Option D: Nutrition for sports, exercise and health

Question 1

State the typical pH values found throughout the digestive system (3)

Answer 1

Stomach: 1.0 to less than 4.0
Mouth: 5.5 to 7.5
Small intestine: 6.0 to 8.0

Question 2

Describe the function of enzymes in the context of macronutrient digestion (3)

Answer 2

1. ROLE AS CATALYST: accelerate ✨ the rate of chemical reactions involved in digestion, converting complex food substances into absorbable forms (allows optimal absorption).
2. PROTEIN BASED NATURE: activity is highest under optimum conditions of temperature and pH
3. SPECIFICITY OF ACTION: Each enzyme is designed to catalyze a specific reaction or act on a specific substrate.

Question 3

Explain the need for enzymes in digestion (2)

Answer 3

Need for INCREASING RATE OF DIGESTION at body temperature:
1. VITAL for maintaining an effective digestive process
2. important for athletes as it ensures nutrient availability for energy and recovery.

Question 4

List the enzymes that are responsible for the digestion of carbohydrates, fats and proteins from the mouth to the small intestine (6)

Answer 4

🍔 CARBOHYDRATES:
1. Salivary amylase (mouth)
2. Pancreatic amylase (pancreas)
→ break down starch into smaller molecules

🧈 FATS:
1. Pancreatic lipase (small intestine)
→ break down fats into fatty acids & glycerol
2. Bile (liver/gall bladder)
→ disintegrates fats, increasing surface area

🐟 PROTEINS:
1. Pepsin (stomach)
2. Trypsin (small intestine)

Question 5

Describe the absorption of glucose, amino acids and fatty acids from the intestinal lumen to the capillary network (4)

Answer 5

1. Cross the BRUSH-BORDER MEMBRANE (first barrier as they move from the intestinal lumen into the absorptive cell)
2. Pass through the cytosol of the absorptive cell (gel-like substance)
3. Cross the basolateral membrane
4. Glucose and amino acids enter the capillary network, and fats enter the lymphatic system.

Question 6

State the reasons why humans cannot live without water for a prolonged period of time (4)

Answer 6

1. Basic substance for all metabolic processes in the body, working as SOLVENT for reactions and HYDRATION source to enzymes
2. Regulates BODY TEMP through sweating and heat distribution in blood
3. Enables TRANSPORT of substances
4. Allows for the DISSOLVING and EXCHANGE of nutrients and metabolic end products 🗑️

Question 7

State what extracellular fluid is and where it can be
located throughout the body (7)

Answer 7

What is ECF?
A body fluid that is not contained in cells, but it facilitates communication between cells and the bloodstream.

Where is it found?
🩸 the blood plasma and lymph
👄 saliva
👁️👁️ fluid in the eyes
💦 fluid secreted by glands and the digestive tract
🧠 fluid surrounding the nerves and spinal cord
✋ fluid secreted from the skin and kidneys

Question 8

Explain that homeostasis involves monitoring levels of variables and correcting changes in levels by negative feedback mechanisms (5)

Answer 8

What is HOMEOSTASIS?
Body’s ability to maintain a stable internal environment despite external changes.

MONITORING LEVELS:
Water balance threatened: decrease in concentration of body fluid

Sensed by or response:
🧠 The hypothalamus: acts as a central processing unit, interpreting signals from various receptors and coordinating responses.
🌡️ Thermoreceptors for temperature
🧪 Chemoreceptors for chemical changes
🩸 Baroreceptors for blood pressure

Question 9

How does it correct change in fluid levels?

Answer 9

CORRECTING CHANGES IN LEVELS (negative feedback mechanisms)
1. Activate the SENSATION of THIRST 💦 increasing the need to hydrate

2. Secrete ANTIDIURETIC HORMONE (ADH) which causes kidneys to retain fluids and reduce urine production

→ These two mechanisms gain and retain water and the consequence is increased water availability in ECF

Question 10

Explain the role of the loop of Henlé in maintaining the water balance of the blood (4)

Answer 10

(In KIDNEY’S NEPHRONS) it is a critical structure in urine formation and water conservation, a key process in regulating body fluids.
→ Ascending limb (impermeable): allows salts
to be reabsorbed
→ Descending limb: water reabsorption

Question 11

Explain the role of the medulla in maintaining the water balance of the blood (3)

Answer 11

(Located in KIDNEYS) water moves from LOW
CONCENTRATION to HIGH CONCENTRATION that is central to water reabsorption, and adjusts
urine concentration. This is known as maintaining the medullary osmotic gradient.

