There are a few supplements that I feel are the most important to be taken along with a diet, such as the GAPS diet, to help heal the gut and restore needed nutrition to our bodes.
These few supplements are:
L-Glutamine, Probiotics, Cod Liver Oil, and possibly even a good mutli-vitamin and mineral liquid.
As for the L-Glutamine: I only trust the brands from our local health food store. L-Glutamine, if in capsule form, can be opened and poured into any food we (or our children) are eating.
L-Glutamine helps to regenerate the tissue within the gut wall and helps to protect it as well.
As for Probiotics: I'd recommend Garden of Life's Primal Defense probiotics. These probiotics, of course, are used to help reestablish the digestive systems beneficial flora.
Although I've heard that Blue Ice's fermented cod liver oil is the best - I'd still buy a good brand from my local health food store.
A lot of times if someone has an impaired digestive system they're unable to get the nourishment from the foods they're eating and therefore a good vitamin and mineral liquid is important to help the healing process along. Yes, juicing is ideal for this but some may need an added boost along with this. There are many good liquids found at local health food stores. The brand I use is called Miracle 2000.
There may be more I add here but for now, these are the tops.