Regular Coffee Consumption May Protect Eyesight

Your morning cup of coffee may provide more than just a pick-me-up—it could protect against deteriorating eyesight and even blindness, according to a recent study in the Journal of Agricultural and Food Chemistry.

“Coffee consumption may help in preventing retina degeneration,” says senior author Chang Y. Lee, PhD, a professor of food science at Cornell University, in Ithaca, NY. “The significance of this study is providing additional (evidence of the) neuroprotective effect of coffee as a functional beverage.”
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While raw coffee beans don’t actually pack much of a punch, containing just 1% caffeine, each raw coffee bean boasts about 7% to 9% chlorogenic acid (CGA), a powerful antioxidant. Lee and his colleagues found that coffee—and CGA specifically—had protective effects against retinal degeneration in mice.

“The retina is one of the most metabolically active tissues in the body, consuming oxygen more than any other tissues,” Lee says. “Therefore, it is susceptible to a variety of diseases caused by oxidative stress (caused by free radicals), including age-related macular degeneration, diabetic retinopathy, and glaucoma.”

This lack of oxygen can lead to tissue damage and ultimately vision loss—which is one of the reasons there has been such great interest in identifying neuroprotective compounds that inhibit hypoxia, including antioxidants. 

The researchers treated the eyes of the mice with nitric oxide, which creates oxidative stress and produces free radicals, leading to retinal degeneration. Lee says that under hypoxic conditions, nitric oxide treatment significantly reduced the viability of the mice’s retinal ganglion cells.

However, the retinal ganglion cells that they pre-treated with CGA and coffee extract showed increased cell viability. This protective effect was dose-dependent—cell viability increased by 72.6%, 92.7%, and 101.6% in response to CGA pre-treatments of 25μm, 50μm, and 100μm, respectively.

“We also found that chlorogenic acid and coffee extract significantly reduced apoptosis (programmed cell death) of retinal cells induced by hypoxia and nitric oxide,” Lee says. Both the CGA and the coffee extract reduced cell death by preventing down-regulation of Thy-1, a cell surface protein.

“Since we have not conducted on human clinical study yet, we are not certain the optimum amount and/or frequency of coffee consumption for health benefits,” Lee says. “We hope that our findings will translate to humans who consume coffee regularly, but the credible final evidence will be produced after human clinical studies.”

—Colleen Mullarkey

Reference

Jang H, Ahn HR, Jo H, Kim K-A, Lee EH, Lee KW, Jung SH, Lee CY. Chlorogenic acid and coffee prevent hypoxia-induced retinal degeneration. J Agric Food Chem. 2014;62(1):182-191.