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Definition: "An ergogenic aid is any substance or phenomenon that enhances performance "
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08.02.2014 |
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Polyphenols in food extend life expectancy
Polyphenols found in fruit and vegetables do wildly interesting things with cells in test tubes and in lab animals. Polyphenols inhibit cancer cells, protect blood vessels, activate the manufacture of connective tissue, protect muscles, prevent the formation of plaques in the brain, stimulate fat burning and help cells carry out repairs on themselves. On paper a diet that is rich in polyphenols should extend life expectancy, but scientists see surprisingly little evidence of this in epidemiological studies.
Another reason is that epidemiologists reconstruct people's eating habits from questionnaires that they have filled in. The data obtained from these is often unreliable.
The Spanish researchers followed 807 people over the age of 65 for 2 years and measured polyphenol intake in two different ways: in the classical way, using questionnaires, and in a more objective way, by measuring the quantity of polyphenol metabolites in the participants' urine. The researchers expressed their results in gallic acid equivalents. The structural formula of gallic acid is shown below.
The classical method resulted in a somewhat disturbing effect on mortality rate. The more polyphenols the over 65s said they ate, the greater their mortality risk seemed to be.
But when the researchers looked at the number of gallic-acid equivalents [GAE] in the participants' urine they saw a positive effect. And, as the figure above shows, this was pretty strong too.
The figure below shows that the addition of alpha-lipoic acid to the cocktail led to a significant increase in the concentration of phosphocreatine.
The figure below shows another summary of the results. The mortality risk of the participants in the tertile with the highest intake was 30 percent lower than that of the participants with the lowest intake.
"The findings from our study suggest that high total urinary polyphenol concentrations are associated with reduced all-cause mortality in an elderly, free-living population, whereas no significant association was found using total dietary polyphenol intake", the researchers write. "Further investigations are needed to confirm this protective association in other populations, especially younger people and different countries with higher dietary variability."
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