Clever snails through chocolate

Flavonoids in dark chocolate make snails smart

28/09/2012

Dark chocolate makes slugs smarter. Numerous studies have already dealt with possible positive health effects of dark chocolate. Especially promising effects were attributed to the so-called flavonoids. The Canadian research team led by Ken Lukowiak of the Hotchkiss Brain Institute at the University of Calgary has now discovered that flavonoids have a very positive effect on the brain's functioning in aquatic snails.

Their investigation supports the thesis that flavonoids also improve human memory, the researchers report in the journal „Journal of Experimental Biology“. In experiments with water snails, the flavonoid-related epicatechin, which is found in cocoa, green tea and red wine, has shown a clearly positive effect on cognitive performance. The Spitzhorns (Lymnaea stagnalis) „reminded“ Under the influence of the epicatechin, much longer conditioned to certain conditioning, the scientists had taught them in short training sessions.

Influence of dark chocolate on memory formation?
Although numerous studies have already shown signs of the positive effects of flavonoids on the human brain, it is almost impossible „Find out how individual components of chocolate improve human memory, as too many external factors influence memory formation“; explained Ken Lukowiak. In collaboration with his colleagues from the University of Calgary, Lee Fruson and Sarah Dalesman, Lukowiak therefore devoted himself to the effects of flavonoids on the relatively simple organism of his favorite animals - the whitetail snail. The water snails are capable of remembering simple relationships over a short period of time and are therefore, according to the Canadian researchers, very well suited to the study of basic memory processes.

Snails with limited memory
The scientists used a simple method for training the snails. They lowered the oxygen content of the water in which the animals were. The snails react to this by opening their breathing hoses on the surface of the water. Normally the animals living in ponds, lakes and rivers breathe through the skin. However, if the oxygen content of the water is too low, extend the breathing tube above the water surface to supplement their oxygen supply, write Lukowiak and colleagues. Once the water snails opened their breathing tube, the researchers nudged it with a wand. The snails can remember this for a certain time and therefore did not open their breathing tubes after training sessions, even with decreasing oxygen content. On average, the snails in the normal state after half an hour of training for about three hours to the conditioning. After that, they opened their breathing tube again as before, the researchers report.

Flavonoids improve memory
To test the effect of the flavonoid in dark chocolate on the snail's memory, researchers mixed the water at a concentration of 15 milligrams of epicatechin per liter. The water snails showed a significantly improved memory under the epicatechin exposure, report Lukowiak and colleagues. Instead of three hours, they remembered about 24 hours of conditioning. When the snails received two training sessions, they were able, under the influence of flavonoids, to keep their breathing tubes closed for a full three days. „Our data confirm the notion that dietary sources of epicatechin enhance cognitive ability“, write the Canadian researchers.

Good news for chocolate lovers
However, it remains unclear how the dark chocolate's active ingredients affect the brain. Here, the antioxidant effect of flavonoids, which contributes to the protection of neurons against free radicals could play a role. But also an acceleration of the molecular processes in the memory formation is a possible explanation, write the scientists. It is clear that the flavonoids act directly on the neurons (nerve cells) in the brain, so the conclusion of Lukowiak and colleagues. Comparable positive effects may also be observed in humans. The concentration of epicatechin in the trials has been equivalent to approximately the amount absorbed by humans during normal chocolate or wine consumption. Thus, half a bar of dark chocolate could significantly improve cognitive performance. „Good news for all chocolate lovers worldwide“, stressed Ken Lukowiak.

Health promoting effect of dark chocolate
Various studies have already given the flavonoids of dark chocolate a very health-promoting effect. Recently, researchers from Monash University in Melbourne had in the trade magazine „British Medical Journal“ A study published that daily consumption of chocolate bars with cocoa content of 70 percent reduces the likelihood of stroke. The study was based on data from a total of 2,013 women and men, all of whom had hypertension. Earlier research also found that dark chocolate protects against cardiovascular disease and heart attack. In all previous studies, phytochemicals or cocoa flavonoids have been held responsible for the positive health effects of dark chocolate. (Fp)

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Image: Thomas Siepmann