The effect of moderate alcohol consumption on subsequent food reward

It has been shown in several studies that alcohol increases subsequent food
intake. A chronic increased food intake can lead to obesity. In the Western
world, where palatable food is highly available, hedonic motives probably play
an important role in food intake behaviour besides the effects of hunger and
satiety hormones. Consumption occurs often as a result of hedonic motives,
because palatable food is very rewarding. Alcohol consumption is known to
stimulate neurotransmitters important for reward, such as dopamine, opioids and
endocannabinoids. Therefore, the effect of moderate alcohol consumption on
reward could stimulate also the reward response on a subsequent meal, resulting
in a higher consumption than when no alcohol is consumed.
It is hypothesized that the reward response of food or beverages can already be
generated when food or beverages are sensed in the mouth, because oral nutrient
sensing is known to induce a satiety response (i.e. the cephalic phase
response). Moreover, taste bud nerves directly signal to brain areas closely
connected to the reward areas in the brain.

Primary Objective
To determine whether moderate alcohol consumption influences subsequent food
reward, as measured by questionnaires on food *wanting* and food *liking*, and
salivary and blood parameters related to food reward.

Secondary Objectives
To determine whether food reward is different when food is consumed than when
food is sensed in the mouth, as measured by questionnaires on food *wanting*
and food *liking*, and salivary and blood parameters related to food reward.

To determine whether moderate alcohol consumption influences subsequent food
reward differently when food is consumed than when food is sensed in the mouth,
as measured by questionnaires on food *wanting* and food *liking*, and salivary
and blood parameters related to food reward.

Randomized, placebo-controlled, single-blind, cross-over trial

This research consists of 6 treatment days. Each treatment day one of the
following combinations of food will be researched:
1. 200 mL vodka orange juice mix + 40 g cake for consumption
2. 200 mL vodka orange juice mix + 40 g cake for modified sham feeding (chew
and expectorate)
3. 200 mL vodka orange juice mix
4. 175 mL orange juice (including 31 g maltodextrin) + 40 g cake for consumption
5. 175 mL orange juice (including 31 g maltodextrin) + 40 g cake for modified
sham feeding (chew and expectorate)
6. 175 mL orange juice (including 31 g maltodextrin)

Expected adverse events during the study
An amount of 65 ml of vodka will probably not cause adverse effects.
Consumption of 20 gram alcohol (equal to 2 standard glasses in The Netherlands)
is common and widespread under the population without causing adverse effects.
However, people may feel nauseous or tired because of the alcohol. In addition,
the placement of an intravenous cannula could cause pain, hematomas and, in
rare cases, phlebitis. Filling out the questionnaires can lead to tiredness.

Expected benefit:
The participants will not have a direct benefit of participation.

Ongemakken:
Repeated blood collection; 24 times during the study (total circa 492 mL)