BIO 105-03

Dietary supplements
– dietary supplements are not strictly regulated by FDA
— manufacturers not required to prove safety or efficacy of supplement claims
– dietary supplements and ergogenic aids may improved performance, but can have side effects
ergogenic = a substance used to improve athletic performance

– creatine
— research data mixed regarding enhancement of performance
— improves hi-intensity, short-duration activities (like weight training) that rely on anaerobic metabolism
— supposed to increase the amt of creatine phosphate in muscle

– caffeine
— enhances athletic performance, mostly during endurance events
— stimulates CNS, breakdown of muscle glycogen, may increase fatty acid avaialbility
— improves hi-intensity, short duration activities (like weight training) that rely on anaerobic metabolism

– anabolic steroid
— anabolic effect
— testosterone-based substances that promote muscle growth and strength
— androgenic effect (testosterone-promoting)
— hormone imbalance causes undesirable side effects in both men and women and health risks

– growth hormone
— little research on efffects on athletic performance, results mixed
— reduces body fat but not muscle strength
— excess can cause acromegaly and serious health issues

– erythropoietin and blood doping
— increase oxygen-carrying capacity of the blood by increasing # of blood cells
— can increase blood viscosity, increase risk of stroke and heart of attack
– sports bars, shakes and meal replacements may provide benefits
— convenient sources of carb and protein but more expensive than whole foods
— may include extra emounts of vitamins and minerals not needed

Disease of the day: female athlete triad
– eating disorder with 3 major components
— disordered eating: harmful eating behaviors in order to lose weight or maintain a lo weight
— amenorrhea: absence of 3-6 consecutive menstrual cycles due to insufficient energy intake
— osteoporosis: resulting from amenorrhea and poor diet; increases risk for stress, hip and vertebral fractures

Bio 105 Lecture 16 Notes

I. Hunger
A. Basic info
– the physical need for food
– food insecurity: chronic inability to secure adequate amounts of nutritious food to meet needs
— in 2004, 12% of households were food insecure in USA and 4% classified as “hungry”
— worldwide, 2 billion were food insecure
— current global food production exceeds the needs of the population
B. Causes of Domestic Hunger
– often caused by poverty, illness or lack of opportunity
— ex: poverty – 12% of US population at or below poverty level ($13,200/yr for married couple or single mother with 1 child)
— ex: obesity among food insecure is common, less nutritious foods can be less expensive, higher in calories
— ex: chronically ill or disabled less likely to earn steady income and at risk for poor diet
C. Causes of Global Hunger
– often caused by inequality, political conflict, crop failure, population overgrowth
— ex: war and regional conflicts disrupt agriculture and food distribution, caused more than 35% of food emergencies between 1992-2003
— ex: insects destroy about 33% of world food supply each year
— ex: most of world population growth occurs in developing and underdeveloped countries
II. Starvation
A. Basic info
– the result of a severe/total lack of nutrients needed for the maintenance of life
– results from the inadequate intake of nutrients or the inability to metabolize or absorb nutrients
– complete starvation in adults leads to death within 8-12 weeks
— consists of approx 3 stages
— starved adults may lose as much as 50% of their normal body weight
B. Causes
– eating disorders
– intentional fasting
– coma
– stroke
– inability to obtain food (famine, child abuse, aftermath of war /disaster, lost in wilderness or desert areas)
– severe gastrointestinal disease
C. Stages
1. Stage 1
– blood glucose levels are maintained thru production of glucose from glycogen, protein & fat
– glycogen only lasts a few hours
– when glucose used up:
— fatty acids used as majority of energy for most cells
— some proteins are made into glucose for CNS
2. Stage 2
– can last for several weeks
– fat is primary energy source
– liver breaks down fatty acids into ketone bodies
– after a week, the brain starts to use ketones in addition to glucose for energy
— conserve glucose and proteins
3. Stage 3
– only occurs in prolonged starvation
– fat reserved depleted
– proteins become primary source of energy
— muscles rapidly deplete
— nonessential proteins used first
— once nonessential proteins are used up, the essential proteins are used
– eventually cell function stops = death
D. Overall Effect
– metabolic rate is decreased
– many organs begin to shrink
— villi in gut shrink = less capacity to absorb nutrition
— stomach shrinks = decreases appetite, hunger
– ability of the body to consume normal volumes of food decreases
– total body shutdown & death
E. Symptoms
– shrinkage of vital organs – heart, lungs, ovaries, testes and gradual loss of their functions
– chronic diarrhea
– anemia
– decreased ability to digest food because of lack of digestive acid production
– immune deficiency: often people die of infection first
F. Minnesota Starvation Experiment
1. Basic info
– human starvation experiment by Ancel Keys at UMinn
– during WWII
– determine how to help/re-feed Eurozone after war
– learn physiological and psychological effects of long-term starvation
2. Experimental Conditions
– 36 healthy white males, ages 22-33
— volunteers from conscientious objectors
– main objectve = characterize the physical and mental effects of starvation on healthy men
– observed under
a. Baseline
– 3200 calories/day
— 3 mos
b. Semi-starvation
– 6 mos
— diet similar to Euro hungry: potatoes, turnips, rutabagas, dark bread, macaroni
— walk 22miles/week, expend 3000 cal/day
— goal to lose at least 25% of initial weight
c. Nutritional rehabilitation
– various cal/day (minimum 2200 cal/day)
— 2 mos>
— men randomly assigned to 1 of 4 energy intake groups
— each energy level was subdivided into 2 protein levels, and each protein level into 2 vitamin levels
3. Side Effects
– decreased sex drive
– reduction in muscle mass and consequent weakness
– lowered body temp combined with extreme sensitivity to cold
– irritability and difficulty with mental concentration
– swelling from fluid under the skin
4. What was learned
– detailed bok of results: The Biology of Human Starvation
— immediate pamplhlet for aid agencies
– need protein and extra cal (~4000 cal/day) to rehab starvation
– full recovery took 2 mos – 2 years
– equation to determine calorie intake to gain/lose specific amount of weight
— “Key’s forumla”
— used today in the therapeutic treatment of nutritional disorders

Clicker Questions
When fatty acids are broken down, what energy molecule is made?
1.Glucose
2.Ketones
3.Glycogen
4.Glycerol

What eating disorder is similar to the experiences of the men in the Minnesota experiment?
1.Anorexia nervosa
2.Bulimia nervosa
3.Binge eating disorder
4.Night eating syndrome

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