NEW YORK, May 26 (Reuters Health) - Drinking among some alcoholics may be a
way of increasing the body's levels of the brain chemical serotonin, according
to recent study findings, and low levels of this chemical may also cause them to
crave sweets.
Writing in the May issue of Alcoholism: Clinical and Experimental Research,
researchers led by Dr. Mona Moorhouse of the Royal Ottawa Hospital in Ontario,
Canada, explain that "carbohydrate craving may be an important clue to
developing more diversified treatments for alcohol-dependent subjects." The team
reports that diet has a significantly different effect on alcoholics who have
high cravings for carbohydrates compared with those who report lower levels of
cravings.
Alcohol and carbohydrates have both been shown to increase levels of
serotonin in the body, the researchers explain. Low levels of this chemical can
lead to depression, anxiety, aggression, and sleep problems.
The study involved 21 alcoholics who had been abstinent for 2 weeks and 12
non-alcoholics as a comparison group ('controls'). Participants completed
questionnaires about food and alcohol cravings, mood, depression and
personality. In addition to the questionnaires, the investigators measured blood
indicators of serotonin.
Ten of the alcoholic participants reported significant increases in their
cravings for carbohydrates when they abstained from drinking, and 11 reported
increases in cravings for foods rich in protein. These two groups were then
compared after eating special diets.
The alcoholic subjects, who were in a residential treatment facility, were
provided with 2 days of a high-carbohydrate, low-protein diet and with 2 days of
a high-protein, low-carbohydrate diet. The 'control' participants were
instructed to follow the same diets on their own.
After the high-carbohydrate diet, the alcoholics that reported carbohydrate
cravings showed significantly greater increases in symptoms of depression than
the other two groups, the researchers note. Depression scores after the
high-protein diet did not change for any of the groups.
The authors point out that sweets seem to have a paradoxical effect on
patients with high levels of craving: they appear to provide a brief improvement
in mood followed by a longer period of mood worsening. Similar findings have
been reported in patients with depression and bulimia.
In addition, carbohydrate-craving alcoholics reported significantly more
craving for alcohol during both types of diets than the other two groups, the
findings indicate. This group also showed more symptoms of personality disorder
than non-craving alcoholics.
Before the diet phase of the study, the alcoholic patients showed lower
levels of serotonin activity in the blood. The high-protein diet, however,
affected the two groups of alcoholics differently. This diet increased serotonin
activity in carbohydrate-craving patients, while it decreased serotonin activity
in non-craving patients and in controls.
Moorhouse and colleagues suggest that alcoholics with strong cravings for
carbohydrates may form a distinct subgroup of patients with this disease. This
type of alcoholic may drink to increase their serotonin levels, and may increase
their intake of carbohydrates if not drinking, to achieve the same effect, the
researchers suggest.
"Abnormal (serotonin) response to diet is specific to high
carbohydrate-craving subjects," the authors point out. "This response may
reinforce alcohol and/or food intake and perpetuate substance abuse," they add.
"High carbohydrate craving alcohol-dependent subjects are potentially at
greater risk for relapse than low carbohydrate craving alcohol-dependent
subjects," Moorhouse and colleagues continue, noting that the effects of diet
and alcohol on serotonin levels require further study.
