James Hrynyshyn
Northern News Services

Yellowknife (May 20/02) - The same bad diet that is widely believed to be the cause of obesity and diabetes may also be responsible for increasing rates of short-sightedness among Inuit and Dene, says an international team of scientists.

In a paper published recently in a leading eye-research journal, evolutionary biologist Loren Cordain and his American, Australian and Swedish colleagues make the case for a link between processed foods and near-sightedness, a failure of the eye to focus properly known also known as myopia.

"The information has been out there for a while," Cordain said in an interview with News/North, but "there's not too many people out there looking at the big picture."

Diets dominated by refined cereals and sugars can disrupt the body's metabolism by decreasing the body's sensitivity to insulin, an important regulatory hormone.

What Cordain's team has done is link that problem with growth of the eyeball.

Their theory is an attempt to explain why the rate of myopia among Inuit, Dene and other hunting and gathering cultures, a disease virtually unknown until the late 20th century, is catching up with the rest of the world. It's estimated as many as 35 to 50 per cent of populations have some degree of myopia.

"It's a mismatch between the environments and the genes," says Cordain, pointing out that in nature, any gene for myopia would be quickly eliminated.

Until now high myopia rates have been related to the introduction of literacy, which involves reading, writing and other so-called "near work" tasks that could strain the eye.

But Cordain's group found that surveys of students in Nepal, Malawi and the remote South Pacific island of Vanuatu show there is likely some other environmental factor behind the difference in rates.

The new theory makes sense, according to Jane Magrum a veteran ophthalmic technologist at the Yellowknife Eye Clinic.

Although there are no data on myopia rates among Inuit and Dene communities, she says only their youth are diagnosed with myopia at rates approaching the Western norm.

"We don't see many people over the age of 60 or 70 that are near-sighted," says Magrum. And that, says Cordain, is exactly what one would expect to see thanks to changing diets.