Ouroboros casts a skeptical eye on research I mentioned a little while ago at Fight Aging!: culturing cells using blood serum from calorie restriction (CR) and alternate day fasting (ADF) volunteers before and after the program to examine the differences. "we used sera collected from those studies to culture human hepatoma cells and assessed the effects on growth, stress resistance and gene expression. ... I was concerned by the lack of phenotypic benefits in cells treated with CR sera, as compared to cells treated with ADF sera: The CR-treated cells exhibited no increase in heat-shock resistance, no decrease in cell proliferation, and no correlation of Sirt1 expression to reduced triglyceride levels. In interpreting this finding, the authors suggest that the increased effects seen in the ADF participant serum could be due to the 'short, regular intervals of complete caloric deprivation,' which might provide a more potent serum profile capable of producing the observed in vitro changes. ... Alternatively, I think that these data could be a result of the cell type used in this assay (a tumor line); it would be interesting to see this experiment repeated on primary cells or a non-cancerous transformed cell line."

Link: http://ouroboros.wordpress.com/2008/10/02/feast-and-famine-in-vitro-techniques-to-assess-longevity-diets/