More on the Benefits of Blueberries

In several earlier posts, I discussed experiments that indicate blueberries can improve memory. There is a more recent study in 9 older adults (average age was 76) who were showing early signs of deterioration in memory capability. For 12 weeks, the subjects were given daily doses approximately 2.5 cups (exact amount adjusted according to body weight) of juice made from commercially available frozen wild blueberries. Berries were thawed, pressed, filtered, pasteurized, and then bottled. A comparison group drank the same amount of fake blueberry juice.

The subjects were instructed to refrigerate the juice at home and to take prescribed daily quantities in equal, divided dosages with the morning, midday, and evening meals. Memory tests (word-pair association, word list) were given before and after the test period. Significant gains in memory ability were seen in the blueberry group. Scores on both kinds of memory tests increased about 33%.

Additionally, there was suggestive evidence that blueberry juice reduced signs of depression and lowered blood glucose levels. This needs to be pursued in future research.

In an earlier post I had summarized a study that showed that milk protein interfered with the blueberry effect. Presumably other proteins could also interfere. In other words, I am suggesting that even better results might be obtained if the juice is taken on an empty stomach (assuming of course that this does not cause upset stomach).

The beneficial effects of the blueberries are thought to be linked to their flavonoid content - in particular anthocyanins and flavanols. The exact way in which flavonoids affect the brain are unknown, but they have previously been shown to cross the blood brain barrier after dietary intake.

Source:
Krikorian, R. et al. (2010) Blueberry supplementation improves memory in older adults. J. Agricultural and Food Chemistry. doi: 10.1021/jf9029332