Alcohol tolerance and pain tolerance are shown through... eye color

Not only are they the "windows to the soul", eyes and especially eye color can also reveal your health status and some of your abilities.

The link between eye color and health has fascinated scientists for years, leading to a series of elaborate studies showing that eye color affects how much pain an owner feels, his or her risk of diabetes, mental processing speed, and even his or her alcohol tolerance.

The latest research by experts from the University of Pittsburgh (USA) discovered that Caucasian women with light-colored eyes (blue or green) seem to endure pain and exhaustion better than their counterparts with brown or golden-brown eyes.

Additionally, women with lighter-colored eyes also reported less postpartum anxiety, lower rates of depression, and fewer negative thoughts.

Although more research is needed to find out the exact cause of this difference, experts say it is most likely due to a genetic connection.

Until recently, it was thought that there was only one gene for blue eyes and another for darker eyes. However, according to Dr. Jari Louhelainen, senior lecturer in molecular biology at Liverpool John Moores University (UK), this assumption is completely wrong, because researchers now know that eye color is based on 12-13 separate variations in human genes.

As for why eye color might determine our health, Dr. Louhelainen explains that it's because the genes that determine eye color can have multiple roles. For example, the gene NCX-4, which is associated with darker eyes, controls multiple proteins involved in pain.

Other genes linked to melanin, the pigment that darkens eyes, have also been linked to pain. For example, Dubin-Johnson syndrome, a genetic liver disease that turns liver cells brown, is linked to melanin buildup. Symptoms include pain and fatigue.

Melanin may also make brown-eyed people more vulnerable to alcohol and more likely to get drunk. Meanwhile, light-eyed people have a better alcohol tolerance and tend to drink more alcohol.

Melanin not only determines eye color, but also insulates the electrical connections between brain cells. The more melanin we have, the faster, more responsive, and more efficient our brains are, according to a study published in the journal Personality and Individual Differences. This advantage in brain processing speed may help explain why brown-eyed people tend to have faster reaction times and are better at tennis and badminton than blue-eyed people.

A 1991 study by psychologist Dr. Anthony Fallone of the University of Edinburgh (UK) also showed that students with dark eyes achieved significantly better results in many time-limited intelligence tests, where thinking speed provided a definite advantage.

Meanwhile, the slower reaction times of blue-eyed people may suggest that they think more strategically and deliberate more carefully. According to tests at the University of Louisville (USA), blue-eyed students proved to be more successful in activities that require planning and time allocation, such as playing golf, running marathons and studying for exams.

Studies have also found evidence that people with blue eyes are more likely to develop type 1 diabetes and have hearing problems than people with darker eyes. In particular, in terms of personality, people with blue eyes are more shy, timid and anxious than people with brown eyes.

According to Vietnamnet