An examination of the effects of isoenergetic intragastric infusions of pure macronutrients on cold pain perception in healthy human volunteers

Physiol Behav. 1999 Jan 1-15;65(4-5):643-8. doi: 10.1016/s0031-9384(98)00231-5.


Our previous study demonstrated that meals, particularly when rich in fat, significantly reduced the pain induced by the cold pressor stimulus in healthy human subjects. To determine the mechanisms involved, the aim of this study was to bypass the taste and cognitive component of food and to investigate the scope of these analgesic effects with direct intragastric infusion of pure macronutrients in a group of 16 healthy human volunteers (eight male and eight female) on the response to cold-induced pain. All subjects underwent the cold pressor test (CPT) on three occasions in a counterbalanced order: before and after intragastric intubation and infusion of isoenergetic fat (10% intralipid), carbohydrate (CHO-maltodextrin), and a control infusion of isotonic saline. All solutions were of equal volume and administered at room temperature. The CPT was carried out four times on each test day, once before intubation, and 0.5, 1.5, and 2.5 h after intragastric infusion. Radial pulse and blood pressure measurements and visual analogue scales of mood/emotional state were carried out before and after each CPT. There were no significant differences in pain scores between the three test conditions, suggesting that by bypassing the cognitive and taste component of eating, the trigger for any postingestive analgesic effects of food are lost.

Publication types

  • Clinical Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Affect / physiology
  • Blood Pressure / physiology
  • Cold Temperature / adverse effects*
  • Dietary Carbohydrates / administration & dosage
  • Dietary Carbohydrates / pharmacology*
  • Dietary Fats / administration & dosage
  • Dietary Fats / pharmacology*
  • Energy Metabolism / physiology*
  • Female
  • Heart Rate / physiology
  • Humans
  • Immersion
  • Intubation, Gastrointestinal
  • Male
  • Pain / psychology*
  • Pain Measurement
  • Sex Characteristics
  • Time Factors


  • Dietary Carbohydrates
  • Dietary Fats