Transcript Nutrition Basics

Nutrition Basics
• Food defined culturally:
– A person’s diet is the result of:
• Genetics - taste ability (PTC test)
• Personal life experiences
• Culture
• Nutrients: biological requirement
Nutrition Basics
• Nutrients: biological
requirement
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Carbohydrates
Protein - amino acids
Lipids - oils and fats
Vitamins
Minerals
Water
Nutrition Basics
• Role of Food/ nutrients
– Food - supplies nutrients: carbohydrate,
protein, vitamin, mineral, fat/oils
– Food/nutrients important for: growth,
development, reproduction etc
– Food/nutrition plays a major role in human
adaptation because:
• it is an independent stressor
• modifier of other stressors (disease)
Nutrition Basics
• Nutrients function to:
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Sustain life
Promote growth
Replace loss
Provide energy:
• growth, maintenance, work, respiration,
reproduction
Energy Intake
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Food freq. quest.
24-hr recall
Food records
Food weighing
Direct observation
Energy Expenditure
• Gas exchange calorimetry
• Heart rate monitoring
• Estimated from activity
– Motion sensors
– Activity diary
– Direct observation
• Doubly labeled water
(D218O)
Nutritional Status
• Clinical exam:
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Skin
Nails
Hair
Eyes
Mouth
Thyroid
Macronutrients
• Protein
• Carbohydrate
• Lipids (fats & oils)
Protein
• structural materials
• enzymes hormones
• source of amino acids used to make protein in
the body
• contributes to immune function
• can provide some energy can make glucose
from amino acids
• 20 aa used in human protein
– 9 are essential (they must be obtained from
food). Complete protein contain all essential
aa
Carbohydrates
• Historically nutritionists have classified
carbohydrates as either simple or complex,
however, the exact delineation of these
categories is ambiguous.
• Today, simple carbohydrate typically refers
to monosaccharides and disaccharides
complex carbohydrate means
polysacchrides (and oligosaccharides).
Carbohydrates: major functions
1. Providing energy and regulation of blood
glucose
2. Sparing the use of proteins for energy
3. Breakdown of fatty acids and preventing
ketosis
4. correct working of our brain, heart and
nervous, digestive and immune systems.
5. Fiber, which is also a form of carbohydrate, is
essential for the elimination of waste materials
and toxins
Lipds: Fats & Oils
• Production of fatty acids for the production of
phospholipids – in structure of cell membranes.
• Cholesterol is also made from fatty acids and is
used for prod of sex and adrenal hormones.
• Lubrication, especially in joints and around
muscles.
• Temperature regulation through the insulation
they provide. They are also important for the
transport of certain vitamins (fat-soluble
vitamins).
Types of Malnutrition
1. Undernutrition
A. Kwashiorkor
B. Marasmus
C. Micronutrient deficiencies
2. Over-nutrition
Vitamins
• Catalysts for metabolic processes
• Required in small quantities
• Absorption mechanisms
– fat soluble (A, D, E, K)
– water soluble (C, B complex)
• Storage capacity
– greatest for fat soluble vitamins, with potential for
overdosage
• Food sources
Vitamin A Deficinecy
• Night blindness,(earliest
manifestation)
– rhodopsin reduced in rods
– reduced ability to see in dim
light
• Early eye lesions
– conjunctival xerosis
• conjunctiva becomes dry,
thickened, wrinkled,
pigmented, loses shiny luster
– Bitot’s spots
• bilateral, triangular, raised
whitish plaques
• plaques appear as fine foam
with bubbles
Epidemiology-Vitamin A Deficiency
• Distribution
– Poor, rice-eating populations world wide
– W. Africa-spared; red palm oil, those eating small,
(entire), fish spared as vit A concentrates in liver
– Affluent societies; alcoholics, malabsorbtion
• Prevalence
– 251 million children <5 years with mild to moderate
deficiency
– 2-3 million children with xerophthalmia
• >50% become blind or have serious visual damage
• significant mortality from infection, decreased immunity
and decreased epithelial integrity
SCURVY
• Scurvy is the term to describe ascorbic
acid or vitamin C deficiency in the diet,
manifest by
– weakness,
– anemia,
– spongy swollen gums,
• James Lind a British naval surgeon born
1739, is credited with having empirically
evaluated the effect of diet on scurvy,
(the first reported controlled clinical trial!)
Vitamin D Deficiency
Rickets: childhood
• Dental changes in
childhood rickets
– delayed dental eruption
• small, pointed teeth
• susceptible to early caries
• Complications
– growth retardation
– pulmonary infection
– high childhood mortality
Osteomalacia: adults
Prevention-Vitamin D
Deficiency
•Sunlight- education re: swaddling
•Vitamin D supplementation
–prophylactic supplementation of
the institutionalized
Summary- Vit D deficiency
• Rickets- childhood
• Osteomalacia- adults
•Primary skeletal changes due to bone
softening
•Lack of cutaneous synthesis or intake
and utilization of Vit D required for
calcium absorbtion
Pellagra Diagnosis
• Clinical- Four D’s
– dermatitis,
diarrhea,
dementia, death
• Laboratory
– urine N’-methylnicotinamide
PELLAGRA
• Clinical Presentation
– Dermatitis
• confluent over sun exposed
areas
• collar of Casal, dermatosis
around neck
– Progression
• erythema, desquamation,
hyperpigmentation, atrophy
– Seasonality
• worst after sun exposure
PELLAGRA MANIFESTATIONS
• Gastrointestinal
– stomatitis, glossitis, gastritis, enteritis, malabsorbtion
(edematous, painful mucosa, desquamation, glossy- scarlet
tongue)
• Neuropsychiatric (late stage)
– confusion, irritability
– depression, delusions, suicidal ideation
• there were asylums in the southern US for victims of central
nervous system pellagra/ niacin deficiency
Mineral Deficiencies
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Iron- anemia
Iodine- goiter
Fluoride-caries
Trace elements
Iron Metabolism
• Etiology
– insufficient dietary iron (most common)
• absorbtion/binding may be affected
– anemia from blood loss
• hookworm and other parasites in developing world
• Prevalence
– ~50% of developing world may have iron deficiency
– 56 - 70% of pregnant women in developing world
• compared to 18% of pregnant women in developed world
• associated with 50% of maternal deaths, retards fetal growth
– 60% of children < 5 yrs in developing world
ANEMIA
Definition
• Anemia is defined as a decrease in the concentration of circulating
red blood cells or in the hemoglobin concentration and a
concomitant impaired capacity to transport oxygen.
WHO Diagnosis
• Hemoglobin below 12gm/dl in non pregnant females, 11gm/dl for
pregnant women, 11gm/dl in pre school children.
• Etiology
– insufficient dietary iron (most common)
• absorbtion /binding may be affected
– anemia from blood loss
• hookworm and other parasites in developing world
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High Iron Bioavailability
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Blood products
Beef, pork, chicken, fish
Liver, spleen, kidney
Oysters, clams, mussels
Spinach, alfalfa shoots
Good Iron Content
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Whole grains
Bean, peas, soybeans, chickpeas
Seeds (pumpkin, sesame, sunflower)
Blackstrap molasses
Peanuts, betel nuts, dates, raisins
Egg yolk
Crickets, termites, grasshoppers
Iron Deficiency
• Insufficient intake
– poor and vegan diet
– malabsorbtion
• Blood loss
– pregnancies
– parasites; hookworms,
schistosomes, malaria
Clinical Manifestations
• Mild anemia
– diffuse, non-specific symptoms, pallor
• Moderate anemia
– glossitis, anorexia, heartburn, constipation, fatigue
– Pica, bizarre food cravings, (ingeation of clay, or ice
• Severe anemia
– congestive heart failure, (high output)
– maternal morbidity/mortality
– susceptibility to infection
Iodine Deficiency: Goiter
Iodine Deficiency
• Requirement- sources
– 150 micrograms/day in adolescent
and adults
– seafood, soil, milk products
– iodized salt, 60% of world’s salt is
iodized, but not targeted to those at
risk
• Prevalence
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1 billion at risk
655 million with goiter
11 million with cretinism
high mountainous areas; away from
sea
Goiter Treatment & Prevention
• Iodine intake
– iodized salt
– iodized oil
Endemic Cretinism
• Severe iodine deficiency
• S.America, Asia, South Pacific
•Related to maternal hypothyroidism
• Neurologic developmental damage
• Mental retardation, deaf-mutism,
•Short stature, thick skin,protuberant
thick tongue, shuffling gait
Trace elements-fluoride
• Fluoride
– mineral nutrient for teeth &
skeleton
• Deficiency
– dental caries
Common Nutrition-Related Problems
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Arteriosclerotic heart disease
Hypertension
Diabetes
Morbid obesity
Important Nutritional Problems
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Protein-energy malnutrition
Nutritional anemias
Vitamin A deficiency (xerophthalmia)
Iodine deficiency disorders