X-Message-Number: 16055
Date: Sun, 15 Apr 2001 20:28:33 -0700 (PDT)
From: Doug Skrecky <>
Subject: 37'th update on fly longevity experiments
This is the 37'th update of my fly longevity experiments.
In this run I investigated whether further decreasing the pH
of the fly food improves survival. All bottles except the
citric acid 1/2 tsp, and the tartaric acid 1/4 tsp, contained
citric acid 1/4 tsp as a standard additive.
Doubling the amount of citric acid did indeed increase maximum
lifespan quite remarkably from the control's 66 days to 100 days.
Average survival was only increased slightly from 49 days to about
60 days.
It is interesting that although substituting tartaric for
citric acid exerted a toxic effect on longevity, there was still
no evidence of pathogen growth. I do not attribute this difference
to any special antiaging effect of citric acid. Tartaric acid has
earlier been shown to be somewhat toxic to flies in a published
paper. I'll have to try other acids to see if further differences
occur.
Ginkgo biloba has been found to exert a longevity promoting
effect in rodents. It appears to benefit flies as well.
I tested ephedrine and hydroxytryptophan, as these have
been used as antiobesity drugs in humans. There have been concerns
about ephedrine increasing stroke risk in humans. High dose ephedrine
did reduce average longevity in flies, but paradoxially increased
maximum survival.
Inositol has been touted as a non-toxic inhibitor of cancer.
In the present test it looked fairly safe for flies.
Run #37 Percent Survival on Day
supplement 31 37 44 49 54 61 66 72 76 83 88 94 100 106
____________________________________________________________________
control 71 68 57 50 29 11 11 0 - - - - - -
citric acid 1/2 tsp 86 82 79 68 61 46 39 25 25 25 14 14 4 0
ephedrine 12 mg 58 50 45 32 32 21 21 16 16 3 3 0 - -
ginkgo 20 mg 89 87 71 69 60 53 49 38 36 22 20 9 0 -
horse chestnut 8 drops 83 74 71 63 51 43 37 31 29 14 3 3 0 -
hydroxytryptophan 12 mg 82 53 53 39 24 11 11 3 0 - - - - -
inositol 550 mg 66 63 56 56 53 34 31 22 22 9 3 0 - -
tartaric acid 1/4 tsp 3 3 3 0 - - - - - - - - - -
In Freezer Run #9, I retested green tea polyphenols, and took
another look at whey protein. Green tea proved to be a bust this time.
I'd noticed that the freezing experiment results have much poorer
reproducibility than the fly longevity tests. However once again whey
did apear to offer some benefit. Further testing of whey is warrented.
The flies were fed the various supplements for 4 days, before
freezer storage testing. The highest dose of green tea proved to be
surpisingly toxic.
Freezer Run #9 Percent Survival After
supplement/20 gm food 0 30 60 minutes
_______________________________________________
control 100 33 0
green tea polys 150 mg 100 27 0
green tea polys 300 mg 100 38 7
green tea 300 mg + whey 4 tsp 94 69 0
green tea polys 600 mg 100 36 0
green tea polys 1200 mg 50 30 0
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