A Single Drink a Day May Cause High Blood Pressure
New large study contradicts previous research finding that moderate alcohol consumption may be heart healthy.
For anyone who believed that a glass of wine a day is good for your heart, new research presented last month at the American College of Cardiology’s (ACC) Annual conference may be hard to swallow.
A study of more than 17,000 U.S. adults showed that as little as a drink a day may contribute significantly to high blood pressure (hypertension). This investigation differs from past research, according to study authors, in that it specifically evaluated the link between hypertension and moderate drinking rather than the link between alcohol and heart disease.
“Our results demonstrate that even if you only drink a moderate amount of alcohol, ask your provider to check your blood pressure at each visit,” said Amer Aladin, MD, lead author of the study and a cardiology fellow at Wake Forest Baptist Health in Winston-Salem, North Carolina. “If your blood pressure is elevated you should take appropriate measures to reduce it, which possibly means reducing your alcohol consumption.”
The American Heart Association warns that high blood pressure increases your risk of heart attack and stroke.
Understanding Blood Pressure Levels
Research participants provided details about their drinking habits via a questionnaire that was part of the Centers for Disease Control and Prevention's (CDC) National Health and Nutrition Examination Survey.
The study defined moderate drinkers as those having 7 to 13 drinks per week, while heavy drinkers downed 14 or more drinks on a weekly basis.
Investigators measured blood pressure during in-home interviews and at a mobile examination center. Pressure is gauged in millimeters of mercury, or mmHg. The top number (systolic) represents how much pressure is pushing against artery walls as the heart beats, and the bottom number (diastolic) represents pressure when the heart rests between beats. Readings were categorized according to American Heart Association standards.
Based on their findings, study authors determined that the likelihood of having elevated high blood pressure was on average 19 percent greater among moderate drinkers and 44 percent higher for the heavy drinkers compared with those who never drank.
Compared with the never-drinkers, moderate drinkers had 53 percent higher odds of having stage 1 hypertension and 100 percent greater odds for stage 2 hypertension.
Risks were higher for heavy drinkers; they faced a 69 percent greater chance of developing stage 1 hypertension and 140 percent greater chance for stage 2 hypertension compared with those who totally avoid alcohol.
Overall, the average blood pressure was about 109/67 mmHg among never-drinkers, 128/79 mmHg among moderate drinkers, and 153/82 mmHg among heavy drinkers.
The results took into account other factors linked to hypertension, such as age, sex, race, income, and cardiovascular risks separate from alcohol consumption.
Why Does Alcohol Stress the Heart?
A variety of factors may explain alcohol’s impact on the heart, according to research scientists.
“Alcohol increases appetite and is itself very energy-dense, so drinking often leads to greater caloric intake overall,” said Dr. Aladin.
With more calories consumed, weight gain can follow, which is a well-established factor in raising blood pressure.
In addition, people who drink a lot may be more likely to eat unhealthy foods and exercise less. Alcohol consumption may also increase inflammation and oxidative stress in the body, which may have a negative effect on heart health.
Unexpected Results and Study Limitations
Sarah Samaan, MD, a cardiologist with Baylor Scott & White Legacy Heart Center in Plano, Texas, found the findings slightly surprising.
“It's not clear at what intervals the drinks were consumed,” says Dr. Samaan. “For some people, those drinks may all be consumed on the weekend, and we know that binge drinking raises blood pressure, even if it's just a couple of days per week. Other studies have fairly conclusively found a link between heavier drinking and high blood pressure.”
Because one drink per night may have a very different effect on blood pressure compared with four drinks two nights per week, Samann would like to see more research on the daily frequency of alcohol intake.
In addition, she notes that it’s uncertain how food choices and other behaviors might be affecting blood pressure outcomes.
As an observational study relying on self-reported alcohol use, the study is somewhat limited, according to Salim Virani, MD, a staff cardiologist at the Michael E. DeBakey VA Medical Center in Houston and chair of the ACC’s Prevention Section and Leadership Council.
“We know that patients may underreport their use of alcohol, so they may be using more alcohol than what they stated on the questionnaires,” says Dr. Virani.
Samaan adds that more research is needed before strong recommendations can be made.
“The takeaway is that if you are suffering from high blood pressure, take a look at your alcohol consumption,” she says. “If you drink regularly, cutting back to just a few times per week may make a significant difference.”