Doc told me to get extra fiber due to a problem I had last year. Remember there are two kinds of fiber, soluble and insoluble. Metamucil is largely the soluble type, flax seed and wheat bran are insoluble. Both are helpful in "keeping the pipes clean". There are other fiber supplements like Fiber Choice and Fiber Sure that use inulin, which is also soluble. For heart health, I understand that the soluble is more helpful.
Personally I keep a bottle of Fiber Sure at work for when I don't have time to eat properly and only have time for a protein shake. Just mix in some Fiber Sure into it. I also keep a bottle of Fiber Choice sugar free chewable tablets at work for when my lunch has little or no fiber in it. After dinner, I take T-Al's ElderTang (metamucil) usually in the pink lemonade flavor since it seems to go best in plain water. I have to mix the orange and berry flavors with crystal light or something like it. I have found that the Fiber Sure and the Fiber Choice don't seem to help enough with keeping the plumbing clean, unless I have at least one dose of metamucil each day. On the other hand, things are usually just fine if I have the metamucil but don't take the others.
The one that does not seem to have ever done any good for me is Benefiber. Which, when I tried it anyway, was (I believe) made with wheat dextrin. It was absolutely no help in the plumbing department, although it may be beneficial for the heart.
My Dad has to have fiber like I do, and he has gone to the Equate brand of psylium and finds no problem with it, but mixes it with juice. I find it too gritty so I'm sticking with metamucil.
R