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Test Científico Aquanergy

A continuación presentamos los resultados obtenidos en laboratorio que nos permiten certificar nuestras bebidas como de bajo índice glúcemico.



PRODUCT CODE: Me-10/1335

Professor Jeya Henry
Dr Sangeetha Thondre
Functional Food Centre
Oxford Brookes University

July 2010

The glycaemic index (GI), first introduced in 1981,1 is a classification of the blood glucose
raising potential of carbohydrate foods. It is defined as the incremental area under the blood
glucose curve of a 50 g carbohydrate portion of a test food expressed as a percentage of the
response to 50 g carbohydrate of a reference food taken by the same subject, on a different
day.2 In the case of foods with low to moderate carbohydrate density, it is justified to reduce
the carbohydrate load to 25 g to avoid an unrealistically large meal size. Such reductions are
shown to produce similar GI values.3
Carbohydrate foods consumed in isoglucidic amounts produce different glycaemic responses
depending on many factors, such as particle size, cooking and food processing, other food
components (e.g. fat, protein, dietary fibre) and starch structure.4 The principle is that the
slower the rate of carbohydrate absorption, the lower the rise of blood glucose level and the
lower the GI value.5 Indeed, high-GI foods are characterised by fast-release carbohydrate
and higher blood glucose levels. A GI value ³70 is considered high, a GI value 56-69
inclusive is medium and a GI value £55 is low (where glucose = 100).
The GI of foods may have important implications for the prevention and treatment of the
major causes of morbidity and mortality in Western countries, including Type 2 diabetes,
coronary heart disease and obesity. Today, there is an important body of evidence to
support the therapeutic potential of low-GI diets, not only in diabetes, 6-8 but also in subjects
with hyperlipidaemia.9 In addition, low GI foods have been associated with prolonged
endurance during physical activity, 10 improved insulin sensitivity11 and increased colonic
fermentation.12 More recent data support the preventive potential of a low-GI diet against the
development of Type 2 diabetes and cardiovascular disease.13-16
Study design and setting
A non-blind, randomised, repeat measure, crossover design trial was used to study the
glycaemic response to AQUANERGY (Product Code. ME-10/1335) against a reference of
glucose. Subjects acted as their own controls. The trial was conducted by the Functional
Food Centre at Oxford Brookes University. Ethical approval for the study was obtained from
the University Research Ethics Committee at Oxford Brookes University. Subjects were
given full details of the study protocol and the opportunity to ask questions. All subjects gave
written informed consent prior to participation.
Subject recruitment
Posters were distributed on notice boards throughout Oxford Brookes University to recruit
suitable subjects. In addition, recruitment of subjects was made through announcements in
lectures and through personal networks.
Ten healthy subjects (4 male, 6 female) were recruited for testing the AQUANERGY
(Product Code. ME-10/1335). Subjects were staff and students (undergraduate and
postgraduate) from Oxford Brookes University and were moderately active and non-smokers.
Prior to recruitment, all potential subjects completed a brief health questionnaire. Subjects
were excluded from the study if they met any of the following criteria:
• Aged 65 years
• Pregnant or lactating
• Body mass index (BMI) ³ 30kg/m2
• Fasting blood glucose value > 6.1 mmol/l
• Medical condition(s) or medication(s) known to affect glucose regulation or appetite
In addition, subjects were excluded if they were unable to comply with experimental
procedures or did not follow GI testing safety guidelines.
Anthropometric measurements
For all subjects, anthropometric measurements were made in the fasting state during the first
session. Height was recorded to the nearest centimetre using a stadiometer (Seca Ltd, UK),
with subjects standing erect and without shoes. Body weight was recorded to the nearest
0.1 kg, with subjects wearing light clothing and no shoes. Body mass index (BMI) was
calculated using the standard formula: weight (kg)/height (m)2. Body fat percentage was
measured using a body composition analyser (Tanita BC-418 MA; Tanita UK Ltd). The
physical characteristics of the study population are presented in Table 1.

