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					Fish and NUTRITIONAL
      contribution


      Wk 2 Lect 4
Re-cap
• Fish stock is declining
  – The depletion of large mature fish
  – Pollution,
  – Fishing techniques
  – Climate changes

• Despite decline in fish production
  – there is an increase in fish consumption
     • Both direct and indirect human consumption

  – 180kcal obtained from fish
Learning objectives
• Discuss and examine nutritional significance
 of seafood
  – Protein
  – Polyunsaturated essential fatty acid
     • Omega 3
  – Vitamins
  – Minerals
  – Antioxidants
• Discuss and examine health benefits
Nutrient compositions
• Fish and shellfish are more tender than other flesh foods

• Nutrient compositions of fish include;
   – High proteins; AA -EAA
       • Highly digestible
       • 17 to 25% protein (average = 19 g/100 g)

   – Fats (polyunsaturated: ε-3 unsaturated) (depends on types of
     fish)
       • finfish and shellfish are low in fat, less than 5%, or most- less than
         1% fat
   – Carbohydrates: glycogen (small quantity)
   – Vitamins – fat soluble A & D and (B; niacin, B12 and B6).
   – Minerals (I, Ca, p (phosphorus) and se
    Health advantage of fish
• High digestible protein
     – Essential Amino Acids
         • Arginine, histidine, isoleucine, leucine, lysine, methionine, plenylalanine,
            threonine, tryptophan and valine
•   Low calorie
•   Low saturated fat
•   High in polyunsaturated
•   EFA
•   ω-3 unsaturated FA (ability to reduce HDL)
     – Fish liver oil
• Fat soluble vits; A & D, Bs; B1, B2, niacin, B6 and B12
• Minerals I, Ca (small fish e.g. sardines and canned varieties such
    as salmon, tuna, mackerel)


     – Increasing the intake of fish is associated with low calorie and saturated
       fatty acid intake
Functional properties of major
nutrients
• Proteins and enzymes
  –   Build and growth (muscles and other tissues)
  –   Reproduction
  –   Maintenance
  –   Repair

• Polyunsaturated fats
  – Provides energy and helps fat soluble vitamins to be
    absorbed
     • A and D
  – Essential fatty acids promote health
Other important nutritional info
• Minerals in seafood include;
     • Zinc (oysters and crustaceans),
     • Iron (oysters, bluefish, and shrimp),
     • copper (oysters, crabs, and lobster),
     • potassium (mussels, scallops, clams),
     • Iodine, phosphorus, and selenium (all seafood
       in general).
     • Iodine is present in seaweeds

  – Fresh seafood is low in sodium compared to its
    processed counterparts such as smoked,
    cured, and most canned seafoods.
     • Salt is added in the processing for preservation.
• CHOLESTEROL
  – Finfish are generally quite low in cholesterol of ~ 50-90 mg cholesterol per
    100g (3-1/2 ounces).

  – Shellfish (molluscan) having low to moderate amounts of ~ 40-110
    mg/85 gms.
      • However, high in the fish roe

  – Molluscs, such as clams, oysters, scallops, and mussels were found to have
    a large percentage of non-cholesterol sterols
      • Which inhibit the absorption of cholesterol eaten at the same meal.

  – Cholesterol levels in crustaceans as crab and lobster are quite similar to
    that found in the dark meat of chicken
      • Crustaceans (crab, lobsters, shrimp) contains 60- 100 mg/85 gms

  – Squid and octopus may contain relatively high levels, 250 and 122
    mg/85gms, respectively.

  – Cholesterol in shrimp varies considerably by species
      • Generally 1-1/2 to 2 times higher than in the dark meat of chicken, but far less
        than in eggs.
• Fish oils (fat)
   – provides a protective effect in minimizing the
     development of chronic degenerative diseases,
     therapeutic effect in cases such as arthritis


   – fish oils are composed primarily of the omega-3 fatty
     acids.
       • They differ from most plant oils which contains mainly the
        omega-6 fatty acids.


   – most important omega-3 fatty acids found in seafood
     are
      • eicosapentaenoic acid (EPA)
      • docosahexaenoic acid (DHA).
• Primary producers of omega-3 fatty
 acids
  – algae and phytoplankton
     • Fish and shellfish ingest and accumulate omega-3
      fatty acids through the food chain
• How omega-3 fatty acids prevent or improve
  human diseases?

  – Omega-3 fatty acids help keep our bodies from over-
    production of eicosanoids;
     • a group of hormone-like substances that can, in large
       amounts, contribute to arthritis, asthma, heart disease,
       stroke, and related disorders.

  – The eicosanoids are normally derived from
     • the omega-6 PUFA arachidonate, found predominantly in
       plant oil.


  – Omega-3 fatty acids act as an antagonist to eicosanoid
    synthesis, thereby lowering their production.
     • lowers serum cholesterol levels.
     • also forms modified eicosanoids less active than the normal
       compounds.
• Omega-3 fatty acids
  – change the critical balance of certain blood components
    called lipoproteins,
     • thus reducing the
          – low-density lipoproteins (LDL)
          – and very low density lipoproteins (VLDL) that deposit cholesterol
            along the artery walls.


  – lower the levels of triglycerides,
      • another type of fat involved in heart disease.

  – form a different pattern of prostaglandin,
     • diminishing the clotting of blood cells,
     • reducing the number and stickiness of blood platelets,
     • making red blood cells more flexible so that they flow more
        smoothly.
• Other health problems that may be
 controlled or alleviated by the
 consumption of omega-3 fatty acids

  – asthma, arthritis, diabetes, multiple sclerosis,
    hypertension, migraine headaches, cancer,
    and some kidney diseases.
Fish rich in omega-3
Frequency of seafood to be consumed

   – Man can only produce saturated and omega-9
     fatty acids, which means we need omega-3
     fatty acids through diets.


   – Have seafood dishes once or twice a week
     has been recommended in preventing
     coronary heart disease.
Conclusion

• Seafood is an essential food containing
 essential nutrients that promote health

  – Especially in the Pacific, it should be the core
    component of our diet

				
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