D, L configuration of sugars and amino acids

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In a message dated 9/20/02 7:04:31 PM,

writes:

>L-left is used for human nutrition D-right is usually not useful for humans.

>

>Most synthetic foods, vitamins, etc are the D. There are some exceptions

>to

>

>the rule, especially when they contain both L and D, but this is generally

>

>the rule.

D (dextrorotatory -- OH group to the right) and L (levorotatory -- OH group

to the left ) are designations to specify the configuration of atoms around a

chiral carbon in sugars and amino acids. The sugars we eat are all of the D

configuration and the amino acids in our food are of the L configuration.

Generally the two configurations have vastly different biological effects.

One configuration might be useful, the other deadly. Usually not sold

together, except D, L phenylalanine -- each form of this amino acid has

different effects thought to enhance mood and neural functioning. Vitamins

are complex molecular structures --most are not designated as L or D

(ascorbic acid is -- L-ascorbic acid) -- the structure has to have a chiral

carbon --has to have a mirror image. There are probably important differences

between naturally derived and synthetic vitamins -- but the D, L

configuration is not one of them. Actually as far as 'isolated vitamins'

are concerned-- not considering synergistic bio-factors present with them in

food -- there is no chemical difference between them according to Linus

ing.

Namaste, Liz

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