The Durk Pearson & Sandy Shaw®
Life Extension NewsTM
Volume 9 No.
3 • August 2006
Blueberry Polyphenols Increase Lifespan and Thermotolerance in C. elegans
In this new study, the authors report further beneficial effects for blueberry polyphenols, including extended lifespan. While adult wild-type C. elegans grown under the authors’ standard lab conditions had a mean lifespan of 12.7 days, with an average maximum lifespan of 19.7 days, on media containing either crude blueberry extract or their bulk polyphenols, the mean lifespan of wild-type animals was increased by 28%, and the maximum lifespan increased by 14%. The blueberry extract or polyphenols slowed aging by, for example, decreasing the accumulation of intracellular lipofuscin (reduced by 20% in treated animals) and reducing the production of 4-hydroxynonenal, a lipid peroxide breakdown product.
This study is particularly interesting because the researchers examined the effects of three different fractions of the blueberry polyphenols: one enriched in anthocyanins, one in proanthocyanidins, and the other in hydroxycinnamic esters (mainly chlorogenic acid). The only one of the three fractions that affected lifespan was the one enriched in proanthocyanidins; treatment with the proanthocyanidin-enriched fraction increased lifespan to a similar extent as the starting blueberry polyphenol mixture. Oddly, although the blueberry polyphenols increased thermotolerance in the treated C. elegans, blueberry treatment was not consistently associated with greater HSP (heat-shock protein) mRNA induction following heat shock, as compared with untreated controls.
More about proanthocyanidins
Proanthocyanidins, better known as condensed tannins, are found in many foods, such as tea, grapes, cherries, strawberry, cinnamon, red wine, and cocoa. They are mixtures of oligomers (a few monomers polymerized together) and polymers composed of flavan-3-ol units linked together in various ways. The proanthocyanidins consisting exclusively of polymers of (epi)catechin units are designated as procyanidins. Interestingly, proanthocyanidins appear to be degraded during drying; whereas plums and grapes contain them, they are no longer detectable in prunes and raisins. Vegetables are not an important source of proanthocyanidins. However, most nuts (e.g., almonds, pistachios, pecans) contain them, and they are also found in beer (from hops).
- Wilson et al. Blueberry polyphenols increase lifespan and thermotolerance in Caenorhabditis elegans. Aging Cell 5:59-68 (2006).
- Gu et al. Screening of foods containing proanthocyanidins and their structural characterization using LC-MS/MS and thiolytic degradation. J Agric Food Chem 51:7513-21 (2003).
- Santos-Buelga and Scalbert. Proanthocyanidins and tannin-like compounds—nature, occurrence, dietary intake, and effects on nutrition and health. J Sci Food Agric 80:1094-117 (2000).
- Li and Deinzer. Structural identification and distribution of proanthocyanidins in 13 different hops. J Agric Food Chem 54:4048-56 (2006).