1. Fats

2. 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 .

3. Function of Fat : 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 }.

4. 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

5. *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 .

6. *essential fatty acid : the body cant manufacture it & therefore must obtain it from the diet .

7. -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 .

8. 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 .

9. *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 .

10. 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 .

11. *cholesterol :
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 }.

13. NB: Lipoprotein is a mixture of lipid & protein .
-HDL: high density lipoprotein .
-LDL: low density lipo protein .

14. 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 .