Anthocyanins
The Color Purple
No, not Steven Spielberg's 1985 hit movie based on Alice Walker's novel The Color Purple. We're talking about anthocyanins (antho-sigh-an-ins), the antioxidant plant pigments called flavonoids or polyphenols. These compounds provide the purple-red color of petunias, pansies, as well as purple cabbage, plums and the skins of purple grapes and eggplants. Anthocyanins are also concentrated in European bilberries, which were reported to improve British pilots' night vision in World War II. More recently, researchers have examined bilberry's close relative, the North American blueberry, as well as the polyphenols in red wines. As a result, scientists are gaining a better understanding of how polyphenols work and their potential health benefits.
A brain power connection?
Researchers at Tufts University found that among five dozen different types of fruits and vegetables, blueberries have one of the highest scores on a lab test that measures antioxidant capacity – the capacity to destroy potentially damaging free radicals. The scientists attribute this potent antioxidant action to the blueberry's high anthocyanin content. In a subsequent experiment, aging rats were subjected to a battery of tests after being fed healthful diets supplemented with spinach, strawberry or blueberry extract or nothing at all. The blueberry-fed rats fared better at tests for balance and coordination, while rats on all three of the fruit and vegetable diets performed better on memory tests than did rats on the control diet.
According to the investigators, anthocyanins may help squelch free radicals that diminish brain function, and by making the membranes of brain cells (neurons) more fluid. Cell membranes become more rigid as we age, making it harder for signals or messages in the brain to go from one neuron to the next. More research is needed to see whether anthocyanins can actually impact the age-related decline in human brain function.
Red wine may fight heart foe
If you indulged in a good cabernet sauvignon this holiday season, you may have been helping your heart as well as your spirits. Population-health studies have linked red-wine consumption to better heart health. Red wines contain anthocyanins, proanthocyanins (a precursor of anthocyanins) and other polyphenols. Some scientists theorize that wine drinking explains why the French appear to have a lower risk of heart disease than other westernized countries despite eating similar amounts of saturated fat – a phenomenon known as the French Paradox.
A study published last month provides new clues as to how red wine might exert a heart-healthy effect. The study, which exposed cultured heart cells to non-alcoholic wine extracts, suggests that red wines suppress the formation of a peptide that makes blood vessels constrict. Compounds that block this peptide may be involved in reducing fatty streaks in arteries. White and rose wines had no effect on the production of the peptide, called endothelin-1. This implies that the active components are polyphenols from the grape skin, which are found only in red wines. This study, if confirmed, adds deeper meaning to the toast "to your health"!
- Tufts University Health & Nutrition Letter; 19:4-5, March 2001.
- Corder R, et al. Endothelin-1 synthesis reduced by red wine. Nature; 414:863-4, Dec 2001