The effect of L-arabinose on the glycaemic and insulinemic response after consumption of a liquid product.

L-arabinose is a pentose which is naturally present in plants, e.g. in the
sugar beet. L-arabinose is a sucrase inhibitor and lowers glucose and insulin
responses when it is consumed together with sucrose. However, when L-arabinose
is consumed in a muffin, in cereal clusters or in a mixed meal, no significant
lowering of the glycaemic response was observed. Fat, starch and protein are
nutrients present in solid products and less in drinks. We hypothesize that the
macronutrient content of the meal disturbs the positive effect of L-arabinose.
We expect that fat will reduce the glycaemic response by delaying gastric
emptying, which causes a slower entrance in the duodenum of sucrose and
L-arabinose. For starch we expect that the glycaemic response will be so much
increased that the inhibiting effect on sucrase may be diminished, by an
increased presence of glucose in the duodenum. For now, we want to know how
much the separate effects of fat and starch will be.

The objective of the study is to determine and compare the effects of
L-arabinose added to 1) water with sucrose, 2) water with sucrose and fat, and
3) water with sucrose and starch on glycaemic and insulinemic responses in
healthy adults.

The secondary aims are to determine and compare the effects of L-arabinose
added to 1) water with sucrose, 2) water with sucrose and fat, and 3) water
with sucrose and starch on:
1) appetite ratings,
2) subsequent ad libitum energy intake,
3) tolerance of the treatments,
4) gastro-entero endocrine markers,
5) L-arabinose in the blood, and
6) excretion of L-arabinose in urine.

The study is a randomized cross-over trial with six treatments divided in three
blocks and blind within the blocks. All participants will receive 6 treatments
in a randomized order. There will be a washout period between treatments of a
minimum of three days. The test products will be consumed after an overnight
fast.

All products contain 50g sucrose and 250g water. The testproducts are:
1) Control sucrose solution (50g sucrose)
2) L-arabinose sucrose solution (Control + 5g L-arabinose)
3) Sucrose and fat solution (Control + 22g fat)
4) Fat L-arabinose and sucrose solution (Control + 5g L-arabinose + 22g fat)
5) Sucrose and starch solution (Control + 50g starch)
6) Starch L-arabinose and sucrose solution (Control + 5g L-arabinose + 50g
starch)

The intervention is non-therapeutic to the subjects. The risk associated with
participation is negligible and the burden can be considered as moderate.
L-arabinose is a pentose which is present in a wide range of plants, such as
sugar beet. The safety of L-arabinose is evaluated by legal authorities and it
has been classified as self-affirmed GRAS in the USA.
After signing the informed consent the following measurements and
questionnaires are taken: General questionnaire, health questionnaire and Dutch
Eating Behaviour Questionnaire. At screening the following measurements will be
taken: height, body weight, fasting blood via finger prick to determine
glucose, and Hb concentration. On the evenings before the experimental test
days, subjects will consume every time the same evening meal. During the test
morning subjects need to come in a fasting state to the University. Then, 8
blood samples (80 ml per test morning) and appetite questionnaires will be
collected in 180 minutes, subsequent ad libitum lunch intake, as well as a
gastro-intestinal comfort questionnaire, and an evaluation questionnaire to ask
which treatment they thought they had. Additionally, subjects will collect
urine for 24h during and after the test day. The total study lasts for six
weeks. So, including the information meeting, screening and returning their
urine containers the subjects need to visit the University 14 times.