Effects of aspartame-, monk fruit-, stevia- and sucrose-sweetened beverages on postprandial glucose, insulin and energy intake.

BACKGROUND: Substituting sweeteners with non-nutritive sweeteners (NNS) may aid in glycaemic control and body weight management. Limited studies have investigated energy compensation, glycaemic and insulinaemic responses to artificial and natural NNS. OBJECTIVES: This study compared the effects of consuming NNS (artificial versus natural) and sucrose (65 g) on energy intake, blood glucose and insulin responses. METHODS: Thirty healthy male subjects took part in this randomised, crossover study with four treatments: aspartame-, monk fruit-, stevia- and sucrose-sweetened beverages. On each test day, participants were asked to consume a standardised breakfast in the morning, and they were provided with test beverage as a preload in mid-morning and ad libitum lunch was provided an hour after test beverage consumption. Blood glucose and insulin concentrations were measured every 15 min within the first hour of preload consumption and every 30 min for the subsequent 2 h. Participants left the study site 3 h after preload consumption and completed a food diary for the rest of the day. RESULTS: Ad libitum lunch intake was significantly higher for the NNS treatments compared with sucrose (P=0.010). The energy 'saved' from replacing sucrose with NNS was fully compensated for at subsequent meals; hence, no difference in total daily energy intake was found between the treatments (P=0.831). The sucrose-sweetened beverage led to large spikes in blood glucose and insulin responses within the first hour, whereas these responses were higher for all three NNS beverages following the test lunch. Thus, there were no differences in total area under the curve (AUC) for glucose (P=0.960) and insulin (P=0.216) over 3 h between the four test beverages. CONCLUSIONS: The consumption of calorie-free beverages sweetened with artificial and natural NNS have minimal influences on total daily energy intake, postprandial glucose and insulin compared with a sucrose-sweetened beverage.

Steviol glycosides in purified stevia leaf extract sharing the same metabolic fate.

The safety of steviol glycosides is based on data available on several individual steviol glycosides and on the terminal absorbed metabolite, steviol. Many more steviol glycosides have been identified, but are not yet included in regulatory assessments. Demonstration that these glycosides share the same metabolic fate would indicate applicability of the same regulatory paradigm. In vitro incubation assays with pooled human fecal homogenates, using rebaudiosides A, B, C, D, E, F and M, as well as steviolbioside and dulcoside A, at two concentrations over 24-48 h, were conducted to assess the metabolic fate of various steviol glycoside classes and to demonstrate that likely all steviol glycosides are metabolized to steviol. The data show that glycosidic side chains containing glucose, rhamnose, xylose, fructose and deoxy-glucose, including combinations of α(1-2), ß-1, ß(1-2), ß(1-3), and ß(1-6) linkages, were degraded to steviol mostly within 24 h. Given a common metabolite structure and a shared metabolic fate, safety data available for individual steviol glycosides can be used to support safety of purified steviol glycosides in general. Therefore, steviol glycosides specifications adopted by the regulatory authorities should include all steviol glycosides belonging to the five groups of steviol glycosides and a group acceptable daily intake established.

Antioxidant, anti-diabetic and renal protective properties of Stevia rebaudiana.

BACKGROUND: Stevia rebaudiana Bertoni has been used for the treatment of diabetes in, for example, Brazil, although a positive effect on antidiabetic and its complications has not been unequivocally demonstrated. This herb also has numerous therapeutic properties which have been proven safe and effective over hundreds of years. Streptozotocin is a potential source of oxidative stress that induces genotoxicity. OBJECTIVE: We studied the effects of stevia leaves and its extracted polyphenols and fiber on streptozotocin induced diabetic rats. We hypothesize that supplementation of polyphenols extract from stevia to the diet causes a reduction in diabetes and its complications. DESIGN/METHODS: Eighty Wistar rats were randomly divided into 8 groups; a standard control diet was supplemented with either stevia whole leaves powder (4.0%) or polyphenols or fiber extracted from stevia separately and fed for one month. Streptozotocin (60 mg/kg body weight, i.p) was injected to the diabetic groups on the 31st day. Several indices were analyzed to assess the modulation of the streptozotocin induced oxidative stress, toxicity and blood glucose levels by stevia. RESULTS: The results showed a reduction of blood glucose, ALT and AST, and increment of insulin level in the stevia whole leaves powder and extracted polyphenols fed rats compared to control diabetic group. Its feeding also reduced the MDA concentration in liver and improved its antioxidant status through antioxidant enzymes. Glucose tolerance and insulin sensitivity were improved by their feeding. Streptozotocin was also found to induce kidney damage as evidenced by decreased glomerular filtration rate; this change was however alleviated in the stevia leaves and extracted polyphenol fed groups. CONCLUSION: The results suggested that stevia leaves do have a significant role in alleviating liver and kidney damage in the STZ-diabetic rats besides its hypoglycemic effect. It might be adequate to conclude that stevia leaves could protect rats against streptozotocin induced diabetes, reduce the risk of oxidative stress and ameliorate liver and kidney damage.

