1. FATTY ACIDS

5. Fatty Acids ……… DEFINITION
Fatty acid: a long, unbranched chain carboxylic acid, most commonly of carbons, derived from hydrolysis of animal fats, vegetable oils, or phosphodiacylglycerols of biological membranes.
Denovo synthesis occurs from acetyl coA (lipogenesis)

7. Fatty acids differ from one another in:
Fatty acids - are components of triacylglycerols, glycerophospholipids, sphingolipids
Fatty acids differ from one another in:
(1) Length of the hydrocarbon tails
(2) Degree of unsaturation (double bond)
(3) Position of the double bonds in the chain
Prentice Hall c2002
Chapter 9
Fig 9.2

8. Omega-3, omega-6 and omega-9
Long Chain Fatty Acids are typically even numbered
SATURATED no C-C double bonds
UNSATURATED - at least one C-C double bond
Monounsaturated - only one C-C double bond
Polyunsaturated - two or more C-C double bonds
Omega-3, omega-6 and omega-9

10. Fig. 9.3 Structures of three C18 fatty acids
(a) Stearate (octadecanoate)
(b) Oleate (cis-D9-octadecenoate)
(c) Linolenate (all-cis-D9,12,15-octadecatrienoate)
The cis double bonds produce kinks in the tails of unsaturated fatty acids
Prentice Hall c2002
Chapter 9

11. Fatty Acids

12. Fatty Acids Among the fatty acids most abundant in plants and animals
nearly all have an even number of carbon atoms, most between 12 and 20, in an unbranched chain
the three most abundant are palmitic (16:0), stearic acid (18:0), and oleic acid (18:1)
in most unsaturated fatty acids, the cis isomer predominates; the trans isomer is rare
unsaturated fatty acids have lower melting points than their saturated counterparts; the greater the degree of unsaturation, the lower the melting point

13. Difference between Cis & Trans
If the acyl chains are on the same side of the bond, it is cis-, example: oleic acid.
if on opposite sides, it is trans-,  example: elaidic acid, the trans  isomer of oleic acid

14. Double bonds in naturally occurring unsaturated long-chain fatty acids are nearly all in the cis  configuration, the molecules being "bent" 120 degrees at the double bond. Thus, oleic acid has an L shape, whereas elaidic acid remains "straight.“

15. Clinical Significance
Consumption of trans fatty acids  not good for health.
Previously in Margarine  Higher number of Trans FA.
Now soft margarine low in trans fatty acids or containing none at all.

16. Hydrogenation Plant Hydrogenation involves: Heating oil
Pressurizing oil
hydrogen gas
Using platinum catalyst
Trans fats are a by
product of hydrogenation
0 g trans fats does not
mean zero
It means <0.5 g per serving!

21. How Can Fatty Acids Modulate the Immune System?
Why do we need immune modulation in the first place?
Answer: Similar to avoid excessive, chronic inflammation which leads to tissue destruction.
FAs such as DHA and EPA can reduce production of inflammatory cytokines (IL-6, IL-12, IL-23)
FAs can increase phagocytic activity
FAs can decrease lymphocytic proliferation
FAs can influence immune cell migration