Proteins: An In Depth Discussion

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Proteins An In Depth Discussion

• Presented by
• Professor Steven Dion Salem State College
• Sport, Fitness Leisure Studies Dept.

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Proteins

• Next to water its the most abundant substance in
  body.
• It aids in the transport of iron and oxygen to
  the body as well as
• aiding in the growth, maintenance and repair or
  all body tissues
• making of enzymes, hormones and antibodies,
• helps fight infection.

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Classification of Proteins / Amino Acids

• Peptides - link amino acids together to take on
  different forms
• Dipeptide - 2 joined amino acids
• Tripeptide - 3 joined amino acids
• Polypeptide - up to 100 amino acids
• Protein - combining more that 100 amino acids
  combined
• A single cell can contain thousands of different
  protein molecules. The body has over 50,000
  different protein-containing compounds.

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Other Purposes

• Blood plasma, visceral tissue, and muscle 3
  major sources of body protein.
• There is not storage of unused protein - all the
  protein in the body is being used for something -
  no true reservoir.
• Body protein makes up 12 - 15 if body mass -
  but the protein content of different cells
  varies. For example
• The brain cell consists of 10, a white blood
  cell and muscle cell have up to 20 protein.
• Skeletal muscle makes up about 65 of the bodies
  protein - but can increase with lifting.

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Amino Acids

• They are the building blocks for synthesizing
  tissues (approx. 20-22 amino acids)
• AAs activate vitamins key role in metabolic and
  physiologic functions.
• Anabolism tissue building process - accounts for
  1/3 of bodies intake of protein per day during
  rapid growth in infancy and childhood.
• As we slow down growing - so does the amount of
  protein the body sets aside for anabolism.
• Once you have reached full growth - there is a
  continual turnover of protein tissue.
• AAs / proteins make up the collagen which give
  structure to our hair, teeth, nails, skin, bones,
  and ligaments.

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Other Properties Roles

• Globular Proteins - make up over 2000 enzymes
  that speed up chemical reactions and regulate the
  catabolism (break down) of fats, carbs, and
  proteins for energy release. 
• Proteins assist in regulating acid-base quality
  of the body fluids -
• Buffering neutralizes excess acid metabolism
  formed during vigorous exercise.

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Amino Acids

• The body can not synthesize 8 amino acids (nine
  in children and some older adults)
• Those 8/9 are called essential amino acids so
  you need to get them from external nutrients.
• The 8 include isoleucine, leucine, lysine,
  methionine, phenylalanine, threonine, tryptophan
  and valine.
• Infants can not synthesize histidine and have
  difficulty with arginine.

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Amino Acids

• The body manufactures the remaining 9
• Those 9 are called nonessential amino acids.
• Nonessential means our body synthesizes them
  within the body, not that they are not important
• The source of the amino acids doesn't matter -
  just as long as the body gets the AAs whether
  its from plants or animals.
• Ideally coming from a nutrient rich, healthy food
  source.

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Proteins Major Categories

• Complete proteins or higher quality proteins -
  come from foods containing all of the essential
  amino acids in the quantity and correct ratio to
  maintain nitrogen balance and allow for tissue
  growth and repair.
• Incomplete proteins or lower quality proteins -
  lack ore or more of the essential amino acid.
  Incomplete protein diets will eventually lead to
  protein malnutrition. 

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Protein Sources

• Complete proteins sources include
• eggs, milk, meat, fish, and poultry. (pg. 31
  chart rating scale)
• Eggs provide the optimal mixture of essential
  AAs.
• Ideally choose egg whites and egg white protein
  shakes over whey/Casine powder shake.
• Complementary sources of incomplete / low quality
  proteins to create a complete protein meal
• You can combine incomplete proteins to create a
  complete protein meal.
• For example rice and beans, rice and lentils,
  tortillas and beans, and rice and peas

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Recommended Dietary Intake

• An intake greater than 3 times the recommended
  level does not enhance work capacity during
  intensive training. (so 12-15 of total cals)
• Excessive dietary protein becomes used for energy
  or recycled as components of other molecules
  including stored fat in subcutaneous (adipose)
  deposits.

