While drinking coffee has immense health benefits, there are some dangerous downsides too. According to a recent study, scientists have revealed that instant coffee could increase the risk of a sight-robbing eye condition.
Scientists from the Hubei University of Medicine in China have found that instant coffee can cause age-related macular degeneration, or AMD - an eye disease that causes blurred or no vision in the center of the visual field, typically affecting people over 50 years of age. According to doctors, it is a leading cause of vision loss in older adults, though it does not lead to complete blindness.
However, it does make reading and recognising faces extremely difficult, and symptoms get worse without treatment.
The study, which used genetic data from more than 500,000 people, found a statistically significant link between the intake of instant coffee and the risk of dry AMD - one of the forms of this condition. However, in contrast, ground coffee and decaffeinated brews had no links to AMD.
"Our results revealed a genetic correlation between instant coffee consumption and dry AMD," Siwei Liu of the Department of Ophthalmology in Shiyan Taihe Hospital at the Hubei University of Medicine wrote in the journal Food, Science and Nutrition, where the study was published. "Instant coffee may increase the risk of AMD, and reducing its intake could help prevent dry AMD. People at high risk for AMD should avoid instant coffee," he added.
AMD is a common eye disease and "one of the leading causes of irreversible blindness", researchers said.
How does drinking instant coffee lead to AMD?
According to experts, even though it is unclear how coffee can lead to this condition, genetic factors play a major role in the development of AMD. "However, given the unclear disease mechanisms and the complexity of treatment, slowing disease progression and timely prevention are particularly important."
Previous research has suggested that drinking coffee may help lower the risk of AMD.
"In contrast, our study provided a more detailed stratification of coffee types and yielded different results, indicating potential biases in previous research," the study authors stated. Their results showed "a potential genetic correlation between instant coffee consumption and both dry and wet AMD". Experts also said they found a significant overlap between the genetic predisposition to instant coffee intake and the risk of dry AMD, which suggested shared DNA signals between the two traits across the human genome.
The inference of the research was that processing byproducts, additives, preservatives and chemicals found exclusively in instant coffee can be behind the heightened risk of dry AMD.
What are the chemicals found in instant coffee?
According to the study, instant coffee contains chemicals like acrylamide - which is highly carcinogenic - oxidised lipids, and other compounds which are not there in fresh brews.
Also, various other research has concluded that those with early-stage AMD should consider reducing their intake of instant coffee and should rather opt for ground beans.
What are the signs and symptoms of AMD?
Macular degeneration affects your central vision, severely destroying your retina. Those who have macular degeneration are not completely blind. Their peripheral vision (ability to see things off to the sides) is fine. A few signs and symptoms of the condition include:
