AHS 201 - Final Exam
Chapter #9
Water
Water comprises 50%-70% of the human body
Every cell, tissue, and organ contains some water
Essential for life
Water in the body
Intracellular fluid
Fluid contained within a cell (⅔)
Extracellular fluid
Fluid present outside the cells (⅓)
Electrolytes
Charged ions that transfer electrical current
In extracellular: sodium (Na+) and chloride (Cl-)
In intracellular: potassium (K+) and phosphate (PO4-)
f
Osmosis
A passage of water through a membrane, from a less electrolyte concentrated compartment to a more concentrated compartment.
Water shifts in and out of cells
Body control
Water is the universal solvent
Many different solutes can be dissolved in water
Water transports nutrients and wastes
Water is a medium for chemical reactions.
Water contributes to body temperature regulation
Water is resistant to temperature changes
Perspiration allows evaporation through the skin allowing heat to be released and cooling off the body.
Water Intake
AI: 11 cups for women and 15 cups for men
Based on intake from fluids and food.
Fluid alone is 9 and 13yhn
Water Output
Urine accounts for the greatest source of output
Water is lost through perspiration
Fluid lost through respiration is referred to as insensible water loss (difficult to measure)
Small amount of water is lost daily through feces
Fluid Conservation
When the body registers a shortage of available water, it increases fluid conservation.
Regulated by kidneys, blood vessels, and brain hormones
Antidiuretic hormone
Dehydration
Simplest way to determine if water intake is adequate is to observe urine color
Thirst and Hydration Status
In most cases, drinking fluids in response to the thirst sensation will result in adequate hydration.
The thirst mechanism can lag behind actual water loss.
Too much water?
If water intake far exceeds the kidneys processing ability, overhydration, and sodium dilution (water intoxication, and hypernatremia
Sources of Water
Americans consume 42 gallons of bottled water per capita per year
EPA regulates and monitors public water supplies
FDA regulates bottled water
Fluoride is added to many municipal water supplies to prevent dental caries
Minerals: Essential Elements for Health
Major mineral: need >100mg per day
Trace Mineral: need <100mg per day
Absorption and Storage of Minerals in the Body
Minerals can compete with each other for absorption
Some beneficial vitamin mineral interactions
Vitamin C enhances non heme iron absorption
Active Vitamin D improves calcium absorption
Electrolytes
Sodium and potassium
Sodium: salt is 40% sodium, and 60% chloride. Nearly all americans exceed dietary requirements for sodium - reducing sodium is a major public health campaign
Functions of sodium: electrolyte - attracts water
Fluid balance
Kidneys import filter
Nerve impulse conduction
Avoiding too much sodium (UL = 2300 mg) high intakes often lead to hypertension
Minerals and Hypertension
Estimated 1 in 5 adults has hypertension
Primary hypertension
Secondary hypertension
Why Control Blood Pressure?
Prevention of cardiovascular disease, kidney disease, strokes and related declines in brain function, sudden death
Contributors to Hypertension: risk factors include family history, age, atherosclerosis, inactivity, excess alcohol and obesity
Other Minerals and Blood Pressure
Diets rich in calcium, potassium, and magnesium, can decrease blood pressure. DASH diet (dietary approaches to stop hypertension).
Getting enough Calcium
Acidic environment necessary for Ca absorption
Depends on the presence fo the active form of Vitamin D
Adults absorb -30% of the calcium in the foods
RDA: 1000 mg (19-50 years old) 1200 mg (women older than age 5., and men and women over age 70)
Osteoporosis
Peak bone mass in early 20’s
Risk factors include gender, ethnicity, body type, family history, smoking, low physical activity, alcohol
Iron
Forms of Iron in Food
Heme Iron
Animal tissues
.readily absorbed
Nonheme Iron
Plant sources
Less efficiently absorbed, absorption dependent on body needs
Getting enough iron
Animal sources are most bioavailable
Other sources: ready to eat breakfast cereals beans, and animal products
Acidic environment helps absorption
Vitamin C enhances nonheme iron absorption
Iron Deficiency
Most common nutrient deficiency worldwide
Iron deficiency anemia is sever iron deficiency
Decreased O2 carrying capacity
Zinc Functions
Growth and development
Wound healing
Taste perceptions
Getting Enough Zinc
High protein diets, animal sources
Vegetarians may need 50% more
Deficiency: delayed wound healing, impaired immunity, reduced sense of taste and smell
Fluoride (F)
Prevents dental caries
Increases protein synthesis in bone building cells
Most fluoride comes from oral hygiene products and the water supply
Idione (I)
Functions: supports thyroid hormone synthesis
Food sources: Iodized salt, dairy products, grain products
Definiciency results in goiter: an enlargement of the thyroid gland as it attempts to take up more iodide from bloodstream
Also results in
Selenium
Functions: aids antioxidant, helps maintain cell membrane integrity, activation of thyroid hormone
Animal sources: fish, meat, shellfish, eggs
Plant Sources: brazil nuts, grains and seeds grown in selenium rich soil
Energy Balance and Weight Control
Energy balance and weight control
68.8% of North American adults are overweight; 34% of total population is obese.
Westernized diets, (high fat high sugar) increasing in popularity
Excess weight increases likelihood of many health problems
BMI categories
Underweight is under 18.5
Healthy weight is 18.5-24.9
Overweight is 25--29.9
Obese is 30-39.9
Morbidly obese is greater than 40
Estimating Body Fat Content and Diagnosing Obesity
Acceptable amount of body fat is 25%-31% for women and 18%-24% for men
obes
Indicators Weight is not Healthy
Hypertension
Elevated LDL cholesterol
Pattern of upper body fat distribution
Elevated blood glucose
Estimation of Body Fat
Underwater weighing is very accurate. Fat is less dense than lean tissue.
Central Obesity
Measure waist circumference women less than 35 inches
Men less than 40
Energy Balance - energy intake matches energy expanded
Energy Intake
Average adult is 8 pounds heavier than just 10 years ago
Cheap cost
Availability of palatable food in vending machines
Drive throughs, social gatherings, fast food restaurants, supersized portions.
Basal Metabolism - minimum amount of calories body uses to support itself in a fasting state when resting and awake in warm, quiet, environments (60-75% of total energy needs)
Factors that Influence Basal Metabolism
Body surface area (weight and height
Lean body mass
Gender
Body temperature
Stress
Age
pregnancy
Thermic Effect of Food (TEF)
Energy used to digest, absorb, and metabolize food nutrients.
5-10% above the total calories consumed
Adaptive Thermogenesis
Non Voluntary physical activity
Triggered by overeating
Fidgeting and shivering
Maintenance of muscle tone
Maintenance of posture
Estimates of Energy Needs
Control of Calorie Intake
Average calorie need per day
Female: 1800-2400
Male: 2200-3000
Higher for more active people
Sedentary society requires less calories
Conquering the Weight Loss Plateau
Healthy weight-loss takes time
Early weight loss includes fluid and fat
May be increasing muscle mass
Treatment of Severe Obesity
BMI greater than or equal to 40
Very low calorie diet (VLCD)
400-800 kcal per day, often in liquid form
Bariatric Surgery
Adjustable gastric banding
Opening from the esophagus to stomach is reduced by a hollow gastric band.
Gastroplasty (Gastric bypass, stomach stapling)
Performed on stomach to limit volume to 30 millimeters
Sleeve gastrectomy (gastric sleeve)
Surgical reduction of stomach by about 75%
Lipectomy
Removing “problem” local fat deposits
Suctioning out fat through thin tube
Risk of infection, skin depression, blood clots
May result in 4 to 8 pounds
Costs 1.8k per site, range from 2600-9000
Underweight
Body mass index below 18.5
Caused by a variety of factors: cancer, infectious disease, digestive tract disorders, excessive dieting or physical activity
Associated with increased death rate