Question 12

Explain the role of the collecting duct in maintaining the water balance of the blood (2)

Answer 12

Located in the TERMINAL PORTION of the
nephron, it responds to ADH, causing
the collecting duct’s walls to become
more permeable to water. This
increases water reabsorption.

Question 13

Explain the role of the ADH in maintaining the water balance of the blood (3)

Answer 13

When body fluid levels are low, receptors in the hypothalamus are stimulated. This stimulates the pituitary gland to release Antidiuretic Hormone. ADH acts on the kidneys, increasing re-absorption of water.

Question 14

Describe how the hydration status of athletes can be monitored (4)

Answer 14

1. ASSESSING URINE COLOR:
   → ⭐️ Light, pale-colored: good hydration
   → ⚠️ Dark yellow or amber: dehydration
2. VARIATION IN BODY MASS LOSS:
   By weighing Pre- and Post-Exercise 🏃‍♀️, Athletes can assess their hydration level. A weight reduction of more than 2% of mass post-exercise typically indicates significant dehydration.
3. URINE OSMOLARITY:
   Define? Concentration of solutes in urine. How concentrated an athlete’s urine is, reflecting their hydration status.
   → High urine osmolarity (high concentration of solutes) suggests dehydration
4. THIRST SENSATION 💧: An athlete’s perception of thirst can provide clues.

Question 15

Explain why endurance athletes require a greater water intake (6)

Answer 15

To SUPPORT 🔝 levels of physical exertion
1. ensuring efficient nutrient
2. maintaining body temperature
3. removal of metabolic waste products
4. oxygen transport to muscles

CAUSING…
+ energy expenditure => + hydration needed

Question 16

Discuss the regulation of electrolyte balance during acute and chronic exercise

Answer 16

Acute
IMMEDIATE RESPONSE: The body loses electrolytes through sweat. However, the kidneys adapting to the demands of physical activity.

Chronic
LONG-TERM EFFECT: Regular, prolonged exercise can change the body’s electrolyte conservation ability. The body ADAPS.

Question 17

DEFINE ELECTROLYTES

Answer 17

Minerals that carry an electric charge and balance: amount of water, body’s acid/base level, movement of nutrients, moving wastes out.

Question 18

Define the term basal metabolic rate (BMR)

Answer 18

The amount of energy EXPENDED by the body at REST in a neutrally temperate environment, after the digestive system has been inactive for about 12 hours.

Question 19

Explain the relationship between energy expenditure and intake (3)

Answer 19

(Energy intake 🥑 = energy expenditure 🚴‍♀️)
=> Weight remains

(Energy intake 🥑 > energy expenditure 🚴‍♀️)
=> Weight increases

(Energy intake 🥑 < energy expenditure 🚴‍♀️)
=> Weight decreases

Question 20

State the components of daily energy expenditure (3)

Answer 20

BASAL METABOLIC RATE (BMR)

THERMIC EFFECT OF PHYSICAL ACTIVITY → energy expended during any physical activity

THERMIC EFFECT OF FEEDING → energy used by the body to PROCESS FOOD (includes digestion, absorption of nutrients).

Question 21

Discuss the association between body composition and athletic performance (7)

Answer 21

DEFINITION of “Body composition”: body mass made up of fat mass and fat-free mass.
Fat-free mass (FFM) consists of lean mass and skeletal muscle mass.

Impact of EXCESS Fat:
+ body fat = reduced speed, agility, and endurance.
+ body fat = increase risk of overheating.

Optimized Fat-Free Mass:
+ muscle mass enhances strength, power, and endurance in sports.

