A recent Food Research International study determines whether the intake of sweetened beverages affects the degrees of salivary insulin, aspartame, alpha-amylase (AMI), and total protein (TP).

Study: Effect of sweetened beverages intake on salivary aspartame, insulin and alpha-amylase levels: A single-blind study. Image Credit: MamaMiaPL / Shutterstock.com

Background

The worldwide consumption of foods and beverages containing sweeteners is high, as many individuals innately prefer sweet taste. In truth, many individuals have replaced sugar with sweeteners attributable to their reduced caloric density as in comparison with sucrose. 

The World Health Organization (WHO) advises that non-sugar sweeteners mustn’t be used solely to regulate weight, as there may be an absence of evidence regarding their advantages for long-term use. Some studies have indicated that sweetener use causes the event of glucose intolerance in obese individuals. Thus, more research is required to know whether long-term sweetener use affects metabolism or causes opposed effects.

Common sweeteners

Common sweeteners added in foods and beverages include aspartame, cyclamate, and acesulfame potassium, all of that are synthetic products. Amongst these synthetic sweeteners, aspartame is essentially the most commercialized product globally. The most important components of aspartame are aspartate and phenylalanine, that are metabolized within the intestinal lumen.

Sodium cyclamate is supplemented with other sweeteners attributable to its residual taste. Although some countries have banned the usage of sodium cyclamate, others have permitted its use as a food additive at approved levels. Acesulfame potassium is an artificial compound with high sweetening power; nonetheless, this substance is just not metabolized.

In humans, the digestion of sugars starts within the oral cavity attributable to the presence of salivary alpha-amylase. The sweet taste is perceived through the stimulation of taste buds present within the oral cavity.

Subsequently, the sweet taste triggers many physiological processes, including increased salivary secretion and insulin secretion. Insulin secretion occurs in various phases, including the cephalic phase, which is related to an early increase in insulin levels in blood upon oral exposure to sweetness. 

It has been hypothesized that low/no-calorie sweeteners trigger sweet-tasting receptors, which ends up in insulin release, reduced blood glucose levels, and increased appetite. Salivary AMI is directly correlated with carbohydrate absorption and the glycemic index.

It will be significant to know the extent of secretion of salivary enzymes and hormones in response to artificial sweetener ingestion, as this may reflect digestion and carbohydrate metabolism.

In regards to the study

The present single-blinded randomized trial investigates the degrees of salivary aspartame, total protein, salivary AMI, and insulin levels after the ingestion of sweetened drinks. 

A complete of 15 healthy, normoglycemic young adults were included within the study cohort, 11 of whom were women. All candidates had healthy oral conditions, and none reported any underlying chronic conditions resembling diabetes, hypertension, and cancer. All participants were asked to stop the intake of sweeteners of their diets one week before the commencement of the trial and through the trial.

A complete of 5 sessions were attended by participants, during which they were asked to drink 200 mL of test drinks at each session. The five different test drinks utilized in this study were weight loss program soft drinks, regular soft drinks, mineral water with sweeteners, the identical products with low sucrose content of 0.02 g/mL, and water.

At every session, participants visited the laboratory without consuming food or drinks until the tip of all saliva collections. Five saliva samples were collected in each session, including before ingestion of the test drink, quarter-hour after ingestion of the test drink, after half-hour, after 60 minutes, and after 120 minutes, which were known as T0, T1, T2, T3, and T4, respectively.

Study findings

Aspartame was detected within the saliva of people who drank weight loss program soft drinks and water with sweeteners. A gradual rise in aspartame was observed at T4, thus indicating that aspartame stays within the digestive tract for a protracted period.

Although each the water with sweetener test drink and weight loss program soft drink contained the identical artificial sweetener concentrations, a greater aspartame level was recorded for individuals who drank the weight loss program soft drink. 

A correlation between aspartame concentration and insulin levels was observed just for weight loss program soft drink intake and never for sweetened water test-drink. The shortage of change in insulin levels after the consumption of sweetened water implies a faster metabolization as in comparison with weight loss program soft drinks. Importantly, all soft drinks had a lower pH than the sweetened water test drink, which could stimulate other physiological processes than sweet taste. 

Insulin levels rose after the consumption of each regular and weight loss program soft drinks. Although initially, each regular and weight loss program soft drinks exhibited similar rises in insulin levels, the regular soft drink led to a greater rise between T2 and T3 and subsequent decline between T3 and T4. An analogous trend was observed for glucose tolerance.

The sucrose solution didn’t result in any change in insulin levels over 120 minutes and remained stable over time. No change in alpha-amylase activity was observed after ingestion of sweet beverages.

Conclusions

A greater level of salivary aspartame was observed after the ingestion of weight loss program soft drinks than water with sweeteners. Moreover, higher salivary insulin levels were recorded after ingesting regular and weight loss program soft drinks in comparison with the control and low sucrose content drinks.