Canibais e Reis

A teoria do Dr. Loren Cordain relativa à miopia juvenil, mais uma doença da civilização potenciada pela insulinémia crónica, está a ganhar suporte. A este respeito, leia-se o seu artigo na Acta Oftalmológica Escandinava (ver mais abaixo), bem como estes dois artigos relacionados com este tema:

TV, Computers Cause Irreparable Harm To Eyesight (The Independent UK)

Generation specs: Stopping the short-sight epidemic (New Scientist)

Are your eyes what you eat?

Seven years ago, evolutionary biologist Loren Cordain at Colorado State University in Fort Collins caused a stir by suggesting that myopia may be triggered by the excessive consumption of refined carbohydrates. The study compared diets and rates of myopia in different nations, and it seemed plausible that insulin levels which were raised in response to a high-carb diet could stimulate the eye to grow and become elongated, causing myopia.

This year, two independent studies, led by Frank Schaeffel at the University of Tübingen in Germany and Josh Wallman at the City College of New York, have provided further evidence that insulin can stimulate eye growth. Working with chicks that wore special lenses to provoke myopia, they found that injecting insulin into the chicks’ eyes increased the deterioration in their sight dramatically.

Yet whether this explains the link between diet and myopia remains hotly debated. "Initially we just didn’t believe Cordain’s carbohydrate story, but now that we know that insulin can interfere so much, I am not so sure," says Schaeffel. Wallman remains more doubtful, arguing that a high-carb diet may not necessarily raise insulin levels in the eye enough to cause damage.

Cordain cites studies which found that people with high blood-sugar levels are more likely to be myopic, and says that insulin levels in the eye do seem to reflect levels elsewhere in the body. High blood sugar may also promote myopia by raising levels of the growth factor IGF-1, a substance which likewise stimulates eye growth, he says.

 

Fonte: Generation specs: Stopping the short-sight epidemic.

  E aqui está o artigo do Dr. Loren Cordain, do qual também é autor o Dr. Staffan Lindeberg:

Acta Ophthalmol Scand. 2002 Apr;80(2):125-35.

An evolutionary analysis of the aetiology and pathogenesis of juvenile-onset myopia. (pdf)

Cordain L, Eaton SB, Brand Miller J, Lindeberg S, Jensen C.
Department of Health and Exercise Science, Colorado State University, Fort Collins, Colorado 80523, USA.

The available evidence suggests that both genes and environment play a crucial role in the development of juvenile-onset myopia. When the human visual system is examined from an evolutionary perspective, it becomes apparent that humans, living in the original environmental niche for which our species is genetically adapted (as hunter-gatherers), are either slightly hypermetropic or emmetropic and rarely develop myopia. Myopia occurs when novel environmental conditions associated with modern civilization are introduced into the hunter-gatherer lifestyle. The excessive near work of reading is most frequently cited as the main environmental stressor underlying the development of myopia. In this review we point out how a previously unrecognized diet-related malady (chronic hyperinsulinaemia) may play a key role in the pathogenesis of juvenile-onset myopia because of its interaction with hormonal regulation of vitreal chamber growth.

Download: myopia-loren-cordain.pdf