Sugar-sweetened beverages (SSB) include commonly consumed products such as soda, sports drinks, and energy drinks; coffee, tea, and water with added sugars; and some fruit juices, although not all nutrition experts agree on fruit juice’s inclusion as an SSB. While the consumption of SSBs has declined in recent decades, they remain a leading contributor to sugar intake among people living in the United States.
While the over-consumption of sugar from any source is harmful for health, SSBs present a physiologically unique risk to health due to a converging set of factors. Because they contain no supporting food matrix to slow absorption, SSBs are rapidly absorbed by the gut and cause blood sugar spikes. Sugars from fruits and vegetables are packaged with a matrix of fiber and micronutrients that reduce the rate of digestion. This slow digestion and absorption reduces blood sugar spikes and supports better glycemic control. Additionally, many SSBs exceed the recommended maximum daily added sugar intake of 25 grams in a single serving and may be consumed more rapidly than solid sources of dietary added sugar. These factors - matrix and dose - make SSB unique from other highly processed foods.
Previous evidence supports a relationship between the over-consumption of SSBs and multiple chronic diseases, such as: - insulin resistance and type 2 diabetes, - obesity, - cardiovascular disease, - kidney disease, - and gout.
Below is a selection of summaries from current research investigating the effects of sugar-sweetened beverage consumption on health.
Consumption of a single SSB induces acute endothelial dysfunction – the inability of the cells that line the blood vessels to maintain the right vascular rigidity in order to regulate blood flow, often due to inflammation. In one study, 22 healthy participants who were not regular exercisers consumed three SSB per day for seven days. The beverages contained 75 grams of glucose – roughly equivalent to the amount provided in a typical, large-sized non-diet soft drink. They ate their regular diet throughout the study period. On five of the seven days, half of the participants engaged in a 45-minute supervised exercise protocol on an exercise bike at 60 to 65 percent of their maximal heart rate. The investigators measured the participants' flow-mediated dilation, an indication of how wide the brachial artery dilates when blood flow is restricted in the arm.
One week of SSB consumption caused endothelial dysfunction and reduced flow-mediated dilation in the non-exercising group, compared to their baseline function. However, the participants who engaged in regular aerobic exercise did not experience impairments in endothelial function, suggesting that exercise offsets some of the deleterious effects of regular sugar consumption.
Dyslipidemia, a condition in which blood levels of lipids (such as cholesterol or triglycerides) are abnormal, is a primary risk factor for cardiovascular disease. Most dyslipidemias are characterized by high plasma cholesterol or triglycerides (or both), or low HDL cholesterol. In order to determine the long-term effects of SSB consumption on cardiovascular disease, researchers reviewed data from more than 6,700 participants of the Framingham Heart Study. At various time points during the study, participants provided complete medical histories, underwent physical exams, and completed lab tests to assess total cholesterol, HDL cholesterol, and triglyceride levels. They also completed questionnaires about their lifestyles and diet, including beverage intake. Participants were tracked for an average of 12.5 years.
The data revealed that consuming more than 12 ounces of SSBs per day increased the risk of having high triglycerides by 53 percent and having low HDL cholesterol by 98 percent. Consuming low-calorie sweetened beverages (e.g., “diet” drinks) or up to 12 ounces of 100 percent fruit juice was not associated with dyslipidemia. These findings suggest that consumption of SSBs increases the risk of dyslipidemia and underscores the role of nutrition in reducing risk factors that contribute to cardiovascular disease.
Regular consumption of high glycemic foods (e.g., soda, candy, pastries) may lead to insulin resistance, type 2 diabetes, and obesity. Low-calorie sweeteners (i.e., artificial sweeteners, non-nutritive sweeteners) such as allulose have a low glycemic index and can be used in place of sugar to reduce the intake of calories and high-glycemic carbohydrates; however, the effects of allulose in addition to sugar require further investigation. Authors of one report recruited 30 participants without type 2 diabetes and asked them to follow an individualized diet plan that provided 50 to 65 percent of calories from carbohydrates for up to eight weeks. Participants completed five study visits with one to two weeks between visits. At each visit, the researchers gave participants a beverage containing 50 grams of fructose (the amount in about 16 ounces of sugar-sweetened soda) with escalating doses of allulose (0, 2.5, 5, 7.5, or 10 grams). They measured glucose and insulin levels in the blood 0, 30, 60, 90, and 120 minutes after beverage consumption.