Table 1 Physical characteristics of study population (mean ± SD) for AQUANERGY
(Product Code. ME-10/1335)
All subjects (n 10)
Age (y)        33 ± 9
Height (m) 1.7 ± 0.1
Weight (kg) 60.4 ± 9.5
BMI (kg/m2) 21.7 ± 1.9
Fat mass (%) 18.7 ± 7.9
Lean body mass (kg) 49.1 ± 9.0

The protocol used by the Functional Food Centre at Oxford Brookes University is adapted
from that described by Brouns et al.3 and is in line with procedures recommended by the
FAO/WHO.2 The FAO/WHO state that to determine the GI of a food, tests should be
repeated in six or more subjects. Thus, in the current study, ten subjects were tested.
The day prior to a test
On the day prior to a test, subjects were asked to restrict their intake of alcohol and caffeinecontaining
drinks and to restrict their participation in intense physical activity (e.g. long
periods at the gym, excessive swimming, running, aerobics). Subjects were also told not to
eat or drink after 9 pm the night before a test, although water was allowed, in moderation.
Test drink
AQUANERGY (Product Code. ME-10/1335) was compared with a reference food (glucosemonohydrate)
and was tested in equivalent carbohydrate amounts (50 g). The amount of
AQUANERGY (Product Code. ME-10/1335) to be served was provided by SOLUCIONES
Table 2 Amount served to provide 50 g available carbohydrate
Glucose-monohydrate                                        55 g
AQUANERGY (Product Code. ME-10/1335)    360 ml

As blood glucose responses vary considerably day to day within subjects, FAO/WHO
recommend that the reference food be repeated at least three times in each subject to obtain
a representative mean response to the reference food.2 Thus, all subjects tested

AQUANERGY (Product Code. ME-10/1335) once and the reference food three times in
random order on separate days, with at least a one-day gap between measurements to
minimise carry over effects. Subjects were studied in the morning after a 12-hour overnight
fast. Subjects consumed the reference food/ AQUANERGY at a comfortable pace, within
15 minutes. The reference food was served with 250 ml water. Subjects remained
sedentary during each session.
Blood glucose measurements
Blood samples were taken at -5 min and 0 min before consumption of the reference food/
AQUANERGY and the baseline value taken as a mean of these two values. The reference
food/ AQUANERGY was consumed immediately after this and further blood samples were
taken at 15, 30, 45, 60, 90 and 120 minutes after starting to eat. A post-prandial 2-hour
period for blood glucose measurements has been demonstrated to be sufficient for the
determination of GI values in healthy subjects.
Blood was obtained by finger-prick using the Unistik®3 single-use lancing device (Owen
Mumford). Recent reports suggest that capillary blood sampling is preferred for reliable GI
testing.2, 17 Prior to a finger-prick, subjects were encouraged to warm their hand to increase
blood flow. Fingers were not squeezed to extract blood from the fingertip as this may dilute
with plasma. Blood glucose was measured using the HemoCue Glucose 201+ analyser
(HemoCue® Ltd), which was calibrated daily using control solutions from the manufacturer
and also regularly calibrated against the YSI 2300 STAT Plus™ glucose and lactate analyzer
(YSI UK Ltd).
Calculation of GI
A number of different methods have been used to calculate area under the curve (AUC). In
the present study, the incremental area under the blood glucose response curve (IAUC) was
calculated geometrically by applying the trapezoid rule, ignoring the area beneath the
baseline.2 The IAUC for the AQUANERGY for each subject was expressed as a percentage
of the mean IAUC for the reference food eaten by the same subject:
GI = (IAUC AQUANERGY / IAUC reference food) * 100
The GI value of the AQUANERGY was taken as the mean for the whole group.
Table 3 and Fig.1 illustrate the mean blood glucose levels and mean change in blood
glucose for the AQUENERGY.
Table 3 Mean blood glucose measurements (mmol/l)
Time (min)              AQUANERGY (Product Code. ME-10/1335)
0                                    4.8
15                                  6.4
30                                  6.7
45                                  5.8
60                                  4.8
90                                  4.4
120                                4.3

Fig.1. Glycaemic response curves for glucose and AQUENERGY (Product Code. ME-
The GI value of AQUANERGY (Product Code. ME-10/1335) was calculated for each
subject from the IAUC for the product compared to that for the reference. The GI of
AQUANERGY (Product Code. ME-10/1335) was taken as the mean for the whole group.
The GI value and GI classification are summarised in Table 4.
Table 4 GI value [glucose = 100] and classification
GI value (mean ± SEM)       Classification
AQUANERGY   44 ± 5                  Low

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