Lipids Flashcards
What is the % of fat in a lean healthy man vs severe obese
approx 16% compared to 70% mostly in adipocytes
What did the research of Ancel Keys find
High sat fat diet would increase serum cholesterol and lead to heart disease. The American Heart Assoc. then recommended a low fat high carb diet, substituting animal fats for seed oils. This led to into of statins.
Describe WHITE adipose fat and list functions
complex metabolically active endocrine tissue
- secretion of hormones
- growth factors
- enzymes
- protection of organs
- energy storage
- temperature insulation
Lipids exist in various forms, each with different structure and function. Name 4
- individual fatty acids
- triglycerides
- phospholipids (every cell membrane)
- cholesterol (steroid based compounds eg oestrogen)
- Sphingolipids (in nerve cell membranes eg myelin)
- Glycolipids (cell identity)
- cerebrosides (in brain)
- fat soluble vits (ADEK)
List as many function of lipids as you can (up to 10)
- Energy production (1g fat = 9 calories)
- storage of energy reserves (fats more efficient form of storage than carbs or proteins so excess stored as fat)
- cell membrane structure
- Thermal insulation (subcutaneous tissue around organs)
- steroid hormones (e.g. progesterone/oestrogen)
- formation of eicosanoids (signalling molecules involved in processes such as inflammation)
- Growth and development (brain rich in AA/DHA)
- Constitutes nervous tissue structure
- cell to cell signalling
- needed for absorption of ADEK
Describe the chemical structure of fatty acids
hydrocarbon chains with acid group at one end and methyl at other.
How many carbons does a short chain and medium chain fatty acids have, where do they travel to and what are they used for.
Which is useful to take before exercise
Short chain: 5 C
Medium chain: 6-12 Cs
Travel to liver used to create energy or ketones.
MCTs good source of energy before exercise (1tbs)
How many carbons does a long chain and very long chain fatty acid have and what are they used for
14-22 C and more than 22 Cs
Build cell membranes
How are SCFAs produced by the body
by dietary fibre fermenting in the COLON
Name the most common SCFAs
Acetate
Propionate
Butyrate
Which fatty acid is important for colon health and why
BUTYRATE
- supports intestinal tight junctions
- anti-inflammatory effect on the colon
How are fatty acids named
Using their common names and the omega nomenclature system
- Omega system: number of carbon atoms, number of double bonds, number of carbons from the omega end to the first carbon in the double bond.
How do unsaturated fats become saturated
with the addition of a hydrogen - hydrogenation, which turns the natural fatty acid into unnatural forms (trans)
Describe the composition of a saturated fatty acid (e.g. how many c-c double bonds)
no C-C double bonds. All carbons are completely saturated with hydrogen bonds.
Solid at room temperature
Describe the composition of unsaturated fatty acids
one or more double bonds between carbons. Liquid at room temp
Describe the composition of monounsaturated fatty acids
one double bond in the chain
Describe the composition of PUFAs
several double bonds in the
What is the result of an increasing number of double bonds in a fatty acid
the more double bonds the less stable and increasing susceptibility to oxidation
What do trans fats do to blood triglyceride and cholesterol profiles and what disease states are they linked to
alter blood triglyceride and cholesterol profiles - linked to CVD, insulin resistance and cancer.
Explain the configuration of a CIS fatty acid
H atoms are on the same side of the double bond
explain the configuration of a TRANS fat
H atoms are on separate sides of the double bond
are trans fats saturated or unsaturated
unsaturated but behave like saturated fats because of their unkinked shape
Name a natural trans fat
CLA - conjugated linoleic acid found in grass fed meat and dairy. Could increase lean muscle mass and decrease body fat.
Triglycerides: major form of dietary fat and storage form. Describe their structure
1 glycerol and three fatty acids.
The fatty acids can differ in length (number of C atoms) and degree of saturation (no. of hydrogen molecules attached)