Chemical Structures of Flavorings
-largest class of food additive
-natural and
synthetic
-Mostly
aldehydes and
esters
-Many
synthetics
have not been
thoroughly
tested
66. What are functional
foods?
• International food information council “those
foods that provide health benefits beyond
basic nutrition”
Bioactive
Nutraceutical
• Considered non-essential for
growth and development
• Decrease risk of chronic diseases
67. dietary supplements
• Regulated as foods
• Safety of supplement regulated
by FDA only after they have
entered the market
• DSHEA states that a dietary
supplement is “adulterated”
only if it presents a
“significant or unreasonable
risk of illness or injury”
68. Dietary supplement health &
education act of 1994
Definition of a supplement:
“Is a product (other than tobacco) that is intended
to supplement the diet that bears or contains one or
more of the following dietary ingredients: a
vitamin, a mineral, an herb or other botanical, an
amino acid, a dietary substance for use by man to
supplement the diet by increasing the total daily
intake, or a concentrate, metabolite, constituent,
extract, or combinations of these ingredients.”
•Is intended for ingestion in pill capsule, tablet,
or liquid form
•Is not represented for use as a conventional food
or as the soled item of a meal or diet
•Is labeled as a “dietary supplement”
•Includes products such as an approved new drug,
certified antibiotic, or licensed biologic that was
marketed as a dietary supplements or food before
approval, certification, or license (unless the
Secretary of Health and Human Services waives this
69. the challenge of
assessing dietary
supplements
• Need surrogate endpoints!
• Example assessment of risk of cancer,
inflammation
• Bioactive components decrease
inflammation via multiple mechanisms, i.e.
activation of transcription factor and other
epigenetic regulations
• Act as antioxidant etc.
73. carotenoids
• Yellow and orange fruits, dark
green leafy vegetables
• α and β-carotene and β
cryptoxantin – precursor to Vitamin
A
• lycopene, lutein, and zeaxantin –
not precursors to vit A
• Foods rich in carenoids may be safer
than purified supplements
• Typical western diet contains about 6
mg/day of carotenoids, 60% from animal
74.
75. lycopenes
• accumulates in
certain tissues,
such as prostate
• Lycopene commonly
in plasma
associated with
LDLs
• Lutein and
zeaxantin have
high binding
affinity to HDLs
– accumulate in
macula lutea of
retina, act as
photoreceptors
77. Plant sterols &
stanols• Most abundant Sterols = β-
sitosterol, stigmasterol,
campesterol
• Inhibit growth of various forms of
lung, stomach, ovarian and breast
cancer.
•Stanols = sitostanol, campestanol
• Sterols essential component cell
membrane
• Have sterol ring – differ in side
chain.
• Stanols are saturated form of sterol
78. Sterols and stanols
cont…• Cholesterol lowing
effect by lowering
absorption
• FDA authorized
health claims –
must contain at
least 0.65 g of
plant sterols or
1.70 g stanol
esters (esters have
higher lipid solubility
and are more easily
incorporated into
foods)
• Typical diet .15
- .4 g/day of
sterols and stanols
• To achieve 1.5
79. Polyphenols
• 1) flavanoids,
2) phenolic acids
• Secondary metabolites
– more than 8000
• Hydroxyl groups might
provide reducing power or
antioxidant potential (ROS)
• Usually lots of conjugated
double bonds
• Usually in free form or Ο-
glycosides
80. Phytoestrogens
• Majority phytoestrogens
belong to 4 subclasses:
isoflavanoid,
coumestans,
isoflavones, lignans,
stilbenes
• Composed of a planar
aromatic ring system
with one or more
hyroxyl
• Phytoestrogens proposed
to mimic estrogen and
act as weak agonist,
promoting estrogen
• favorably affect
hormone-dependent
cancers, menopausal
symptoms, glycemic
control and weight
maintenance,
decrease thrombus
and platelet
aggregation, lower
TGL, LDL.
• Recommended as alt
to hormone
replacement therapy.
• No safety info
82. Phytoestrogens
cont…
• Founds in licorice,
kudzu, soy, red
clover, saw palmetto
• Wine, grapes and
peanuts good source of
resveratrol
• Flax seed, whole grain
products, vegies, tea
good source of
lignans.
• FDA approved health
claim of 25 g or more
83. Indole-3-carbinol
• A chemically,
mechanistically, and
phylogenetically separate
phytoestrogen is indole-3-
carbinol
• does not mimic estrogen,
but alters alters
estrogen
metabolism via a
different
mechanism.
• Acid condensate of I-3-C
binds to aryl hydrocarbon
receptor which is capable
84. Organosulfurs
• Contains a derivative of
cysteine called
alliin, released when allium
vegetables are crushed.
• the enzyme allinase produces a
lipid-soluble, unstable
intermediate called allicin that
decomposes to produce allyl
sulfides, including diallyl
sulfide (DAS, DAD and DATS)
• Onions, leaks, chives, scallions,
garlic (richest source)
85. Polyols
• Sugar alcohols are
used as sweeteners –
Xylitol, Sorbitol,
Mannitol
• Fewer calories (1.5 –
3 kcal/g) and lower
glycemic index due to
reduced absorption by
intestine
• Excessive consumption
of sugar alcohols
lead to osmotic
diarrhea – >50g of
86. Stevia
• A natural zero calorie South
American herb
• Steviol contains two hydroxyl
groups
• Sugar residues are esterified to
one or both of the –OH groups to
form glycosides which are 200 –
450 times sweeter than sucrose.
• Microflora in intestine release
sugars and steviol
• May lower blood pressure
91. 1. How does the body store energy?
2. How many Cal of energy are released 180 grams of
glucose are converted to CO2 and H2O?
3. There are 2 fatty acids that the body needs but cannot
synthesize. What are they?
4. What is meant by a complete protein?
92. 5. Are vitamins organic or inorganic?
6. Identify each vitamin.
a) tocopherol
b) calciferol
c) ascorbic acid
d) cobalamin
e) retinol
7. What are the fat soluble vitamins?
8. What is kwashiorkor?