Pesticide Found In Milk May Increase Parkinson’s Disease Risk Later in Life: Study

New research suggests that men who consumed milk that was tainted by a now banned pesticide may have a higher risk of developing Parkinson’s disease later in life, raising further concerns about the organochlorine pesticide heptachlor epoxide, which was widely used in the Pineapple industry, prior to being removed from the market in the late 1980s. 

The study was published last week in the medical journal Neurology, indicating that men from Hawaii who drank more than two cups of milk per day, which may have contained the pesticide heptachlor epoxide, had a higher loss of brain cells.

Researchers from Japan examined milk intake and brain cells of nearly 450 Japanese-American men between the ages of 45 to 69 years of age, who were a part of the Honolulu-Asia Aging Study. The milk consumption data was collected between 1965 and 1968, from men who lived in Hawaii, and the participants were followed up for more than 30 years, from 1992 to 2004 or until their death.

Following death, an autopsy was performed post-mortem. Participants had the amount of residue of the pesticide in their brains measured, as well as the neuron density in specific quadrants of the brain.

Researchers found men who regularly drank more than two cups of milk, or 16 ounces, lost 41% more brain cells than men who drank low amounts of milk.

“The link between dairy products and Parkinson’s disease has been found in other studies,” said study author R. D. Abbott, PhD, with the Shiga University of Medical Science in Otsu, Japan. “Our study looked specifically at milk and the signs of Parkinson’s in the brain.”

Residue of heptachlor epoxide was found in 90% of the brains of men who were regular milk drinkers, compared to 63% for men who were not.

Heptachlor epoxide is an organochlorine pesticide found at high levels in well water and at excessively high levels in the milk supply in Hawaii in the early 1980s. It was used in the Pineapple industry to kill insects and was removed from use in the U.S. in the late 1980s.

Parkinson’s disease is known to be linked to loss of brain cells in the substantia nigra area of the brain. The decline can start years, even decades, before any symptoms begin.

Researchers also found that the men who were smokers or had ever smoked at a point in their life had less neuron loss. Researchers say other studies have shown smokers have a lower risk of developing Parkinson’s disease.

Overall, the study did not show the pesticide in the milk caused Parkinson’s disease, it simply showed a link between the two. Additionally, researchers said they could not prove the milk consumed by the men had heptachlor epoxide in it or not.

“Also, milk consumption was measured only once at the start of the study, and we have to assume that this measurement represented participants’ dietary habits over time,” said co-author of the study Honglei Chen, MD, PhD, with the National Institute of Environmental Health Sciences.

The study was funded by the National Institute on Aging, National Heart, Lung and Blood Institute, National Institute of Neurological Disorders and Stroke, the Department of the Army, Department of Veterans Affairs and the Kuakini Medical Center.