A diagnosis of diabetes comes with a long list of "don'ts." But new research suggests that coffee and tea probably shouldn't be off-limits because each may help prevent an early death.
Well, at least if you're a woman with diabetes, that is.
Men with diabetes didn't seem to reap the rewards of consuming caffeine in the new study.
The research found that women with diabetes who had up to one regular cup of coffee a day (100 milligrams of caffeine) were 51 percent less likely to die than women who consumed no caffeine during the 11-year study.
"As caffeine is consumed by more than 80 percent of the world's adult population, it is essential to understand the impact of this factor concerning cardiovascular, cancer and all-cause mortality," said study researcher Dr. Joao Sergio Neves, an endocrinology resident at Sao Joao Hospital Center in Porto, Portugal.
"Our study showed a significant inverse association between caffeine consumption and death from all causes in women with diabetes," said Neves.
"These results suggest that advising women with diabetes to drink more caffeine may reduce their mortality. This would represent a simple, clinically beneficial, and inexpensive option in women with diabetes," Neves said.
But he also pointed out that this observational study cannot prove a direct cause-and-effect link; it only found an association between caffeine consumption and the risk of dying.
"Further studies, ideally randomized clinical trials, are needed to confirm this benefit," Neves said.
The study authors reviewed information collected in a U.S. study that included more than 3,000 people with diabetes -- both type 1 and type 2 diabetes. The data was collected between 1999 and 2010.
Besides gathering general health information, the researchers asked study participants about their caffeine intake from coffee, tea and soft drinks.
Over the course of the study, just over 600 people died.
The researchers found that the more coffee a woman with diabetes consumed, the lower the risk of death. Women who had 100 to 200 milligrams of caffeine a day in coffee had a 57 percent lower risk of death compared to women who had no caffeine. For women who had more than 200 milligrams daily in coffee (two cups), the risk of death was reduced by 66 percent.
The researchers adjusted the data to account for factors including race, age, education level, income, smoking, weight, alcohol intake, blood pressure and diabetic kidney disease.
The study found a different benefit from drinking caffeine in tea -- an 80 percent lower risk of dying from cancer for women who drank the most caffeine from tea compared to those who drank none. But the authors noted there was only a small number of tea drinkers in the study.
Neves said the researchers aren't sure why no benefit was seen for men with diabetes.
"A possible explanation is the biological differences between sexes, dependent of both hormonal and non-hormonal factors, mainly on the cardiovascular system level," Neves said. "Still, we cannot exclude that the sample of our study may have been underpowered to detect a smaller benefit of caffeine consumption among men."
And what of coffee's benefit for survival? How might the beverage reduce a woman's risk of dying?
"The observed benefits may be directly related to caffeine or to other components present in caffeine-containing beverages," Neves suggested.
Previous studies have shown that consumption of coffee or tea is associated with improved insulin sensitivity and better control of blood sugar after eating in patients with diabetes, Neves said. "Furthermore, the minerals, phytochemicals and antioxidants present in the caffeine-containing beverages may also contribute to the benefit seen in women's mortality," he added.
Dr. Robert Courgi is an endocrinologist and diabetes expert at Southside Hospital in Bay Shore, N.Y.
"Other studies have found caffeine to be beneficial, and here is more evidence to confirm it," said Courgi, who wasn't involved with the study.
And, like the study authors, Courgi said, "Further prospective studies should be performed to prove this supposed benefit of caffeine."
Neves is scheduled to present the study findings Thursday at the European Association for the Study of Diabetes, in Lisbon, Portugal. Findings presented at meetings are generally viewed as preliminary until they're published in a peer-reviewed journal.