A Lexington gastroenterologist testified in Fayette Circuit Court on Thursday that there was no conceivable way for a person to ingest a lethal dose of vinegar.
The testimony related to the death of Joseph Adams, 5, in December 2011. His mother, Deah Adams, was indicted in September 2012 on a charge of reckless homicide. She is free on bond pending trial.
On Tuesday, pathologist Cristin Rolf, who performed the autopsy on Joseph, testified that he died from a lethal amount of vinegar administered by his parents. That finding led to the charge against Deah Adams.
But on Thursday, gastroenterologist Jerry Yon supported testimony from fellow gastroenterologist Craig McClain, who testified Tuesday that there was no scientific data suggesting a person could die from vinegar ingestion.
Yon said vinegar was an extremely weak acid, especially when compared to stomach acid, and that it could even lower the strength of other acids. He added that he had never seen any case of vinegar damaging the intestinal system.
Yon also said that he did not consider Rolf's theory to be credible.
"I don't know how one could jump to that conclusion," he said. "I don't consider that a scientific conclusion."
The most likely cause of death was asphyxiation, Yon said, caused by inhalation of vomit, which blocked Joseph's airway.
Joseph was on a dairy-restricted diet because of Hirschsprung's disease, which affects the colon, and his parents tried to induce vomiting after he drank milk and ate butter.
The autopsy showed signs of a struggle, with bruises on Joseph's head and body. Rick Adams, Joseph's father, said he slapped Joseph while struggling to get him to drink the vinegar to induce vomiting.
Yon said consuming large amounts of butter or margarine could lead to vomiting.
Judge Pamela Goodwine said her job was not to decide precisely what killed Joseph but to decide whether the theory posited by Rolf was credible enough to use in court. Goodwine has yet to render a decision.
A status hearing is scheduled for 1 p.m. Sept. 11.