Is consuming ground flax seeds beneficial? How much if so, and does it really cleanse the intestines? What else should we add/not add to daily diet?

Flax seeds. Ground flax seeds can be beneficial, although it is not as beneficial as a good fish oil, flax is not as well absorbed as fish oil and one of the main reasons for taking either is to increase the intake of fatty acids such as omega three oils. Flax is used mainly by those who want a vegetarian source of omega 3 and can not eat fish or take fish oil.
It's fiber. Flax seeds contain fiber, as well as omega 3 fatty acids. I have heard that some folks become constipated due to too much, too soon, until the body becomes accustomed to the extra fiber. You must drink plenty of water as well. Finally, the colon does not to be "cleansed." the human body is able to keep our internal organs 'clean.' the whole colon cleanse deal is a fad and a myth.