Anthocyanins, pigments responsible for the jeweled red, purple and blue tones of plants, are shining in the research world. Anthocyanin-rich foods were part of folk medicine, botanists were fascinated by their role in pollination attraction and phytoprotection, and food scientists investigated anthocyanin color-quality issues in fruits and vegetables. Today, researchers are honing-in on the possible health benefits of anthocyanins, the most-abundant flavonoid in fruits and vegetables.

The promise of health benefits

I think its a very exciting field of research, says James Joseph, Ph.D., research physiologist, Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, Boston. Anthocyanins are fairly good antioxidants and very good at scavenging free radicals. And they alter the compounds that come after free radicals, called stress signals. This protects against a variety of diseases. Other mechanisms may also be at play, such as protection from DNA cleavage, estrogenic activity, enzyme inhibition, regulating immune response through increased cytokine production, anti-inflammatory action, lipid peroxidation and membrane strengthening.

Anthocyanins have been linked to a number of health benefits. Enhancement of night vision or overall vision was documented when anthocyanin pigments were delivered to animals and humans. Three anthocyanins from black currant stimulated regeneration of rhodopsin, a receptor in the retina. And the administration of anthocyanoside oligomer appeared to improve subjective symptoms and objective contrast sensitivity in myopia subjects with eye fatigue.

Cell culture and animal studies have indicated that berry anthocyanins are potent anticarcinogenic agents and protect against genomic instability at several sites in the carcinogenic pathway. Cancer-preventative mechanisms include modulation of carcinogen activation and detoxification, decreased DNA binding of the carcinogen, inhibition of oxiditative DNA damage, alteration in cell signaling and malignant transformation, and inhibition of cell invasiveness and metastasis.

The cardiovascular-disease protection from anthocyanins has a strong connection with oxidative-stress protection. Four anthocyanins from elderberries incorporated into endothelial cells demonstrated significant oxidative-stress protection. Anthocyanins also display a variety of positive effects on blood vessels, platelets and lipoproteins that may reduce the risk of coronary heart diseases.

Another area of research deals with the brain. They have been associated with modulation of cognitive and motor function, enhanced memory and prevention of age-related declines in neural function. Isolated, semipurified anthocyanins from purple sweet potato enhanced cognitive performance in mice and inhibited lipid peroxidation in rat brain tissues. Blueberry extracts appeared to reverse age-related deficits in memory and motor functions in rats.

However, much of the research relates to food sources, rather than isolated anthoycanins. Foods rich in anthocyanins may be calling upon the synergy of many phytochemicals to provide health benefits. The whole is greater than the sum of the parts, says Joseph. Its way too early in the game to say anthocyanins did this or that. There is not enough research out there yet.

Scientists have called anthocyanins an enigma; their study is plagued with complexities. We have barely scratched the surface in anthocyanin research. There are three key areas of concern: stability, bioavailability regarding where it goes and how it gets converted, and degradation, says Joseph. Degradation during extraction procedures makes it difficult to understand their bioactivity. Anthocyanins are extensively broken down after consumption. Thus, tracking their absorption, bioavailability and accumulation in organs is difficult.

Ingredient suppliers are working to boost the stability in anthocyanin ingredients and enhance functionality. In some medium-stable anthocyanins, you can have beverages browning within six months, says Jeff Greaves, president, Food Ingredient Solutions, Teterboro NJ, who also reports that positive metal ions found in formulations with hard water or iron fortification can cause problems with color degradation. But he has found success in beverage shelf life for more than one year using stable anthocyanins from sources like purple potatoes.

One novel combination of berry extracts from InterHealth Neutraceuticals, Benicia, CA, seems to have broken the barrier for anthocyanin functionality. Derived from a blend of wild blueberry, strawberry, cranberry, wild bilberry, elderberry and raspberry extracts, the ingredient contains standardized levels of biologically active anthocyanins.

Sharon Palmer is a registered dietitian with 16 years of experience in health-care and foodservice management. Palmer makes her home in Southern California and can be reached at [email protected] .