ITHACA, N.Y. -- New York state red wines have higher levels of resveratrol -- a naturally occurring substance in grapes that has been found to reduce the chance of heart disease and cancer -- than comparable wines from other regions of the world, according to Leroy Creasy, Cornell University professor of fruit and vegetable science. Creasy recently completed an analysis of more than 100 red wines from five states and foreign countries.
Although resveratrol is a compound found in some other plants, grapes and grape products -- particularly wine -- are the most substantial sources.
(The first study showing resveratrol's cancer preventative properties was written by Jang, M., et al., "Cancer Chemopreventive Activity of Resveratrol, A Natural Product Derived From Grapes," Science, Vol. 275, January 1997, pp. 218-220. One of the early references of resveratrol's properties beneficial to the heart include a paper written by Evan H. Siemann and Creasy, "Concentration of the Phytoalexin Resveratrol in Wine," The American Journal of Enology and Viticulture, Vol. 43, pp. 49-52, 1992.)
Creasy's study, consisting mostly of 1995 vintages, included 70 New York state red wines, 19 from California and 22 from other states or countries. New York wines had the highest resveratrol concentration compared with wines from other regions, he found. "Some of New York wines, particularly in the pinot noir category, have extraordinary levels," he said.
Resveratrol concentration is measured in units called micromolar (µM), and an average red wine could have 3 to 4 µM. Wines above 5 µM of resveratrol are considered high, those above 7 are considered very high and any product above 10 is extraordinary, Creasy said. New York wines used for this project came from Long Island, the Hudson Valley, the Finger Lakes and the Lake Erie regions. The California wines came from the Central Coast, Mendocino, North Coast and Sonoma. And the other U.S. wines came from Mississippi, Oregon and the state of Washington. Countries represented include Argentina, Australia, Canada, Chile, France, Italy, Slovenia and South Africa.
The average resveratrol content of all New York wines tested was 7.5 µM, compared with 5.8 µM for non-New York reds and 5 µM for California red wines.
The type of wine with by far the highest resveratrol levels was pinot noir, with 11 of the 17 New York wines registering above 10 µM. For pinot noir, the average levels were 13.6 µM for New York, 11 µM for all non-New York and 10.1 µM for California.
Variations were striking in the Cabernet sauvignon category. New York wine had an average of 8.3 µM in this category, with all non-New York Cabernet sauvignons at 3.7 µ, and California's at 1.7 µM. New York Cabernet sauvignon Francs averaged 8.6 µM, but no non-New York wines were analyzed for comparison in this category.
New York merlots averaged 6.5 µM compared with all non-New York merlots at 4.7 µM and California merlots at 5.3 µM.
New York wines also had the highest individual levels in each of these categories, with one Merlot at 10.7 µM, a Cabernet sauvignon at 19.2 µM, a pinot noir at 46.1 µM, a New York Cabernet Franc at 16.9 µM and a Lemberger at 15.3 µM.
"New York's relatively humid climate explains the higher concentrations of resveratrol in the wines," Creasy said. "Resveratrol is a natural fungicide, and the more humid the climate, the more is produced to combat mildew. During the long contact between the grape skins and the juice in producing red wines, the resveratrol is transferred into the wine."
The importance of the wine-making process in enhancing the resveratrol content was dramatically illustrated by Creasy's analysis of white wines -- eight from New York and five others -- which do not involve prolonged grape skin contact in the wine-making process and have negligible amounts of resveratrol. The New York white wines averaged 0.58 µM and the others, 0.6 µM.
The New York Wine and Grape Foundation, which gets matching funds from New York state, funded by Creasy's study.
"Every year wines are bound to have different amounts of resveratrol, and this makes it difficult for the consumer to figure out which kind of wine has more resveratrol over another," said Creasy. "So, the consumer is better off with a New York red than other reds, and the odds are better that the pinot has more resveratrol than cabernet. Consumers should buy a variety of wines, from different years and from different wineries."