Allulose consumption reduced plasma glucose levels among participants in a dose-dependent manner, meaning as the dose of allulose increased from 0 to 10 grams, glucose levels at each time point decreased. The relationship between allulose and lower glucose levels was statistically significant at the 30-minute time point when either 7.5 or 10 grams of allulose was added to the fructose beverage. Compared to consuming a fructose beverage with no added allulose, the 10-gram dose of allulose also significantly decreased insulin levels 30 minutes after beverage consumption. Additional research is needed to understand the molecular mechanisms that underlie these results; however, these results suggest allulose may reduce the body’s glycemic response to SSB without reducing sweetness.
Epidemiological evidence demonstrates higher serum testosterone levels in males without diabetes compared to males with diabetes. Previous clinical research has reported a relationship between SSB consumption and decreased sperm motility and fertility; however, its relationship with testosterone has not yet been demonstrated. Authors of one report reviewed data from the 2011-2012 National Health and Nutrition Examination Survey, a large-scale survey research project that tracks the health and nutrition of adults and children in the United States over time. Research staff for this project interview participants to collect dietary and demographic information and administer medical, dental, and laboratory tests to collect physiologic measures.
The researchers evaluated data from a sample group of 545 younger men between the ages 20 and 39 years because this is the period when fertility is highest. They categorized participants into four levels of SSB consumption, with participants in the lowest category consuming 137 calories of SSB or less per day and those in the highest category consuming 442 calories or more per day. Participants in the highest category of SSB consumption were more than twice as likely to have low serum testosterone. After taking into account other factors, including age, race/ethnicity, poverty/income, tobacco and alcohol consumption, and physical activity, the authors also found that participants with overweight and obesity were nearly four times more likely to have low serum testosterone compared to lean males, independent of SSB consumption.
This report demonstrates that SSB consumption and higher body mass index were both associated with lower testosterone levels in males. These associations were independent of each other and not due to other demographic and lifestyle factors.
Consumption of a Western diet pattern, which commonly includes SSBs, is associated with increased colon cancer risk. One team of investigators reviewed data from 95,000 participants of the Nurses Health Study II, an observational study comprised of female nurses between the ages of 25 and 42 years of age living in the United States between 1991 and 2015. Every two years, participants provide information about their demographics, lifestyles, and overall health, including whether they have been diagnosed with colorectal cancer. Every four years, they completed food frequency questionnaires that included questions about their dietary patterns. A subset of approximately 41,000 participants provided information about their beverage intake during their teen years.
The authors found that 109 participants developed early onset colorectal cancer. Participants who drank two or more servings of SSBs per day during adulthood were more than twice as likely to develop early onset colorectal cancer than participants who consumed less than one serving per week. This risk was dose-dependent, with a 16 percent higher risk per additional daily beverage. Participants who consumed SSBs during their teen years had a 32 percent greater risk for each additional daily serving. Replacing SSBs with milk or beverages containing non-nutritive sweeteners decreased participants’ risk of early onset colorectal cancer by 17 to 36 percent. These findings suggest that consuming SSBs during adolescence and adulthood markedly increases risk of developing colorectal cancer.
A: Drinking sugar-sweetened beverages can suppress the hormone cortisol and stress responses in the brain, which can drive people to consume more than they should.
Q: Do the same risks of refined sugar apply to unrefined sweeteners like coconut sugar, maple syrup, monk fruit or dried fruit (e.g. dates)?
A: Unrefined sweeteners are more likely to contain fiber and micronutrients (i.e., vitamins, minerals, phytochemicals), which slow the absorption of sugar and blunt the glycemic response.
Q: Are non-nutritive (i.e., artificial) sweeteners a good alternative to sugar?
A: This study reports the effects of different non-caloric artificial sweeteners (NAS) have on microbiome of animals. NAS do modify the microbiome but not in a way that is predictable and it seems that differences in NAS cause different effects. It is true that there are several studies showing that non-caloric artificial sweeteners lead to insulin resistance. This is partly because artificial sweeteners stimulate sweet receptors in the mouth that initiates a release of insulin. Because it still stimulates insulin that will increase insulin resistance in the long-run. Another reason is that it could be due to the change in the microbiome itself.
Long-term data of non-caloric artificial sweeteners is very mixed. 1) It is hard to differentiate whether the non-caloric artificial sweetener causes the poor health outcomes or if people are resorting to non-caloric artificial sweeteners because they have poor health outcomes (chicken and the egg situation). Also study results differ based off what you are comparing the artificial sweeteners to. When compared to water you are more likely to have significant negative effects. When compared to sugar you are more likely to have no negative effects observed. For now I think it is safe to say that artificial sweeteners have negative health effects but may be not as bad as refined sugar.