Sport-Specific Composition: Different sports have varying ideal body compositions.

1. Long-distance runners 🏃‍♀️→ lower body fat (endurance)
2. Weightlifters 🏋️‍♀️→ higher muscle mass (strength)

Question 22

Discuss CONTROVERSIAL dietary practices employed by athletes to manipulate body composition (4)

Answer 22

CONTROVERSIAL!!!!!
1. Diet pills: non-prescribed that contain caffeine → increase HR and metabolism
2. Prescription pills: mimics LEPTIN, getting the message that the body is full.
3. Fad diets: Eliminate one or more of the essential food groups, or consume one type of food in excess at the expense of another.
4. Crash diets: Extreme version of fad diet. Not effective as it slows down the body’s metabolic rate - the body seeks to conserve energy and therefore weight loss is difficult.

Question 23

Discuss BODY COMPOSITION CHANGING dietary practices employed by athletes to manipulate body composition (3)

Answer 23

1. Calorie Restriction: consuming fewer calories than one expends.
   → Potential risks include nutrient deficiencies and a decrease in energy levels impacting training and recovery.
2. Low-carbohydrate diets: limits carb intake and increase protein and fat consumption
3. High-protein diet: for athletes aiming to increase muscle mass.

Question 24

State the approximate glycogen content of specific skeletal muscle fiber types (3)

Answer 24

slow twitch (type I) — low-glycogen content, since it mostly depends on aerobic metabolism

fast twitch (type IIa) — medium-glycogen content

fast twitch (type IIb) — high-glycogen content.

Question 25

Discuss the pattern of muscle glycogen use in skeletal muscle fiber types during exercise of various intensities (2)

Answer 25

Type I Fibers (slow-twitch): involved in endurance activities
→ Use small amounts of glycogen during sustained, moderate-intensity activities

Type II Fibers (Fast-Twitch): requiring quick, explosive movements
→ Rely heavily on glycogen for short, high-intensity bursts of activity.

Question 26

Describe, with reference to exercise intensity, typical athletic activities requiring high rates of muscle glycogen utilization (4)

Answer 26

SHORT DURATION, HIGH INTENSITY 🏋️‍♀️:
→ sprinting, weightlifting, gymnastics
→ glycogen is primary fuel, as they need rapid glycogen release
→ quicker depletion compared to lower-intensity exercise

LONG DURATION, MODERATE-HIGH INTENSITY:
→ marathon running, long distance cycling, triathlons
→ glycogen essential in the initial phase, and becomes vital as activity progresses

Question 27

State the reasons for adding sodium and carbohydrate to water for the endurance athlete (4)

Answer 27

SODIUM 🧂
1. Maintaining fluid balance: It helps regulate the body’s fluid balance.

2. Nerve and muscle function: Sodium is vital for muscle contraction (neuromuscular junction).

CARBOHYDRATE 🍔
1. Glycogen as a fuel source: The body stores carbohydrates as glycogen in muscles and liver, which are then converted to glucose for energy.

2. Continuous energy supply: During prolonged exercise, glycogen stores get depleted, carbohydrates are consumed to maintain blood glucose levels.

Question 28

Discuss the interaction of carbohydrate loading and training program modification ahead of competition (2)

Answer 28

NUTRITIONAL STRATEGIES 🍎:
→ Balance with food: Begin reducing training volume while progressively increasing carbohydrate intake. Prioritize carbohydrate loading to maximize glycogen stores.

TRAINING STRATEGIES 🏃‍♀️:
→ Gradual reduction of training intensity and volume before an event. Allowing the body to REST, ensuring glycogen stores are filled to maximum capacity.

