TOPIC  4:NUTRITION  part  1  

Learning  outcomes  

1.  Iden4fy  the  func4ons  of  nutrients.  2.  Compare  intracellular  and  extracellular  

diges4on.  

3.  Describe  the  func4on  of  diges4ve  systems  in  animals.  

4.  Iden4fy  the  needs  of  nutri4on  in  plants.  5.  Describe  the  transporta4on  of  water  and  

nutrients  in  plants.  

Part  1  Content  

1.  Nutri4on  2.  Classes  of  nutri4on  3.  Introduc4on  to  nutri4on  

1.  Carbohydrate  2.  Lipids  3.  Protein  4.  Minerals  5.  Vitamins  

4.  Intracellular  diges4on  5.  Extracellular  diges4on  

Nutri0on  

•  A  nutrient  is  a  component  of  food  that  is  needed  for  a  specific  physiological  func4on.  

•  All  aspects  of  bodily  func4on  depend  upon  proper  nutri4on.  

•    Deficiency  disorders  occur  when  the  body  lacks  a  nutrient  required  for  a  func4on.          

The  Classes  of  Nutrient  •  There  are  six  classes  of  essen4al  nutrient.  

1.   Carbohydrates  2.   Lipids  3.   Proteins  and  amino  acids  4.   Minerals  5.   Vitamins  6.   Water  

•  A  balanced  diet  contains  all  the  6  classes  of  nutrient  which  includes  fibers  

•  These  nutrients  may  be  needed  in  large  amounts  (macronutrients)  or  small  amounts  (micronutrients).  

Introducing  the  Nutrients    

CLASS   ROLE   Macro  or  micro?  

Carbohydrates   Energy,  fiber   Macronutrient  

Lipids   Energy,  insula4on,  vitamin  D  synthesis  

Macronutrient  

Proteins   Provides  essen4al  amino  acids   Macronutrient  

Minerals   Homeostasis,  water  balance,  cofactors  

Micronutrient  

Vitamins   Metabolism  and  development   Micronutrient  

Water   Hydra4on,  temperature  control   -­‐  

CARBOHYDRATE  

Carbohydrates  •    Carbohydrates  include  sugars,  starches  and  fiber.  •  Sugars  can  be  present  as  monosaccharides  such  as  glucose  or  

disaccharides  such  as  sucrose.  •  Glucose  is  metabolized  for  energy    

•  Starch  is  complex  carbohydrates  stored  by  plants  

•  Fibers-­‐  preven4ng  cons4pa4on  

Fiber  (Cellulose)  

•    Fiber  or  cellulose  is  the  indiges4ble  carbohydrates  derived  from  plant  material.      

•  Fiber  is  not  considered  a  nutrient  for  human  because  it  cannot  be  digested  to  smaller  molecules  in  human  diges4ve  system.  

•    Insoluble  fiber  is  important  because  it  s4mulates  movement  of  feces  in  the  bowel.  

•    Soluble  fiber  binds  to  compounds  in  the  intes4ne  to  deter  their  absorp4on  and  enhance  their  excre4on.      

Can  Carbohydrates  Be  Harmful?  

•  Carbohydrates  are  important  because  they  provide  about  45%  of  the  body’s  energy  needs.  

•  In  our  diet,  about  1  g  of  carbohydrates  provide  4  calories  of  energy  (compared  to  1  g  of  fat  ~  9  calories)  

•  Excess  carbohydrates  in  the  diet  can  contribute  to  obesity,  diabetes,  and  other  diseases.  

A  low-­‐GI  food  will  release  glucose  more  slowly  and  steadily,  which  leads  to  more  suitable  postprandial  (a[er  meal)  blood  glucose  readings.  A  high-­‐GI  food  causes  a  more  rapid  rise  in  blood  glucose  levels  and  is  suitable  for  energy  recovery  a[er  exercise  or  for  a  person  experiencing  hypoglycemia.  

LIPID  

Lipids  •  There  are  different  forms  of  lipids  

that  influence  nutri4on.  

•  Lipid  (3  fa^y  acids  +  glycerol)  called  triglyceride  

•  Triglycerides:  

–  such  as  fats  and  oils  supply  cells  with  energy.  

–  Fat  is  a  long-­‐term  storage  form  for  lipids.  

–  necessary  for  nutri4on.  –  fats  and  oils  should  provide  

30-­‐35%  of  the  body’s  energy.  –  contain  essen4al  fa^y  acids  

that  the  body  requires  for  proper  func4on.      

Can  Lipids  Be  Harmful?  •    Cholesterol  is  a  lipid  that  

serves  an  important  func4on  in  cells..e.g.  to  make  certain  hormones,  bile  &  vitamin  b.  

