The health benefits of raisins include treating constipation, acidosis, anemia, fever, and sexual dysfunction. They have also been known for aiding in a healthy weight gain, as well as for their positive impact on the eye, dental, and bone health.
When ingested, raisins swell because the fiber present in them shrinks in a dried form, and then begins to swell due to the natural fluids. This adds bulk to the food moving through the intestinal tract and ultimately helps provide relief from constipation. The type of fiber in raisins is considered insoluble fiber because it takes in water and gains volume in that way. Besides reducing constipation, they can also help to stop loose stools, again by absorbing its liquid and reducing the frequency and unpredictability of diarrhea.