Never, under any circumstances, should a person with kidney disease try starfruit or any food made with starfruit. While the Starfruit is a good source of several nutrients, especially fiber and vitamin C, it also contains a toxic substance called a neurotoxin. This neurotoxin can affect the brain and cause neurological disorders. People with healthy, normal kidneys can process and pass this toxin out from their body without any harm. However, for those with kidney disease, this is not possible. The toxin stays in the body and causes serious illness.