We absorb mainly in the small intestine, through the small villi which compose the intestinal walls. The absorptive function of these villi may be hampered by certain diets. Some persons may also have an inherent weakness in this area which does not allow them to utilize their foods as well as others. A proper diet is the best way to aid in assimilation. Also adequate rest is needed as a fatigued system cannot absorb well.
On the iridology chart the villi are the first ring next to the pupil. If the ring next to the pupil is a dark redish brown colon then the assimilation is poor. The ring around that is the stomach area. If the ring in the center of the iris is an orangish color like in the iris above the stomach is underacid. If the stomach ring is white then the stomach is overacid.
Herbs such as Alfalfa, Peppermint, Papaya and Ginger are also beneficial. Should the villi become unable to absorb nutrients properly, cleansing may be encouraged using the herb Comfrey and the digestive aid Pepsin as well as a bulk former such as Psyllium Hulls along with Cascara Sagrada.
For more information on iridology go to: http://www.joyfullivingservices.com/iridology.html