June 30, 2011 (San Diego) -- Drinking about four or more 8-ounce glasses of water a day may protect against the development of high blood sugar (hyperglycemia), French researchers report.
In a study of 3,615 men and women with normal blood sugar levels at the start of the study, those who reported that they drank more than 34 ounces of water a day were 21% less likely to develop hyperglycemia over the next nine years than those who said they drank 16 ounces or less daily.
The analysis took into account other factors that can affect the risk of high blood sugar, including sex, age, weight, and physical activity, as well as consumption of beer, sugary drinks, and wine.
Still, the study doesn't prove cause and effect. People who drink more water could share some unmeasured factor that accounts for the association between drinking more water and lower risk of high blood sugar, says researcher Ronan Roussel, MD, PhD, professor of medicine at the Hospital Bichat in Paris.
"But if confirmed, this is another good reason to drink plenty of water," he tells WebMD.
The findings were presented here at the annual meeting of the American Diabetes Association.
About 79 million Americans have prediabetes, a condition in which blood sugar levels are higher than normal but not high enough to result in a diagnosis of diabetes, according to the CDC. It raises the risk of developing type 2 diabetes, heart disease, and stroke. An additional 26 million have diabetes, the CDC says.
The Link Between Water and Hyperglycemia
Roussel notes that recent research indicates an association between the hormone vasopressin, which regulates water in the body, and diabetes.
Despite the known influence of water intake on vasopressin secretion, no study has investigated a possible association between drinking water and risk of high blood sugar, he says.
Participants in the new study were offered health examinations every three years, including a self-administered questionnaire asking how much water, wine, beer-cider, and sweet drinks they drank a day. Blood sugar levels were measured at the study's onset and about nine years later.
Over the course of the study, 565 people developed hyperglycemia.
The next step, according to Roussel, should be a study of people who say they don't drink a lot of water, half of whom agree to increase their intake over a certain period. That would help confirm that drinking more water helps stave off high blood sugar, he says.
James R Gavin III, MD, PhD, clinical professor of medicine at Emory University School of Medicine in Atlanta, tells WebMD that more basic research into the link between drinking water and hyperglycemia is needed.
"Not drinking enough water could be similar to what we see in people who consume a lot of cholesterol," says Gavin, who is also chair of the Partnership for a Healthier America, an initiative to fight childhood obesity.
A lot of cholesterol and fat in the diet may make some people more susceptible to type 2 diabetes, he says. It contributes to the development of atherosclerosis, or hardening of the arteries, that is commonly seen in people with the condition, he says.
"Insufficient fluid intake may also influence susceptibility to diabetes," Gavin says.
These findings were presented at a medical conference. They should be considered preliminary as they have not yet undergone the "peer review" process, in which outside experts scrutinize the data prior to publication in a medical journal.