- NewScientist.com news service
- Ewen Callaway
White wine lovers can feel a little less guilty about their habit. New research suggests that white varieties may offer similar heart benefits to red wines.
Rats that were fed white wine as part of their diet suffered less heart damage during cardiac arrest, compared to animals fed only water or grain alcohol. These benefits were similar to animals that ingested a red wine or its wonder ingredient found only in grape skin, resveratrol.
White wine, made from the pulp of the grape but not the skin, contains no resveratrol, which led many to pin the so-called "French paradox" – high fat intake but low rates of heart disease – on moderate consumption of red wines.
Not just reds, says Dipak Das, a molecular biologist at the University of Connecticut School of Medicine in Farmington. "The flesh of the grape can do the same job as the skin."
He and colleagues gave lab rats measured doses – roughly equivalent to one or two glasses a day – of red or white Italian wines, while others received comparable doses of different chemical ingredients thought to underlie the health benefits of wine, called polyphenols.
In lab rats that suffered heart attacks, the animals that received wine or polyphenols experienced less heart damage, compared to rats fed water or straight liquor. Their blood pressure and aortic blood flow plummeted less drastically as well.
Molecular tests of heart cells suggest that white wine protects the cell's powerhouses – mitochondria. Damage to these structures caused by lack of oxygen and nutrients can send cells down one-way path to suicide, or apoptosis.
The mitochondria from wine-drinking rats looked to be in better shape and fewer of their cardiac cells entered apoptosis. This was also the case for rats that got polyphenols, including resveratrol from red wine, and tyrosol and hydroxytyrosol from whites.
A look at the structure of the three chemicals' offers one possible reason why, Das says. While not identical, the trio have enough similarities that they could activate some of the same cellular reactions.
Das's data provide compelling evidence that white wine protects laboratory rats from the effects of a heart attack, says Lionel Opie, director of Hatter Institute for Cardiology Research in Cape Town, South Africa.
However, he points out that human heart attacks occur due to blood clots in diseased arteries and not necessarily because of mitochondrial failure. More relevant experiments in dogs showed a benefit for red wine, but not white, Opie adds.
But Das expects similar studies to soon prove white wine's worth. "We can safely say that one to two glasses of white wine per day works exactly like red wine," he says.
Das blames white wine's late inclusion to the French paradox on the phenomenon's original medical report in 1992, as well as researcher's single-minded focus on resveratrol.
And while the evidence is still scant, an "English paradox" may yet emerge. "Beer is also cardioprotective," Das says.