20 augusti 2012 kl 10:59
Redigerad 20 augusti 2012 kl 11:07
"Ja, varför behöver folk egentligen glasögon då evolutionen borde ha utvecklat det bästa ögat :-)"
Helt rätt! Närsynhet orsakas av att föräldrar ger sina barn skräpmat vilket höjer deras halter insulin vilket leder till att ögonen växer för mycket.
http://onlinelibrary.wiley.com/doi/10.1034/j.1600-0420.2002.800203.x/pdfWhen 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.
In a comparable study of 3677 recently
acculturated Eskimos and Indians living
in the Yukon and NorthWest territories,
Morgan & Munro (1973) demonstrated a
similar age-dependent reduction in myopia to that of the Alaskan Eskimos. Figure1 shows that the prevalence of myopia (,25–35%) in the younger subjects
(aged 10–20years) is similar to rates
found in fully westernized countries,
whereas the incidence of myopia (2–7%)
in the older subjects (aged 30–60years)
more closely resembles rates of myopia
among hunter-gatherers. This dramatic
and rapid increase in the prevalence of
myopia in a single generation (.30years
versus ,20years) occurred much too
rapidly to re?ect a sudden reduction in
natural selection pressures"
För vidare läsning rekommenderar jag att läsa på hur IGF-1 påverkar skallstruktur, tänder etc hos afrikanska barn, väldigt fascinerande att se familjebilder och se hur mormor, mor och dotter skiljer sig i skallstruktur och tänder när västerländska kostvanor har introducerats över en relativt kort period.