Question 29

Discuss the use of nutritional ergogenic aids in sports (negative and positive) (12)

Answer 29

1. SPORTS DRINKS: rehydrating, replenishing electrolytes
   –> negative: excessive intake can lead to an imbalance in electrolyte levels and might have high sugar content.
2. ENERGY BARS: portable source of nutrients
   –> negative: some bars can be difficult to digest, and can have added sugars.
3. ENERGY GELS: concentrated, carbohydrate-rich gels
   –> negative: gastrointestinal discomfort and hydration need to absorb and digest.
4. CAFFEINE: improves focus
   –> varied responses to caffeine and excessive intake can lead to anxiety.
5. CREATINE: in sports that require bursts of high-intensity activity and aids faster recovery between intense training sessions.
   –> negative: may experience water retention and increased body weight.
6. BICARBONATE: buffering agent to neutralize lactic acid accumulation during high-intensity activities.
   –> negative: gastrointestinal discomfort.

Question 30

List of sources of protein for vegetarian and non-vegetarian athletes (2)

Answer 30

Non-vegetarian: meat (prime source), seafood, eggs.
Vegetarian: legumes, dairy, whole grains.

Question 31

State the daily recommended intake of protein for adult male and female non-athletes (2)

Answer 31

BOTH: 0.83 grams of body weight per day.
–> Age-Related Changes: Older women need increased protein to maintain muscle mass.

Question 32

Discuss the significance of strength and endurance training on the recommended protein intake for male and female athletes (4)

Answer 32

STRENGTH ATHLETES
–> Muscle Hypertrophy 💪: need more protein to support muscle growth and recovery.
–> Advised to consume about 1.6-2.2 grams of protein per kg of weight.

ENDURANCE ATHLETES
–> Maintaining muscle mass 🏊🏻‍♀️: require protein to preserve muscle mass and assist in recovery.
–> Recommended around 1.2-1.6 grams of protein per km of weight.

Question 33

Outline the possible harmful effects of excessive protein intake (7)

Answer 33

IMMEDIATE HEALTH CONCERNS 🏥
→ Digestive Discomfort: bloating, gas, constip.
→ Dehydration: greater water loss through urine

LONG-TERM HEALTH 👩🏻‍⚕️ IMPLICATIONS
→ Kidney Strain, potentially leading to long-term damage.
→ Can cause calcium loss from bones, increasing the risk of osteoporosis.

PSYCHOLOGICAL AND SOCIAL ASPECTS 👯‍♀️
→ Excessive attention on this risks disordered eating behaviors.
→ Social isolation and mental health challenges.

NUTRITIONAL 🍎 IMBALANCES
→ Insufficient consumption of other vital nutrients (vitamins, minerals, carbs, and fats).

Question 34

State the normal levels of blood glucose at rest

Answer 34

The human body normally keeps blood glucose level very stable (between 4.0 mmol/L–4.5 mmol/L)

Question 35

How are normal levels of blood glucose at rest maintained

Answer 35

Pre- and post-ingestion levels:
→ Fasting State 0️⃣: blood glucose levels are maintained through liver glycogenolysis.
→ Post, impact of Food Intake 🍔: consuming food, particularly carbohydrates, leads to a rise in blood glucose levels. The body responds by releasing insulin.

Pre- and post-exercise levels:
→ Anticipatory Rise 📈: slight increase in blood glucose levels before exercise, attributed to the body’s anticipatory response, which involves the release of glucagon and adrenaline.
→ Immediate Effects 📉: blood glucose levels dip due to glucose uptake by muscles for recovery of glycogen stores.

Question 36

Explain the transportation of glucose across the cell membrane when at rest and during physical activity (6)

Answer 36

Muscle fibers contain glucose transport proteins GLUT1 and GLUT4!!!
→ Glucose taken into the muscle cells is quickly converted to glucose-6-phosphate.

At Rest 🥱
→ Passive Transport: does not require energy.
→ Role of GLUT1: transporters ensure a steady supply of glucose.
→ Role of GLUT4: transporters stimulated by raised levels of insulin after eating.

During Physical Activity 🏃‍♀️
→ Increased Demand: require more glucose to meet the increased energy demands.
→ Role of GLUT4: GLUT4 transporters are mobilized to meet this increased demand, enhancing glucose uptake into muscle cells.

When are GLUT4 seen and used?
They are stored inside intracellular vesicles that are translocated to the cell membrane, when needed, to allow for greater glucose movement into the cell.

