Ok this should be a fairly easy one for the SDMB. What the hell is the difference between saturated fat and
non saturated fat? And how does it affect the body directly?
Saturated fats are saturated with hydrogen (every available valence elecron associated with carbon is bonded either to anothe carbon in the chain or hydrogen. Wait, I’m getting ahead of myself.
fats have a head and tails. The tails are carbon chains. A tail might look like this…
H H H H H
| | | | /
{base}=C-C=C-C=C-C=C-C=C
| | | | \
H H H H H
Note that each Carbon atom has four bonds.
Note that some of the carbons have double bonds connecting them. This fat is an unsaturated fat.
molecules can’t spin around double bonds, while they can around single bonds. The last two carbons in the chain can spin like a propeller on the end of the chain. (well, sort of) With the double bonds, however, this tail of the fat will be rather straight.
The above picture is over simplified; the tials are many many many carbons long.
When the chain is saturated with hydrogen, the double bonds break and bond with hydrogen.
H H H H H H H H H
| | | | | | | | |
{base}-C-C-C-C-C-C-C-C-C-H
| | | | | | | | |
H H H H H H H H H
The result is a long chain that can be twisted all around itself and knot itself around the other chains. This is a saturated fat.
If an unsaturated fat is made into a saturated fat, the process is called hydrogenation and produces a partially hydrogenated fat (or oil) or a hydrogenated fat (or oil). The idea here is that taking an unsaturated fat and hydrogenating it to make it thicker (creamy) is better than using a naturally saturated fat.
An example of this is peanut butter. If you smash up gobs of peanuts you get peanut butter. If you let it sit, the oil rises to the top. The oil is unsaturated. If you hydrogenate the oil to make it thicker (creamy) and add it back in, you get thicker peanut butter that does not separate. However, you don’t want it too thick to spread, so you only partially hydrogenate the oil. Read the back of your jar of SKIPPY.
One thing to note is that lots of saturated fat (no double bonds in Spritle’s picture) in the diet leads to a rise in your LDL cholesterol (the bad type). It is not self-evident why this should be the case (saturated fat and cholesterol are very different molecules).
In any case, this led to a recommendation to reduce the saturated fats in peoples diets and increase the polyunsaturated fats (many double bonds in Spritle’s picture). And sure enough, this leads to a reduction in peoples LDL cholesterol. Unfortunately, the good HDL cholesterol also drops.
It seems that substitution of so-called monounsaturated fats[sup]*[/sup], with one double bond, may be the best compromise. This tends to lead to a drop in LDL and a preserved level of HDL.
-
- found in things like canola oil, peanut oil, olive oil
Reading the whole thing is a bit tedious but the first part contains exactly the info you are after. A transcript of Alton Brown’s Good Eats program from FoodTV called Fry Hard.
NP: The Clash - London Calling
And then there’s essential fatty acids. Essential fatty acids (EFAs)regulate blood clotting, inflammation, and cholesterol. The long-chain Omega-3 fatty acids, the largest concentrations of which are found in fish, may lower the risk of heart disease and ease the pain of rheumatoid arthritis, by making blood less likely to coagulate and by suppressing a sequence of events that occurs between the cells of the immune system and those of the joints. (Health & Nutrition Letter, February 1999)
Polyunsaturated fatty acids are either “omega-3s” or “omega-6s.” Leafy greens and some vegetable oils (such as walnut, flaxseed, and canola) contain only the short-chain omega-3 linolenic acid, not the longer-chain fatty acids found in fish oils. Fish are able to convert the linolenic acid in algae and other sea plants into eicosapentenoic acid (EPA) and docosahexenoic acid (DHA). (U of Cal, Berkeley Wellness Letter, March 1999)
And then there’s trans fats. Spritle appears to be well-versed in chemistry. He’ll explain. I have to run now, anyway.