A prospective study in middle-aged and older adults has linked consumption of even modest daily amounts of sugary drinks with adverse changes in lipid concentrations that represent risk factors for cardiovascular disease (CVD).
The study, led by scientists at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University (HNRCA), found that adults who drank at least one sugar-sweetened beverage daily during the most recent period of follow-up, which averaged about four years before the assessment of lipid levels, had a 98% higher chance of developing low high density lipoprotein cholesterol (HDL-), which is thought of as ‘good’ cholesterol, and a 53% higher chance of developing high triglycerides, when compared with individuals who only occasionally consumed sugary drinks. The results were similar when the investigators considered the long-term intake of sugary beverages during a follow-up time of about 12 years. In contrast, regular consumption of fruit juice (FJ) wasn’t linked with any adverse changes in lipoprotein concentrations or the development of dyslipidemia.
“The results suggest that high intake of drinks with added sugar, such as soda, lemonade or fruit punch, may influence risk for dyslipidemia as we age,” said Nicola McKeown, PhD, a nutritional epidemiologist at the HNRCA. “One dietary strategy to help maintain healthier blood cholesterol and triglyceride levels may be to avoid drinks with added sugars.” McKeown is corresponding author of the team’s published paper in the Journal of the American Heart Association.
“Our findings show that what we put in our glass may contribute to greater risk of cardiovascular disease via worsening of lipid levels,” she added. “Managing blood cholesterol and triglyceride levels is an important goal and a promising strategy for preventing heart attack and stroke … We are better off quenching our thirst with water.” The team reports the results of its study in a paper titled, “Beverage Consumption and Longitudinal Changes in Lipoprotein Concentrations and Incident Dyslipidemia in US Adults: The Framingham Heart Study.”
An estimated 40- 50% of adults in the US can be classified as having dyslipidemia, which is characterized by high triglyceride levels, high low-density lipoprotein cholesterol (LDL-C), and/or low high-density lipoprotein cholesterol (HDL-C) concentrations, which predisposes them to increased risk for cardiovascular disease (CVD), the authors wrote. Previous studies have indicated that consuming added sugars in the form of sugar-sweetened beverages (SSBs) represents an increased cardiovascular disease risk. Drinks such as sodas, sports drinks, pre-sweetened coffees and teas, and fruit-flavored drinks typically represent the largest source of added sugars for Americans, and past studies have found that SSB consumption is adversely linked to lipid concentrations.. “One potential mechanism by which SSBs may increase the risk for CVD is through the development of dyslipidemia,” the authors further noted. “Animal and human intervention trials suggest that consumption of large amounts of sugar, particularly those high in fructose, can rapidly induce dyslipidemia.”
The HNRCA-led researchers carried out a prospective study to investigate any association between SSB, low-calorie sweetened beverages (LCSBs) and FJ consumption, and changes in triglyceride, LDL-C, HDL-C, and non-HDL-C levels in the Framingham Offspring Study and GEN3 (Generation 3) cohorts .”We hypothesized that greater SSB consumption would association with unfavourable longitudinal changes in lipoprotein concentrations and incident lipidemia, and to a greater extent than LCSBs and FJs,” they stated.
To determine any association between sugary drinks and triglyceride and cholesterol levels, the researchers evaluated the observational medical data of up to 5,924 participants from the Offspring and Generation 3 cohorts of the Framingham Heart Study, who were followed for an average of 12.5 years between 1991 and 2014. The Offspring cohort of the Framingham Heart Study includes the children of original participants in the Framingham Heart Study, and the Generation 3 cohort includes grandchildren of the original participants in the Framingham Heart Study.
For the newly reported work, one serving of a beverage was were defined as: 12 ounces of sugary drinks, such as sodas, fruit-flavored drinks, sports drinks, presweetened coffees and teas; 12 ounces of low-calorie sweetened beverages, including naturally and artificially sweetened diet sodas or other flavored drinks; or 8 ounces of 100% fruit juices, including orange, apple, grapefruit and other juices derived from whole fruits with no added sugars. Study participants were classified into five groups according to how often they drank the different beverage types, ranging from high to low intake.
The investigators assessed how the different drink types and their consumption levels correlated with changes in cholesterol and triglyceride levels over time. The study participants were examined at intervals of four years, on average, and followed for about 12 years. In their statistical analysis, the researchers adjusted for other factors known to influence cholesterol and triglyceride concentrations, such as obesity, overall diet quality, physical activity, alcohol intake, and the use of cholesterol-lowering drugs.
They found that drinking more than 12 ounces of SSB per day was associated with a 53% higher incidence of high triglycerides and a 98% higher incidence of low HDL cholesterol, compared with drinking less than one serving per month. Interestingly, drinking low-calorie sweetened beverages did not appear to be associated with increased dyslipidemia. People who drank up to 12 ounces of 100% fruit juice per day also showed no adverse changes in cholesterol or dyslipidemia, although the researchers acknowledge that further research will be needed to confirm this finding.
There were also trends towards adverse changes in HDL cholesterol and triglyceride levels among younger adults – averaging in their 40s – who drank a lot of sugary beverages. “With these younger participants, we did see unfavorable changes, but they were likely too young during the short follow-up period to know if they would eventually develop dyslipidemia,” said first author Danielle Haslam. “Our findings contribute to the mounting evidence that sugary drinks should be avoided to help maintain long-term health.” Haslam was a doctoral student at the Gerald J. and Dorothy R. Friedman School of Nutrition Science and Policy at Tufts University, working in the nutritional epidemiology program at the time of the study.
“Our results support the recommendations to limit sugar sweetened beverage intake and suggest that dyslipidemia may be one mechanistic pathway whereby sugar-sweetened beverage intake may increase cardiovascular disease risk,” the authors concluded. “Dietary patterns low in sugar-sweetened beverages may contribute to maintenance of favorable plasma lipoprotein profiles … These findings are consistent with current recommendations to limit SSB consumption and emphasize the need for further research to inform recommendations related to LCSB and FJ consumption.”
The scientists acknowledged that there were limitations to their study, and as an observational design, the investigation doesn’t reflect a causal relationship between sugary drink consumption and adverse changes to cholesterol and triglyceride levels. Nevertheless, McKeown commented, “Reducing the number of or eliminating sugary drink consumption may be one strategy that could help people keep their triglyceride and HDL cholesterol at healthier levels … And, while our study didn’t find negative consequences on blood lipids from drinking low-calorie sweetened drinks, there may be health consequences of consuming these beverages on other risk factors … The emerging research on long-term consumption of diet soda on health is inconclusive, so it is prudent to say diet drinks should only be an occasional indulgence. As for 100% fruit juice, best to limit consumption and consume whole fruits when possible, as recommended by the 2015-2020 Dietary Guidelines for Americans.” The American Heart Association recommends people eliminate sugary drink consumption to improve heart health and to reduce the risk of cardiovascular disease.
“For some time, we have known sugary drinks can have a negative effect on Americans’ health status, yet the assumption for many is that they only contribute to weight gain,” said Eduardo Sanchez, MD, MPH, chief medical officer for prevention and chief of the Center for Health Metrics and Evaluation at the American Heart Association. “This research reinforces our understanding of the potential negative impact sugary drinks have on blood cholesterol, which increases heart disease risk. It is yet one more reason for all of us to cut back on sodas and other sugar-sweetened beverages.”