No Effect of Dietary Fish Oil Supplementation on the Recruitment of Brown and Brite Adipocytes in Mice or Humans under Thermoneutral Conditions

Mol Nutr Food Res. 2021 Jan;65(2):e2000681. doi: 10.1002/mnfr.202000681. Epub 2020 Dec 21.


Scope: Brown and brite adipocytes within the mammalian adipose organ provide non-shivering thermogenesis and thus, have an exceptional capacity to dissipate chemical energy as heat. Polyunsaturated fatty acids (PUFA) of the n3-series, abundant in fish oil, have been repeatedly demonstrated to enhance the recruitment of thermogenic capacity in these cells, consequently affecting body adiposity and glucose tolerance. These effects are scrutinized in mice housed in a thermoneutral environment and in a human dietary intervention trial.

Methods and results: Mice are housed in a thermoneutral environment eliminating the superimposing effect of mild cold-exposure on thermogenic adipocyte recruitment. Dietary fish oil supplementation in two different inbred mouse strains neither affects body mass trajectory nor enhances the recruitment of brown and brite adipocytes, both in the presence and absence of a β3-adrenoreceptor agonist imitating the effect of cold-exposure on adipocytes. In line with these findings, dietary fish oil supplementation of persons with overweight or obesity fails to recruit thermogenic adipocytes in subcutaneous adipose tissue.

Conclusion: Thus, the authors' data question the hypothesized potential of n3-PUFA as modulators of adipocyte-based thermogenesis and energy balance regulation.

Keywords: adipose tissue; fish oil; n3; n6; obesity; polyunsaturated fatty acids; thermogenesis; uncoupling protein 1.

Publication types

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

MeSH terms

  • Adipocytes, Beige / drug effects*
  • Adipocytes, Brown / drug effects*
  • Adipose Tissue, White / cytology
  • Adipose Tissue, White / drug effects
  • Adult
  • Animals
  • Dietary Supplements
  • Fatty Acids, Omega-3 / metabolism
  • Fatty Acids, Omega-3 / pharmacology*
  • Female
  • Fish Oils / pharmacology*
  • Gene Expression Regulation / drug effects
  • Glucose Tolerance Test
  • Humans
  • Male
  • Mice, Inbred C57BL
  • Mice, Inbred Strains
  • Middle Aged
  • Palm Oil / pharmacology
  • Plant Oils / pharmacology
  • Subcutaneous Fat / drug effects*
  • Subcutaneous Fat / physiology
  • Thermogenesis / drug effects
  • Thermogenesis / physiology
  • gamma-Linolenic Acid / pharmacology


  • Fatty Acids, Omega-3
  • Fish Oils
  • Plant Oils
  • Palm Oil
  • gamma-Linolenic Acid
  • borage oil