Well, mainly because they do not break down lipids.
They only help breaking lipids by emulsifying them and thus enabling enzymes to break them.

Simply, bile salts are amphiphillic and thus are able to bind to lipids and make them to form smaller particles (micelles), which are better accesible for the lipases.

This is something I wrote for a lab report and fell under a similar cateogory….. Does this make sence(already turned it in no grade yet) Just wanted to see what someone else thought. The lab was performed by my partners and I disagreed with their lab results…Anyway what do we think?

Solubility Test: Based on the Solubility Test that my lab partners performed, it was determined that out of 5 different solvents. Three of the solvents were proven to be polar to oil, and two of the solvents nonpolar. Despite the fact that there were nonpolar solvents, it was proven that one could suspend or “mix” lipids that are nonpolar in an aqueous solution by making an emulsion. Two types of emulsions tests were performed; temporary and permanent. This emulsification test was performed by using water and soap water in vegetable oil. As reported by my partners, when the water was mixed with the oil, the water was emulsified temporarily. It then it separated very quickly, in result, showing a temporary emulsion. When the soap was emulsified, it held the liquids together even once time had passed. Both results of the water and soap I agree with based on my previous knowledge of water and soap in regards to oil. An additional test was performed this time using 1% bile salts which was not emulsified at all. I do not agree with this result because bile or bile salts emulsify lipids. When the liver produces bile (in addition to bile salts) it is stored in the gall bladder. When the bile is needed to aid in digestion and emulsify lipids in our system, it is secreted into the digestive tract. The bile helps prevent the absorption of toxins and prevents diseases that occur in result to toxic build up. Soap and bile are very similar when it comes to emulsifying oils or lipids; however, soap is a better emulsifying agent because bile takes a longer time.

what do you mean by polar to oil?

My lab partners actually performed the lab test and explained it to me as "polar". I’m assuming polar as in bonding together and not separating like water and oil. Was polar not the proper way to describe it?
(Taking a bio 121 class never took a bio class like this before mostly life science classes)

definitely not!

http://www.answers.com/topic/chemical-polarity

How would one describe it then?

Polar is not a verb,it is adjective which is related to positive and negative charge.In chemistry,we usually say like this : "A is attracted to B",or,"A attacks B","A bonds to B".So,polar is kinda unsuitable to be describe in your case.Instead,you can use "attracted to",or I think maybe "bonds to" is more suitable since this is in biology.I’m not 100% sure though because my english is kinda lame haha.

Polarity has nothing to do with charge