Question 37

Describe the acute effects of excess alcohol on the body (6)

Answer 37

💧Suppressing secretion of Antidiuretic Hormone, which normally signals water reabsorption.

✨ Kidney damage as they work more to filter and eliminate the high volume of urine.

🌡️ Thermoregulation: Alcohol interferes with the hypothalamus, can lead to improper body heat management.
In cold environments, → increases the risk of hypothermia.
In warmer settings, → overheating.

🫀Heart Rate and Blood Pressure increase (chemical control of H.R.)

🧠 Central Nervous System Effects: Alcohol acts as a depressant, imparing neuronal communication, leading to slowed thought processes and reaction times.

🏃‍♀️ Impairment in coordination and motor skills.

Question 38

Outline the possible effects of excessive chronic alcohol intake on body systems (9)

Answer 38

🩸Liver:
1. Alcoholic Liver Disease (ALD)
2. Fatty Liver: fat accumulates in liver cells.
3. Cirrhosis: irreversible liver scarring and impaired liver function.
4. Slows down metabolism

🫙Kidney:
ADH: Inhibits the release of the antidiuretic hormone, increasing urine output and risks of dehydration.

🫀Heart:
1. Hypertension: increasing the risk of stroke.
2. Cardiomyopathy: weakening and thinning of the heart muscles.

🧠 Brain:
1. Brain atrophy, particularly in the frontal lobe.
2. Mental Health Issues: depression, anxiety, and even psychosis.

Question 39

Discuss the effects of alcohol on athletic performance (10)

Answer 39

ERGOGENIC: performance-enhancing

1. TREMORS –> (low quant.) in precision sports (archery) can reduce hand tremors, thereby enhancing performance. Alcohol dampens anxiety and muscle tension.
2. CONFIDENCE ENHANCE –> temporarily boost an athlete’s confidence.
3. ANXIETY REDUCTION –> calming effect can lower performance anxiety.

ERGOLYTIC: performance-reducing

1. Balance and Coordination Impairment
2. Power and Strength Reduction, crucial for quick, explosive movements.
3. Alcohol accelerates fatigue.
4. Slowed REACTION TIME
5. Negative impact on decision-making in strategy-based sports.
6. Decreased cardiac function (H.B. pressure and arrhythmias).
7. Inhibition of Gluconeogenesis: interferes with the process of producing glucose from non-carbohydrate sources. This leads to lower energy levels, negatively impacting performance.

Question 40

Outline the role of antioxidants in the body

Answer 40

Molecules that can prevent or limit the damaging effects of free radicals by turning them into substances that are far less reactive.

→ Some nutrients such as vitamins A, C, and E
→ Ex. Berries, red grapes, kale, broccoli and tea

Question 41

Describe free radical production during exercise (4)

Answer 41

FREE RADICALS produced as a by-product of normal cell function
ANTIOXIDANTS counteract them.

→ Exhaustive exercise generates high levels of free radicals that cannot be controlled by natural antioxidants (oxidative stress).

→ Training partially reduces the build-up of free radicals as a result of exhaustive exercise.

Question 42

Explain the harmful effects of free radicals at the cellular level (4)

Answer 42

A free radical (reactive O2 species) is a particle that possesses at least one UNPAIRED electron.

These cause damage by removing electrons from parts of the cell in order to create paired electrons in their own structures.

Free radicals can:
→ remove electrons from cell and mitochondrial membranes, thereby affecting their permeability
→ remove electrons from molecules such as enzymes and DNA, thereby impairing their function.

Question 43

Evaluate the role of antioxidants for combating the effects of free radicals (4)

Answer 43

🍎 Antioxidants are found in many foods and so are consumed as part of a healthy, well-balanced diet.

🤼‍♀️ Many athletes consume antioxidants in dietary supplements as an extra defence against free radical damage.

📈 Excess intake may have detrimental effects on the body.

📑 There is no consistent evidence that these supplements reduce oxidative stress or have a positive impact on training or performance unless a pre-existing dietary deficiency exists.