Malabsorption of carbohydrates and depression in children and adolescents

J Pediatr Gastroenterol Nutr. 2005 May;40(5):561-5. doi: 10.1097/01.mpg.0000153005.61234.28.


Background: Previous studies have shown an association between sugar malabsorption and depressive symptoms in adult women. Incompletely absorbed sugars may form nonabsorbable complexes with tryptophan, an amino acid precursor of serotonin, decreasing its availability. As serotonin is the most important neurotransmitter involved in depressive disorders, its depletion could lead to the onset of depression.

Methods: The authors' aim was to study the possible association between malabsorption of sugars (lactose and fructose) and depressive symptoms in adolescent patients of Spanish origin. The authors studied two groups of patients. Group G included 14 patients previously diagnosed with sugar intolerance. In these, the authors assessed depressive symptoms. Group P consisted of seven patients suffering from major depression. In these, the authors performed functional sugar absorption tests. The authors studied the metabolic pathway of tryptophan in both groups.

Results: In the group with sugar malabsorption, there was a 28.5% prevalence of depressive symptoms that was higher than expected in our population. In the group with depression, the authors found a higher than expected prevalence of sugar intolerance (71.42% versus 15% in controls).

Conclusions: The unexpected prevalences obtained for the groups studied suggest that there may be an association between sugar intolerance and depressive symptoms during adolescence.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Biological Availability
  • Child
  • Depression / epidemiology
  • Depression / etiology*
  • Depression / metabolism
  • Dietary Carbohydrates / metabolism
  • Dietary Carbohydrates / pharmacokinetics*
  • Female
  • Fructose / metabolism
  • Fructose / pharmacokinetics*
  • Humans
  • Intestinal Absorption
  • Lactose / metabolism
  • Lactose / pharmacokinetics*
  • Lactose Intolerance / complications
  • Lactose Intolerance / epidemiology
  • Malabsorption Syndromes / complications*
  • Malabsorption Syndromes / epidemiology
  • Male
  • Serotonin / metabolism
  • Spain / epidemiology
  • Tryptophan / metabolism


  • Dietary Carbohydrates
  • Fructose
  • Serotonin
  • Tryptophan
  • Lactose