March 12, 2012 -- Just one sugar-sweetened drink a day may be enough to raise a man’s risk for heart disease, a new study suggests.
Men who drank just one sugary drink a day had a 20% higher risk of heart disease than did non-drinkers, says researcher Frank Hu, MD, PhD, professor of nutrition and epidemiology at the Harvard School of Public Health.
"This study provides strong evidence that higher consumption of sugary beverages is an important risk factor for heart disease," he says. "Even moderate consumption -- one soda per day -- is associated with a 20% [increased] risk."
Hu's team followed nearly 43,000 men in the Health Professionals Follow-up Study. Previously, they conducted a similar study with women enrolled in the Nurses' Health Study. In that study, they also found a link between sugar-sweetened drinks and heart disease.
"In this one we tried to replicate the results in men," he tells WebMD. The results are very consistent, he says. "That is really enhancing the validity of the findings."
The team found a link, but that does not prove cause and effect.
The study is published in the journal Circulation.
The Sugar Association, an industry group, took exception with the findings, stressing that sugar is not the main culprit, but lifestyle. So did the American Beverage Association.
Sugar-Sweetened Drinks and Heart Disease: Study Details
Hu and his teams asked the men, aged 40 to 75 when the study started, to report their beverage-drinking habits. From January 1986 through December 2008, the men reported on their diet and other health habits every two years.
They provided a blood sample about halfway through the study.
During that time, there were 3,683 heart attacks.
Next, the researchers divided the men into four groups, depending on their sugar-sweetened drink habits. Such drinks included sodas, carbonated non-colas, fruit punches, lemonade, and other non-carbonated fruit drinks. The sugar-sweetened drinks studied did not include 100% fruit juices. The drinking habit groups were:
- No sugar-sweetened drinks
- Twice a month
- One to three times a week
- Nearly four times a week to nine per day -- an average of about 6.5 a week. (Half drank more, half less.)
Those in the last group were considered the daily drinkers.
Those in the daily group were 20% more likely to wind up with a heart attack than the non-drinkers, Hu found.
This was true even after accounting for other factors, such as age, smoking, exercise, alcohol drinks, diet quality, weight, and family history of heart disease.
They looked at the blood samples. Men who drank sugar-sweetened drinks daily had higher indicators for heart disease than the non-drinkers did.
Those who had a daily sugar-sweetened drink had higher levels of blood fats called triglycerides, a risk factor for heart disease. They had lower levels of HDL or "good" cholesterol, another risk factor.
Artificially Sweetened Drinks: Study Results
The men also reported how frequently they drank artificially sweetened drinks.
Hu didn’t find a link between drinks sweetened artificially (such as diet sodas) and heart disease or indicators of heart disease.
"But it doesn't mean diet soda is the best alternative," he says. "The data on diet soda is quite limited."
Explaining Sugar-Sweetened Beverages and Heart Disease
What can explain the link? "There are at least three things going on," Hu says.
"One is increased body weight, an immediate effect [of drinking sugar-sweetened beverages]. The second thing is blood lipids. It increases triglycerides and decreases HDL."
The drinks also increase inflammatory indicators linked with heart disease, he says, such as C-reactive protein. That has been found, he says, not only in his study but also in several others.
Sugar-Sweetened Drinks and Heart Disease: Perspectives
The findings are ''hardly a surprise," says Robert Lustig, MD, professor of clinical pediatrics at the University of California San Francisco, who has researched childhood and adult obesity. He reviewed the findings for WebMD.
In his own research, he says, he has found a link between sugar-sweetened drinks and high blood pressure, a risk factor for heart disease.
The new study provides some valuable information as to why the drinks and heart disease are linked, such as the inflammation effect, says Christina M. Shay, PhD, assistant professor at the University of Oklahoma, Lawton. In her own research, she has found a link between sugar-sweetened drinks and heart disease in women.
Sugar-Sweetened Drinks and Heart Disease: Industry Weigh-in
Charles Baker, PhD, chief science officer at the Sugar Association, takes issue with the findings.
Among the flaws, he says, is that the fourth group included a wide range. The intakes in that group ranged from 4.5 drinks a week to 7.5 a day. The researchers figured the average to be at 6.5 a week or about one a day. (Half drank more, half less.)
Baker says it was this ''data manipulation" that allowed the researchers to find the 20% increased risk.
In a statement, the American Beverage Association says, in part, that the men studied were nearly all white men of European descent. The findings, therefore, may not apply to the general population.
Other factors, such as stress, could have played a role, the statement says.
"The authors found an association between consuming sweetened beverages and [heart disease and stroke] risk, but this could have been the result of other lifestyle changes over the 22-year study period involving men 40 to 75 years of age," it adds.
Sugar-Sweetened Drinks and Heart Disease: Diet Advice
Those who love such drinks don’t have to give them up entirely, Hu says. "One or two a week, I don't think that's going to be a major problem," he says.
"We should treat soda as some kind of treat, not a regular event," he tells WebMD.
The American Heart Association recommends drinking no more than 450 calories of sugary drinks a week. That's fewer than three 12-ounce sugared drinks.
On a given day, about one of two people in the U.S. drinks a sugary drink, the CDC reports. One in 20 drinks more than four 12-ounce sugared beverages per day, it finds.