Biometrological approaches for efficacy evaluation of beauty supplements and foods-part 2

contact gel is used to ensure uniform signal distribution.
The ultrasonic beam is emitted by a piezo-electric ceramic.
This beam is partially reflected by the interfaces separating
two different ultrasonic impedance media. At a frequency
of 7.5 MHz, the zone of exploitable echogenicity is in the
hypodermis.
This method allows a two dimensional visualization of subcutaneous
fat tissues. It is possible to quantify the effect
of a slimming product by measuring the decrease in the
hypodermis thickness (in mm) (Figure 1).
Three measurements of the hypodermis thickness are
taken (in millimetres): anterior side, posterior side and
lateral side of the thigh. The studied zones are accurately
relocalized at each kinetic times using a laser system.
Acquisition of 3D-pictures using PRIMOS® Body
PRIMOS® Body (Phaseshift Rapid In vivo Measurement
Of Skin) is a system for 3D cutaneous measurement based
on fringe projection that can be done directly in vivo. This
technology consists in calculating a phase image from the
projection of interference fringe images. This image is used
to calculate the altitude of each point.
This instrument was specifically adapted to avoid problems
due to shadows cast when large parts of the body are
being measured. To do this, two beams of light, instead of
one, are cast on the surface to be analyzed and the images
are recorded with two cameras forming a twenty-degree
angle (Figure 2)
The very short acquisition time prevents artefacts being
generated on the surface of the skin.
Calibrating and adjusting mechanisms aligned with
the measurement system ensure the precision of the
technique.
A 3D-picture of 20×30 cm_ is obtained and can be moved
in the 3 dimensions.
The analysis software allows then to reposition, in an
identical way the 3D pictures of each kinetic and to
compare them:
– a color code defines the increase or decrease of volume,
– on the studied zone, differences (in mm) are directly
calculated between profiles (vertical or horizontal)
and highlight the remodelling or slimming effect of the
treatment
Various areas can be studied: stomach, thighs (saddlebag
area), buttocks (Figure 3)
Desinfiltating claims/ Anti-fat nodes
Biometrological evaluation of desinfiltating or anti fat nodes
effects of a food supplement can be performed by:
– centimetric measurements and weight control,
– impedancemetry measurements (above-mentioned),
– measurement of the water retention with high frequency
echography (20 MHz)
– measurement of the dermis density and of the dermohypodermic
junction with high frequency echography (20
MHz)
High frequency echography (20 MHz)
Measurements were realised directly in vivo, using the high
frequency echograph Dermascan C® 2D equipped with a
20 MHz probe. The probe is applied directly to the skin. A
contact gel provides homogeneous diffusion of the signal.
The principle of the measurement is that of the echograph:
an ultrasound beam is emitted by a piezo-electric ceramic.
This beam is partially reflected by the interface separating
two media of different ultrasound impedance.
This method allows the bi-dimensional visualization (mode
B) of the skin, on the epidermis and dermis levels. During
the picture acquisition, the conjunctive tissue (= echogenic)
appears in colour (from yellow to green) whereas fat
inclusions or water (= non-echogenic) appears in black.
*Analysis of water retention
Water retention corresponds to a water filtration superior
to its reabsorption by venous and lymphatic capillaries.
This phenomenon can be quantified by measuring
thickness variations of the dermis thanks to high frequency
echography.
Dermis thickness is measured both at the ankle level and
at the internal part of the forearm.
Water retention Index (WRI) is calculated as
WRI = Dermis thickness at the internal part of the forearm
(mm)
Dermis thickness at the ankle’s level (mm)
In normal subject, WRI > 0.7. It means that skin thickness
of the ankle is superior to the forearm’s one but this
variation do not exceed 30%.
When WRI<0.7, the rise of dermis thickness at the ankle’s
level reflects water infiltration from venous capillaries.
* Analysis of dermis density and dermo-hypodermic
junction
In case of hypertrophied adipocytes, adipose panicles are
bigger. This is translated by a crenate junction between
dermis and hypodermis. A decrease in the linear length of
this dermo-hypodermic junction (in mm) characterizes an
anti-cellulite effect of a treatment (Figure 4). The skin image
obtained is also used to calculate dermis density, which is
inversely proportional to the quantity of fat infiltrated in the
skin.
Conclusion
Until very recently, the efficacy of cosmeceuticals with
slenderizing, desinfiltrating or anti-fat nodes claims was
evaluated by clinical scores, centimetric measurements
and weight control or self-assessment questionnaires.
These last years, news techniques have appeared allowing
to obtain accurate information about skin body contours,
structure or composition, directly in vivo and in a non
invasive way.
The bioelectrical impedancemetry is a method that allows
to estimate the body constituents and to determine the
slimming efficacy (fat mass / meagre mass, impedance)
and draining efficacy (hydric mass) of beauty supplements
and foods. It is an easy, quick and non-invasive technique,
recognised by the medical corps.
Among the different technique of skin imagery, ultrasound
is one of the most widespread. The differences in tissue
echogenic properties allow to get pictures of the skin.
Depending on the power of the probe, these pictures
provide a qualitative (visual) as well as a quantitative
evaluation of the morphology, the thickness of the different
cutaneous layers (dermis or hypodermis) and the nature
of the tissues themselves (density or aspect of the dermohypodermic
junction).
3D-optical measuring systems that allow in vivo surface
analysis, without contact have emerged recently. One of
these techniques uses fringe projection. It permits to obtain
3D representation of various body zones, such as the
thighs, the buttocks or the stomach…
The slenderizing action of cosmeceuticals or cosmetofoods
on these areas can be evaluated objectively, quickly and
without contact. This approach also offers nice pictures,
useful for the marketing services.
Of course, the techniques described above represent a non
exhaustive list. Nonetheless, they are representative of new
approaches that can objectively demonstrate the efficacy
of neutraceuticals, cosmeceuticals or cosmetofoods.
Thanks to such validated methodologies and reliable
clinical trials, the confidence of official institutions and
consumers in the claims performed can be gained.