•  However,  elevated  levels  of  cholesterol  and  fats  in  the  blood  can  be  detrimental  to  health.  

•  Lipids  should  not  be  eliminated  from  the  diet,  but  should  be  consumed  in  modera4on  from  more  nutri4onal  sources.  

PROTEIN  

Proteins  

•    Proteins  consumed  in  the  diet  are  broken  down  to  liberate  amino  acids,  nine  of  which  are  essen4al  in  the  diet.  

•  While  all  foods  contain  protein,  plant  proteins  are  considered  “incomplete”  because  they  generally  lack  one  or  more  of  the  essen4al  amino  acids.  

•  This  limita4on  can  be  overcome  by  ea4ng  specific  combina4ons  of  plant  foods.      

Can  Proteins  Be  Harmful?  

•  Proteins  should  supply  no  more  than  10-­‐15%  of  the  calories  consumed  in  the  diet.  

•  Excess  protein  in  the  diet  cannot  be  used  produc4vely  and  is  generally  excreted  as  urea  in  the  urine.      

•  High  protein  diets  can  lead  to  some  health  problems,  such  as  dehydra4on,  calcium  loss,  and  kidney  stones.    

MINERALS  

Minerals  

•  The  term  minerals  is  applied  to  the  20  elements  that  are  required  for  nutri4on.  

•  Mineral  are  necessary  for  regulate  energy  metabolism,  maintain  fluid  balance,  produce  certain  structure,  enzymes  &  hormones.  

•     •  Absence  of  a  specific  mineral  can  

lead  to  mineral  deficiencies.  –  Low  iron  can  lead  to  anemia.  –  Low  calcium  can  lead  to  

osteoporosis.  

•  Excess  minerals  in  the  diet,  such  as  sodium,  can  also  have  harmful  effects.  

Minerals  (cont.)  

Major minerals Primary Functions

Calcium Strengthen bones, nerve function

Phosphorus Bone growth, energy metabolism

Potassium Nerve function, muscle contraction

Sodium Nerve function, pH and water balance

Magnesium Nerve and muscle function

Chloride Water balance

Minerals  (cont.)  

Trace minerals Primary Functions

Zinc Protein synthesis, immune function

Iron Hemoglobin synthesis

Copper Hemoglobin synthesis

Iodine Thyroid hormone synthesis

Selenium Antioxidant

Vitamins  •    Vitamins  are  essential  organic  compounds  other  than  carbohydrates,  lipids,  and  proteins  that  regulate  metabolic  activities.  

•  Vitamins  contribute  primarily  to  energy  metabolism  and  antioxidant  defenses.      

•  Vitamin  deficiencies  can  lead  to  serious  disease.  

Vitamins  (cont.)  

Water-soluble vitamin Primary functions

Vitamin C Antioxidant, maintains capillaries, bones, & teeth

Thiamine (B12) Important coenzyme, activity of nervous system

Riboflavin (B2) Coenzyme for energy, fat, & protein metabolism

Niacin Coenzyme for energy, fat, & protein metabolism

Vitamins  (cont.)  

Water-soluble vitamin Primary functions

Folic acid Helps form hemoglobin

Vitamin B6 Helps form hemoglobin

Pantothenic acid Coenzyme for fat & carbohydrate metabolism

Vitamin B12 Coenzyme for DNA synthesis

Biotin Coenzyme for amino acid and fatty acid metabolism

Vitamins  (cont.)  Fat-soluble vitamin Primary functions

Vitamin D Bone and teeth development

Vitamin E Antioxidant

Vitamin K Synthesis of clotting factors

Intracelullar  &  Extracelullar  Diges0on  

                       Diges0on  

Intracellular Digestion

Extracellular Digestion

Single opening Two openings

Intracellular  Diges0on  

•  referring  to  hydrolysis  of  food  inside  vacuoles  in  a  single  cell.  

•  Examples  of  intracellular  diges4on:  

 i)process  of  phagocytosis  (engulf  solid        

             food)    

 ii)  process  of  pinocytosis  (liquid  food).  

Extracellular  Diges0on  (single  opening)  

•  Simple   organism   having   single   pouch  (gastrovascular   cavity)   with   single  opening.  

•  Examples:      -­‐Cnidarian  (hydra  form)  

 -­‐Flatworm  

Extracellular  Diges0on  (two  openings)  

•  Common  in  most  animals.  •  The   diges4ve   tube   having   two   openings   at  each  end  (mouth  and  anus).  

•  Also   known   as   complete   diges-ve   tract   or  alimentary  canal.  

END  OF  PART  1