COMPLICATED LINK BETWEEN DIET DRINKS AND HEALTH

Several studies have found that people who regularly consume diet beverages are more likely to have risk factors for chronic diseases (such as heart disease and diabetes), than people who do not drink diet beverages. For example, a recent study tracking 2,564 seniors over time found that those who drank diet soda regularly were 44% more likely to suffer a heart attack or stroke. Still, the researchers also noted that persons reporting daily diet soda use also tended to be heavier, and have less healthy lifestyles.  In this report and other observational studies with similar findings, the association between poor health and regular diet soda consumption does not mean that the actual diet drinks cause health problems.  It is possible that those consuming diet soda also tend to have other unhealthy habits such as poor diet or inactivity. 

An interesting recent observational study that tracked diet soda as well as dietary intake overall concluded that while a small amount of disease risk may be due to diet drink consumption, overall diet quality makes a much bigger difference in chronic disease risk.  This investigation, lead by Dr. Kiyah Duffey, examined data on more than 4,000 Americans taking part in a long-term study of heart health. Participants were ages 18-30 when the study began in the mid-1980s.  Over the next 20 years, 827 study participants developed metabolic syndrome -- a cluster of risk factors for heart problems and diabetes including extra weight around the waist, unhealthy cholesterol levels, high blood pressure and elevated blood sugar.  The researchers found that the lowest risk of metabolic syndrome, 18%, was seen among people who drank no diet beverages and stuck to a "prudent" diet -- one rich in fruits, vegetables, whole grains and fish and moderate in meat and added sugars.  Meanwhile, people who also ate a prudent diet but did drink diet beverages had a modestly higher rate of metabolic syndrome at 20%. Among participants who followed a typical “Western” diet high in meat, refined grain products, and added sugars, whether they drank diet soda or not, their rate of metabolic syndrome was 32%. "I really think it's overall diet that's matters.  It's very important to have a healthy balanced diet," Dr. Duffey said.

It is not clear how diet drink consumption might lead to higher rates of chronic disease.  There is some evidence that frequent consumption of sweet-tasting foods stimulates overall appetite, especially for sweets so that those who drink diet soda also might consume more calories or sugar from other foods.

There is also a body of research indicating that diet drinks are a useful tool in reducing consumption of caloric sweetened drinks and that when persons switch from regular soda consumption to diet soda, their weight and chronic disease risk factors tend to improve.  For example, a recent randomized controlled trial examined weight and cardiometabolic risk factors after six months during which the participants in one group were asked to replace at least 2 regular sweetened drinks with diet drinks and participants in another group were asked to replace at least 2 regular sweetened drinks with water. At six months, while both groups demonstrated improvements in risk factors, there were significantly greater improvements noted in systolic blood pressure, fasting glucose, and weight change compared to the water group.  It appears this may be due to better adherence to sweetened drink replacement in the diet drink group than in the water group.  Participants in the diet beverage group were able to cut down an average of 218 drink calories per day, while those in the water group cut an average of 148.  Thus, studies like this one, indicate that among those who regularly consume sweetened beverages, replacing them with diet drinks may be a more realistic way to reduce unhealthy sweetened drink consumption. Given that approximately 60% of U.S. adults report drinking sugar-sweetened beverages totaling an average of 300 calories per day, finding viable ways to reduce consumption of sweetened drinks is imperative. 

What to do:  Because frequent sweetened drink consumption including juice, soda, and sweet tea is associated with weight gain and poorer long-term health, try to avoid their consumption.   Whether or not diet drinks negatively impact health remains debated.  If you are able to replace sweetened drinks with water, seltzer, or herbal tea, these are likely you best choice.  Still, when really craving a sweet tasting drink, having a diet drink appears to be a better option than having the regular drink. 

SOURCES: Available at http://bit.ly/H0B6aZ. Report adapted from articles available at http://www.nlm.nih.gov/medlineplus/news/fullstory_123495.html,  http://www.nlm.nih.gov/medlineplus/news/fullstory_123495.html, http://www.nlm.nih.gov/medlineplus/news/fullstory_122137.html