1.3 Lipids Flashcards
Solubility
Insoluble in water
Two forms:
Fats are solid at room temperature
Oils are liquid at room temperature
Provide how much kJ?
37kJ/g
Functions
Store energy as triglycerides (fuel reserve)
Insulation and protection
Control metabolism
Provide satiety
Triglycerides
3 fatty acids + glycerol
Composed of C,H,O
Phospholipids functions
Emulsifiers
Sources: egg yolk, soybeans
Saturated
Every carbon (C) atom has its full quota of Hydrogen (H) atoms
Best to be kept to a minimum in the diet
Hard at room temperature
Usually derived from animal sources
Unsaturated
Carbon (C) contain less than their full quota of Hydrogen (H) atoms
Results in formation of one or more double bonds
Mono-unsaturated
Only one double bond between C atoms
Polly-unsaturated
Two or more double bonds between C atoms
Saturation
Affects the temp at which fats melt
More saturated = more liquid y
Omega-3 Functions
Reducing the chances of blood clots (thrombosis)
Counteracting irregular heart beat (cardiac arrhythmia)
Lowering triglyceride levels (blood fat that is as potentially dangerous as cholesterol)
Help brain growth and function
Omega-6
The regulation of…
- Blood pressure
- Blood clot formation
- Immune response
Food sources:
sunflower and safflower oils – linoleic acids
vegetable oils and meat – arachidonic acids
Trans Fats
^ LDL / decrease HDL
Cholesterol
Made in liver and intestines
Not readily absorbed
Very-low-density lipoproteins (VLDL)
Deliver triglycerides to cells
Low-density lipoproteins (LDL)
Larger particles that deposit cholesterol on the inside of walls in the arteries.
High-density lipoproteins (HDL)
Smaller particles and protect against heart disease as they pick up cholesterol to the liver for removal or recycling.
Lower Cholesterol
Reduced fat milk
Use mono or poly spreads rather than butter
Choose lean meat / trim fat / remove skin
Eat oily fish
Lipid Digestion
Mouth and Stomach - Minimal digestion of triglycerides
Small intestine:
- Bile emulsifies fat
- Digested by pancreatic lipase
- Fats are spilt into smaller particles: 3 fatty acids and glycerol for absorption
- Absorbed into intestinal cells
Deficiency or Excessive
Deficiency: (Rare in Australia)
Eczema
Skin lesions
Failure to grow
Excess:
Stored as adipose tissue -> Weight gain -> obesity
- Hypertension,
Atherosclerosis, Heart Disease, Stroke and Type II Diabetes.