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In Addition

• Consumption Consume .83 1 gram per kg.
• For example a 90 kg male should consume
  approximately 75 grams of protein per day.
• Infants and growing children should consume 2 4
  grams per kg.
• If you are pregnant Increase by 20 grams and if
  you are nursing increase by 10 grams.

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Protein Metabolism

• In well nourished individuals - protein breakdown
  contributes about 2-5 of the bodys total energy
  requirements.
• Catabolism protein breakdown
• 1. Body breaks nutrients into its amino acid
  components.
• 2. The amino acids go through the liver
  deanimation
• 3. Deanimation causes AAs to lose a nitrogen -
  creating urea (urine)
• 4. The new AA is free to produce carbs or fat or
  metabolize directly for energy.

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Key Terms

• Anabolism tissue building process
• Catabolism tissue breakdown process
• Deanimation the removal of the amino
  (nitrogen) from the amino acid thus creating
  urea.
• The remaining deaminated carbon compound can be
  used to form carbs or fat to produce energy.
• Excessive urea production requires increased
  fluid loss because urea must be diluted.

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Key Terms Continued

• Transamination the passing of nitrogen of an
  amino group form one compound to another
• Positive nitrogen balance nitrogen (protein)
  intake exceeds nitrogen excretion. (children,
  pregnancy illness)
• Negative nitrogen balance greater nitrogen
  output compared to intake. Energy has become a
  fuel source.(heavy exercises, fasting, starvation
  diets)

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Cautionary Note

• When catabolization occurs, ammonia is a
  byproduct of the process. This increases the
  amount of urea produced.
• High levels of urea production can lead to
  dehydration and calcium loss since urea needs to
  leave the body with water and it needs to be
  matched with calcium to do so. (Osteo what?)
• There is no advantage of consuming more protein -
  (except in times of growth and if you have poor /
  malnourished diet)
• These problems have been shown in individuals
  taking 3 - 4 grams per body wt.

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Info to Consider

• The type or amount of protein or proteins needed
  depends on your type of activity levels /
  exercises.
• A certain type of protein is made inside the
  muscle nuclei depending on its use - either
  aerobic or anaerobic protein synthesis.
• Athletes retain more protein and use more protein
  for energy sources than non-athletes. (pg. 337)

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Gender and Protein

• Naturally men have a higher metabolism than most
  women because of their larger physical size, bone
  structure, muscle mass larger brain size.
•  Women who have gone through menopause, may need
  to pay attention to protein intake and increase
  calcium to assist in the prevention of
  osteoporosis -

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Vegetarianism

• Vegan - no animal products
• Lacto-vegetarian - eats only dairy products -
  avoid all flesh products
• Ovo-vegetarian eats only eggs
• Ovolacto-vegetarian - eats eggs and dairy
• Pesco-vegetarian - eats fish, dairy, eggs, no red
  meat, poultry pork
• Semi-vegetarians - eat fish chicken, dairy, and
  eggs, but no red meat pork

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Benefits of the Vegetarian Diet

• Lowers LDL cholesterol levels without having an
  effect on HDL levels
• Typically less fat and healthier body
• Less possible toxins in food
• Reduced risk of colon, heart, breast cancer

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Drawbacks of a Vegetarian Diet

• Difficult to have a lot of variety - more
  difficult to prepare yummy foods dishes
• Can be expensive
• In the US less education on creative and healthy
  cooking
• Lack of knowledge can lead to deficiencies
• Possible deficiencies in B2 (riboflavin) and B12,
  and D. B2 is found in meats and eggs, dairy - but
  broccoli, almonds, asparagus
• B12 and D are found only in dairy products but
  B12 is made by body and D can be synthesized with
  sunlight, or soy milk.