Stevenson, though, says that because resveratrol is sensitive to air and light, the process of extracting it from plants and then purifying it may impair its effectiveness. “Beer’s actually this really ideal transport vessel for these light and air-sensitive pharmacological products,” he says.
The idea of brewing resveratrol beer is “potentially good,” says Leonard Guarente, a professor at MIT who’s studied the effects of resveratrol, but the BioBeer team must prove that it’s bioactive.
The students plan to test their BioBeer on fruit flies to confirm that it extends their life spans. Researchers have shown that resveratrol gives flies, mice, and worms longer, healthier lives, mimicking the effects of a very low-calorie diet. Resveratrol is also being tested as a treatment for type 2 diabetes.
Resveratrol is found in modest amounts in peanuts and some berries, including cranberries and blueberries, but it is more plentiful in the skins of grapes. When grapes are fermented to produce red wine, the skins are left on, but they’re removed earlier in the process of producing white wine–hence the greater resveratrol concentration in red wine.
The Rice University team has engineered yeasts to produce resveratrol, and they’re about to brew their first batch of BioBeer.
Resveratrol shouldn’t affect the taste of the beer, Silberg says, but another biological product of the yeast might. One of the enzymes that the students added to the yeast not only catalyzes the first step in the production of resveratrol but also transforms phenylalanine into cinnamic acid. Cinnamic acid has a honeyed, floral taste, which “sounds like a plus for flavor,” Stevenson says. Like five of the six team members, though, Stevenson isn’t old enough to legally sample his BioBeer.
Mark Leid, a professor in the Department of Pharmaceutical Sciences at Oregon State University, wonders whether the BioBeer will contain enough resveratrol to have health benefits when consumed in moderate amounts. That remains to be seen, Stevenson says, but he adds that the bioengineered yeast could be further modified to optimize resveratrol production.
“The amount in red wine’s actually not that much compared to what might be possible with this process,” Segall-Shapiro says.
At the moment, Stevenson says, the yeast does not contain a gene that actively exports resveratrol out of the cell. Some will diffuse out of the cell on its own, but in the short term, he says, the beers that impart the greatest health benefits could be unfiltered brews like Hefeweizens, which are clouded by yeast that drinkers swallow whole.
Although plenty of people already pop resveratrol pills, “there are a lot of things that need to be done before we put resveratrol in foods or we put it in a pill,” de Cabo says. “There are a number of things we don’t know about resveratrol.”
Besides, he says, “we’re running on hope that some of the things we’ve seen in the mouse studies will replicate in humans.”