Nutrition and Exercise

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Nutrition and Exercise

• Carbohydrates.
• Lipids.
• Protein.
• Vitamins, minerals and water.
• Diet and exercise.
• Drugs in sport.

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You are what you eat
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Food means health
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Types of food

• Carbohydrate, lipid, protein.
• Biologic fuel.
• macronutrients to maintain body structure and
  functional integrity.

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Carbohydrates

• Mono-, oligo- and polysaccharides.
• Differ by number of simple sugars linked within
  the molecule.
• Basic unit is monosaccharide, with gt 200 forms in
  nature.

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Monosaccharides

• Glucose (dextrose or blood sugar), is produced
  through digestion of more complex carbohydrates.
• Fructose (fruit sugar) is the sweetest simple
  sugar.
• Galatose is not found in nature, it is combined
  in milk sugar.

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Oligosaccharides

• Sucrose (cane sugar) is the most common dietary
  disaccharide.
• Lactose (milk sugar) is composed of glucose and
  galatose in milk.
• Maltose (malt sugar) does not form significant
  component of a normal persons diet.

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Polysaccharides

• Starch and fiber are common plant
  polysaccharides.
• Starch - the storage form of carbohydrate in
  plants.
• Fiber - nonstarch polysaccharide such as
  cellulose.
• High water content in fiber - bulk to food
  residues in small intestine.

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Polysaccharides

• Glycogen - storage carbohydrate to mamalian
  muscle and liver.
• Converted to glucose when needed.
• If depleted, glucose synthesis from other
  nutrients, principally protein.
• Upper limit of glycogen storage is 15 gm/kg.

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Function of carbohydrates

• Serve as fuel, particularly during exercise.
• Spare protein break down.
• Primer for lipid metabolism.
• Essential for CNS functioning.

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Carbohydrate (CHO) deficiency

• Dietary restriction of CHO rapidly depletes liver
  and muscle glycogen.
• Adversely affects intense short-term and
  prolonged submaximal exercises.

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Lipids

• Long hydrocarbon chains.
• Simple, compound and derived lipids.
• Triglycerides are the most plentiful lipids in
  the body.
• A cluster of glycerol with 3 clusters of fatty
  acids.

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Lipids

• Saturated and unsaturated fatty acids (FA).
• Saturated FA contains no double bonds between
  carbon atoms.
• Unsaturated FA contains at least one double bond
  between carbon atoms.

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Lipids

• 62 of FA in butter are saturated.
• Only 20 of FA in margarine are saturated.
• Margarine also increases LDL cholesterol and
  decreases HDL cholesterol concentration.

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Compound lipids

• Triglyceride in combination with other chemicals.
• Phospholipids, glycolipids, lipoproteins.
• Lipoproteins constitute the main form for lipid
  transport in the blood.
• HDL, LDL and VLDL.

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Derived lipids

• Derived from simple and compound lipids.
• Cholesterol is a derived lipid.
• Even on a cholesterol free diet, the body
  synthesizes 0.5 to 2 g of cholesterol per day.
• Cholesterol is needed for plasma membranes,
  synthesis of vitamin D, some hormones and bile.

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Lipids

• For better health, lipid intake should be lt 30
  of the total energy content of the diet.
• Among the lipid intake, at least 70 should be in
  the form of unsaturated FA.

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Role of lipids

• Largest energy pool of the body (75 times that of
  CHO).
• Cushioning of organs.
• Insulator for thermal fluctuation.
• Carrier and transport medium for Vitamin A, D, E
  and K.

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Proteins

• Greek word meaning of prime importance.
• The body requires 20 amino acids (AA) for protein
  synthesis.
• 8 AAs cannot be synthesized by the body, which
  are the essential AAs.

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Proteins

• A daily intake of 0.83 g/kg body mass is
  recommended.
• Infants should take 2 to 4 g/kg, and pregnant
  women should take 20 g/kg of body mass.

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AA supplement

• AA supplement above the recommended intake does
  not increase muscle mass or improve muscular
  strength, power or endurance.
• Could adversely load the liver and kidney.

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Nitrogen balance

• If ve N balance, N intake gt excretion, protein
  will be retained and new tissues will be
  synthesized.
• Exercise would lead to protein break down
  particularly when CHO is depleted.

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Vitamins

• Organic substances needed by body in small
  amount.
• No energy value.
• At least 13 vitamins, and only vitamin D can be
  manufactured by the body.
• Vitamin C is a strong antioxidant.

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Vitamins

• If little is good, more must be better?
• Vitamin supplement has not been shown to improve
  exercise performance for people with adequate
  nutritional intake.
• Lipid-soluble vitamins (A,D,E,K) should not be
  consumed in excess.

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Minerals

• Approximately 4 of the bodys mass is composed
  of minerals.
• Major vs. trace minerals.
• Provide structure (bones).
• Function (muscle and nerve).
• Regulate cellular metabolism (enzyme).

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Minerals

• Ca and P constitute 2.5 of body mass.
• Fall in estrogen at menopause decreases
  calcitonin, which is needed for Ca absorption.

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Minerals

• Mg is present in about 300 enzymes.
• Iron is present in 80 as its active compound
  haemoglobin.
• Na, K and Cl- are termed electrolytes because
  they exist in charged forms.
• Electrolytes maintain electrical gradient across
  cell membrane.

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Water

• Most remarkable nutrient.
• Serves as the bodys transport and reactive
  medium.
• Important for heat regulation.
• Without water, death occurs within days.

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Water

• About 2.5 L of water is needed each day for a
  sedentary person.
• 15 mL of water is needed to remove 1 g of solute.
• Hyponatremia is associated with excessive fluid
  intake and insufficient Na.

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An optimal diet is a diet that contains all the
nutrients needed for tissue maintenance, repair,
and growth without excess energy intake.
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Nutrient requirement

• Young adult females 2100 kcal.
• Young adult males 2700 kcal.
• CHO is most rapidly depleted.
• After exhaustive exercise, at least 1 or 2 days
  rest with high CHO intake is needed to replenish
  the glycogen level.

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Exercise meal 1

• Fasting before exercise makes no physiological
  sense.
• A meal containing 150-300 g CHO consumed 3-4
  hours before exercise improves performance by
  maximising muscle and liver glycogen storage.

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Exercise meal 2

• CHO consumption during exercise benefits both
  intense and endurance types of work.
• Too much CHO immediately before exercise is
  detrimental to performance.
• Ideal rehydration solution contains CHO
  concentration between 5-8 .

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Drugs in sport 1

• Belief of competitors are using drugs.
• Overriding desire to win.
• Pressure from authority or peers.
• Deprived legitimate resources.
• Ignorance.

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Drugs in sport 2

• The Olympic Movement Anti-Doping Code.
• Prohibited substances
• stimulants, nacrotics, anabolic agents,
  diuretics, peptide hormones.
• Prohibited methods
• blood doping, artificial O2 carriers,
  pharmacological or chemical/physical manipulation.