I completely know the feeling! When I got my first results I almost did a flip in the restroom. I remember having this problem since I was very young; when I had the chicken pox is when I noticed it first. Iím 25 now so trust me Iíve got an army of embarrassing stories, but Iíll stick with your questions.
I donít know if the brand of Flaxseed makes a difference. I bought my first small bag from pavilions which is much like a safe-way or Vons. Then I got my second from GNC and its called Brush Creek/ Organic Foods/ certified organic / Golden Flaxseed, for $8.00. Most flaxseeds are not genetically modified so I donít worry about brands. I buy my Flaxseeds (un-chopped) so that I can chop/ blend it myself with a blender. I prefer my seeds whole because I chop them with a blender and in the end result you see some chopped and some still whole. If you look at your stool the following day itís the same, some chopped and some not. The mix makes for a great cleanse. If you notice in the highest Fiber breads like whole gain wheat flour, flaxseed is always included in its whole form. You may notice in Flaxseed Oil forms itís taken by people who exercise a lot because it has a loosening effect on joints, not so much for its fiber because most of the fiber lingers near the bottom anyways.
You asked a great question regarding diet, this is very important. There some foods that if eaten will always be bad for lingering in the colon. Like red meat for example. It has no fiber which makes it very hard to pass it through completely. I eat a lot of whole wheat pasta, rice, tortillas, bread for fiber value. These foods bulk up the stool making it great for your GI system. If you want a good starting point for changing your diet, this is where I started. http://www.helpforibs.com/diet/fiber1.asp
Make sure that you donít eat too late as this makes it hard for your body to digest food properly. A word on when to take the flaxseed, I notice best results if taken between lunch & dinner. I donít soak my seeds in water I just add water and fruit, and then blend. If youíre not noticing a difference, Iíd increase my intake. But thatís just me. I bought Devrom, chlorophyll and digestive enzymes to try and stop this odor, but then the flaxseedís stopped it. So in a nutshell Iím eating high fiber (water soluble for bulking) foods, chicken and flaxseed with fruit.
Hopefully it works for you. I only started looking for a remedy 2 months ago. I knew I could get the right combo for my body. It was just a matter of time. Keep trying, looking and asking.