Download Fats

Fats
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one important of macronutrient .
each one gm of fat yield 9 kcal of energy .
importance of fat :
1-source of energy & storage .
2-essential nutrient supply .
3-food satiety [ feeling of taste ,& add flavor to food
, slow gastric emptying .
 Function of Fat :
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1-energy production .
2-thermal insulation .
3-vital organ protection .
4-nerve impulse transmission .
5-enter in cell membrane structure & help in
transportation of nutrient cross the cell membrane .
 6-enter in cell metabolism { lipo protein carry fat in
the blood to all cells }.
 7-essential precursor substance{ fatty acid &
cholesterol }.
 N B : too much of fat store in adipose tissue lead to
increase body WT hypertension ,heart disease
,diabetes mellitus .
*physical characteristic of fat : greasy in touch
,insoluble in water .
*types of fat :
1- saturated fat : comes from animal origin ,fatty acid
saturated with hydrogen .
2- monosaturated fat : comes from plant origin as olive
oil ,fatty acid saturated with one hydrogen ion .
3- poly saturated fat : fatty acid is saturated with two
or more of hydrogen ion ,comes from plant source as
coconut oil, palm oil .
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*essential fatty acid : the body cant manufacture it &
therefore must obtain it from the diet .
-function :
@ membrane structure { strength the cell membrane }.
@cholesterol transport to blood .
@has role in blood clotting prolonged of clotting time
@ local hormone like effect { prostaglandin
,prostacycline thromboxane ,& leukotriens .
Prostaglandins :
- 1stly discovered in the semen which comes from
prostatic gland .
- Has role in smooth mulched tone & platelet
aggregation .
- Derived from fatty acid
- Hormone like action ,regulation of gastric acid
secretion.
- Has role in inflammatory process & body temp.
control .
- Lower of Bp .
*Triglycerides:
Three fatty acid chains attached with glycerol ,[
monoglycerids ,diglycerids ,triglycerides ].
- saturated fatty acid comes from animal source as
milk , meat ,eggs .
- unsaturated fat comes from plant source as
vegetable oils .
 visible & hidden food fat :
visible butter, margarine ,oil salad dressing ,bacon &
cream .
- hidden fat : egg yolk is fat , white is pure protein ,
also nuts seeds , olives ,avocadoes .
*cholesterol :
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Run in blood stream , consider vital structure in human
metabolism , origin from steroid .
- essential in formation of bile .
- enter in enzymatic digestion of fat .
- found in large amount in the brain &nerve tissue .
- essential component of cell membrane .
- cholesterol has role in cardio vascular disease {
atherosclerosis }.
 NB:
Lipoprotein is a mixture of lipid & protein .
-HDL: high density lipoprotein .
-LDL: low density lipo protein .
* digestion of fat:
-in the mouth fat break down into small particles by
chewing & mastication .
-in the stomach mechanical mixing of fat with gastric
secretion .
- in the small intestine , bile secretion & pancreatic
enzyme , with small intestine secretion digest fat .
- because fat is not water soluble unite with protein to
form lipo protein go to lymphatic system for
absorption .
- metabolism : burn out of fat to produce energy .
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