An evidence-based systematic review of stevia by the Natural Standard Research Collaboration.

The objective of this study was to evaluate the scientific evidence on stevia, including expert opinion, folkloric precedent, history, pharmacology, kinetics/dynamics, interactions, adverse effects, toxicology, and dosing. This review serves as a clinical support tool. Electronic searches were conducted in 10 databases, 20 additional journals (not indexed in common databases), and bibliographies from 50 selected secondary references. No restrictions were placed on the language or quality of the publications. All literature collected pertained to efficacy in humans, dosing, precautions, adverse effects, use in pregnancy and lactation, interactions, alteration of laboratory assays, and mechanisms of action. Standardized inclusion and exclusion criteria were used for selection. Grades were assigned using an evidence-based grading rationale. Based on the availability of scientific data, two indications are discussed in this review: hypertension and hyperglycemia. Evaluation of two long-term studies (1 and 2 years in length, respectively) indicates that stevia may be effective in lowering blood pressure in hypertensive patients, although data from shorter studies (1-3 months) did not support these findings. A pair of small studies also report positive results with respect to glucose tolerance and response, although the relatively low methodological rigor of these experiments limits the strength of these findings. Further investigation is warranted in both indications.

Efectos agudos de la Stevia Rebaudiana en el manejo de la hiperglicemia inducida en ratones / Acute effects of Stevia Rebaudiana in the management of induced hyperglycemia in mice

La Stevia rebaudiana es una especie botanica nativa de Sudamérica. Es usado como sustituto del azucar por su sabor dulce, ademas posee efectos antihiperglucemiantes y antihipertensor Objetivo general: Determinar los efectos agudos de la Stevia rebaudiana en el manejo de la hiperglicemia inducida en ratones. Metodologia: Estudio Experimental de ensayo clinico. Se incluyeron en el estudio 30 ratones con peso promedio 33±0,67g. distribuidos en 5 grupos, los cuales fueron tratados con Stevia (dosis de 1g/K, 1,5g/K o 3g/k), insulina 0 placebo. Se midieron los valores de glicemla a distintos tiempos (60mln, 90min y 120min luego de una carga oral de glucosa). Resultados: Se considero p0,05. Las dosis de 1 y 3g/K no demostraron efecto antihiperglicemiante constante (p>0,05). La medicion a los 120 minutos todas las dosis de Stevia tuvieron en promedio, la glicemia menor al grupo placebo. La dosis de 1g/kg tuvo un efecto hiperglicemiante agudo a los 90 min (321 ,66mg/dL contra los 170,5mg/dLdel placebo), con p0,05). Las dosis de 1 y 3g/K no demostraron efecto antihiperglicemiante apreciable (p>0,05).La Stevia a dosis cle 1g/kg tiene un efecto hiperglicemiante agudo con una p<0,05

Investigation of the antihypertensive effect of oral crude stevioside in patients with mild essential hypertension.

The antihypertensive effect of crude stevioside obtained from the leaves of Stevia rebaudiana (Bertoni) Bertoni (Compositae) on previously untreated mild hypertensive patients was examined. Patients with essential hypertension were submitted to a placebo phase for 4 weeks. The volunteers selected in this phase were randomly assigned to receive either capsules containing placebo during 24 weeks or crude stevioside 3.75 mg/kg/day (7 weeks), 7.5 mg/kg/day (11 weeks) and 15.0 mg/kg/day (6 weeks). All capsules were prescribed twice a daily (b.i.d.), i.e. before lunch and before dinner. After the placebo phase and after each dose of crude stevioside, body mass index, electrocardiogram and laboratory tests were performed. During the investigation blood pressure (BP) was measured biweekly and the remaining data were collected at the end of each stevioside dose step. All adverse events were prospectively recorded but no major adverse clinical effects were observed during the trial. Systolic and diastolic BP decreased (p < 0.05) during the treatment with crude stevioside, but a similar effect was observed in the placebo group. Therefore, crude stevioside up to 15.0 mg/kg/day did not show an antihypertensive effect. Moreover, the results suggest that oral crude stevioside is safe and supports the well-established tolerability during long term use as a sweetener in Brazil.