Chemically, why are unsaturated fats healthier than saturated fats?

Question

Sturated fats are formed by a carboxyl head attached to a string of carbons. If all of the carbons are bound by two hydrogens (3 on the tip), it is considered to be saturated. Saturated = completely filled. If there is at least 1 double bond between two carbons, the shape of the chain changes, and since there are now two carbons not bonded to two hydrogens, it is no longetr saturated w/ hydrogens-- it is unsaturated. Double bonds are harder to break that single bonds. Why is it then that unsturated and polyunsaturated fats are healithier, even though they contain bonds that are harder to break? Shouldn't the saturated fats be easier to break apart?

Answer 1

The thing is that a cis touble bond (the kind where the two carbons are on the same side of the bond) creates a sort of a kink in the carbon chain. In saturated fats, there are no double bonds, so the carbon chain is more or less a straight line, but in unsaturated fats, the carbon chain is bent in one or more location. The straight molecules of the saturated fat can pile up into stacks with all the molecules lined up parallel to each other. Unsaturated fats, on the other hand, can't do this. Think about a bendy straw. In the box, they can be packed together into a tight solid, but as soon as you bend the part at the top they can't be packed together nearly as neatly or closely.

Saturated fats are less healthy not because they can't be broken down as easily, but because they are better able to form a tightly packed solids, so they tend to have higher melting points, and are therefore more likely to form solid masses in your arteries and elsewhere. Unsaturated fats tend to be liquids, so they don't clog things up as much.

Incidentally, in trans fats, the carbon atoms around the double bond are arranged across from each other so that the carbon chain is straight, like in saturated fats, so they behave similarly to saturated fats, which is why they are so much worse for you than naturally occuring unsaturated fats.

Answer 2

It comes down to their melting points. Since saturated fats have more atoms attached they take a higher temp to turn them into a liquid. The more unsaturated a fat is, the lower the temp it can be found a liquid. With the body at a constant temp, having something solid in the blood stream causes serious problems.

Answer 3

Interesting question. I'd like to provide yet another view to this as many of the answer provided before me were good. But, as you probably already know, chemistry is full of models to examine a variety of problems as well as provide many answers (eg many points of view) to the same question. So, another point here is those elusive electrons in the double bonds. They are available for true chemical reactions (melting point, structural confermations, etc. are physical "reactions"). The problem here with double bonds from a health point of view is that the body is full of sources of free radicals..and the electrons in double bonds are just aching to play along, hence creating a chain reaction: initiation, propagation, and finally, termination. Think polymers here, for that what you end up with. (ever heard of acrylic paints? same reaction.) This is why some people believe (although this hasn't been proven yet) that taking vitamin E (a good free radical "eater") is a good idea for a healthy diet.

hope this helps....

yea..yea...too much info..right? ;-)

Answer 4

saturated fats have more energy stored, so body gets more ATP from them, so fat can be formed in your body from glucose, carbs, lipids and proteins and be stored on adypocites, meaning you'll get fatter. Besides all that fat can easily become an ateroma inside your arteries. That's on health, this also is the beginning of high blood pressure.

Unsaturated give less energy, but they also DO the same in your body as unsaturated, only at a slower rate.