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Date: | Tue, 20 Jan 1998 09:22:39 +1100 |
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In Steffan Lindberg's last post he wrote:
According to Mayhall [1],
"The frequency of the occurence of shovel-shaped incisors is generally held
to be greatest in Mongoloid populations and lower in other groups. ... In
general, populations native to Asia and North America have the deepest
lingual fossae (larger than 0.9 mm), South Americans having intermediate
depths (0.5-1.0 mm) and Europeans the shallowest (0.3-0.7 mm). If only the
larger expressions (shovel and semishovel) are included, one can generalize
and show that North and South American natives demonstrate an occurence of
70%-95%, Asians about the same as the Amerindians, Melanesians
approximately 6%-20%, Australian Aborigines about 60%-90%, Europeans 5%-50%
and Teso and Bantu from Africa between 10% and 20% [2]. In North America,
Indians and Inuit have about the same occurence of the trait, but the
Indians have the larger expressions [3].
As I read this, I was struck by the fact these same prevalence figures
could be applied to the genetic trait of insulin resistance which results
in non-insulin-dependent diabetes (NIDDM) under adverse environmental
conditions. If 'shovel-shaped incisors' tell us anything about diet, then
this same diet may have selected for insulin resistance. Or alternatively,
the very shallow lingual fossae of Europeans might tell us why Europeans
have such a low prevalence of NIDDM.
So what exactly do 'shovel-shaped' (or the opposite) incisors tell us about
diet? Are we guessing or are their some facts?
Best wishes Jennie
Jennie Brand Miller PhD
Associate Professor in Human Nutrition
Department of Biochemistry G08
University of Sydney
NSW 2006 Australia
Phone: (61 2) 9351 3759
Fax: (61 2) 9351 6022
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