In controlled experiments fruit-eating birds actively chose berries with the highest concentrations of antioxidants – compounds that help them maintain a healthy immune system.

Published in the British Ecological Society’s Functional Ecology, the study claims to be the first to prove the connection between flavonoid consumption and stronger immune systems.

Researchers were able to show for the first time that antioxidants – known as flavonoids – boosted the immune system of a living creature as opposed to laboratory studies.

A team from the University of Freiburg and the Vogelwarte Radolfzell at the Max Plank Institute for Ornithology in Germany offered a group of blackcaps – known as the ‘northern nightingale’ because of its fluting song – a choice of two foods. The foods were identical except for the amount of flavonoids they contained,

They found that the blackcaps actively selected the food with added flavonoids and this had an impact on their health.

Blackcaps that ate modest amounts of flavonoids for four weeks had stronger immune systems compared to birds not fed the antioxidants. Iinjected with red blood cells from sheep, 54 percent of the supplemented birds had a positive immune response, compared to 30 percent of the non-supplemented birds.

The levels of flavonoids used were equivalent to the amounts that would have been obtained through eating 1-2 blackberries, bilberries or elderberries a day.

Because the birds weighed only 20g, this would roughly translate into several hundred berries a day for humans.

The birds were able to tell which food had added flavonoids because – as would be the case in nature – flavonoids made the food a darker colour. The research team believes that the blackcaps know that the darker berries contain more flavonoids, and this is why they prefer them.

Posted: 04|5|08 at 9:08 am. Filed under: News.