A long-term, high-fat diet may reduce the lacrimal gland’s tear secretion ability, which in turn could cause dry eye, a new study claims.

The investigation, presented Monday at ARVO, included mice that were given either a standard or high-fat diet for different durations over the period of one to four months. Investigators shifted some of the mice to the standard diet for one month after previously being on the high-fat diet for the same time period. Additionally, some mice on the high fat diet were treated with fenofibrate for one month. Researchers evaluated tear production with phenol red thread and examined the lacrimal glands.

After one month, the study found those on the high-fat diet had decreased tear secretion. Other key findings included:

  • Acinar cells of the lacrimal gland showed lipid droplet accumulation increased with time.
  • Cholesterol from the lacrimal gland gradually increased.
  • Enzymes of fatty acid oxidation were disordered.
  • The expression of PPAR-αα gene gradually increased from one month to three months after being on the high-fat diet and decreased after four months.
  • The lacrimal gland showed cell infiltration around the acinus starting at one month of the high-fat diet.
  •  Immumohistochemical and staining and immumofluoerescence staining revealed inflammatory cells infiltration increased.
  • Those on the high-fat diet for four months also showed mitochondria hypermegasoma.

Also of note: After four months on the high-fat diet, mice that were shifted to the standard diet for one month were able to recover from most pathologic changes. In addition, after feeding with fenofibrate, the tear production increased, lipid droplets reduced, inflammation was relieved and the oxidative stress level decreased.

A long-term high-fat diet could induce lipid peroxidation, inflammatory cell infiltration, mitochondria damage, cell apoptosis increase and proliferation inhibition in the lacrimal gland. This could result in aqueous tear secretion decrease, which may induce dry eye, the researcher said.

“Inflammation and associated structural morbidity has been shown to be evident in many DED studies, including this one, and continues to drive home the point that inflammation is both the cause and effect of DED,” explains Joseph Shovlin, OD, of Northeastern Eye Institute in Scranton, PA. “Diet influences many aspects of health, including influences in biomarkers in even more morbid diseases. For example, changes in diet influence cancer risks as well.”

He X, Zhao Z, Bu J, et al. High fat diet induced functional and pathological changes in lacrimal gland. ARVO 2019. Abstract 1416.