Dietary curcumin supplement promotes browning and energy expenditure in postnatal overfed rats

Abstract Background: Early postnatal overfeeding could result in metabolic imprinting that decreases energy expenditure following with white adipose tissue (WAT) gain throughout life. This research was to investigate whether curcumin (CUR) supplement could promote WAT browning and activate thermogenesis in postnatal overfed rats.Methods and results: This study adjusted the size of litters to three (small litters, SL) or ten (normal litters, NL) to mimic early postnatal overfeeding or normal feeding from postnatal day 3. From postnatal week 3 (weaning period), the SL rats were fed with a standard diet (SL) or a diet supplemented with 1% (SL1% CUR) or 2% (SL2% CUR) CUR for ten weeks. At postnatal week 13, SL rats with 1% or 2% CUR supplement had lower body weight and less WAT gain, had increased lean mass ratio, and their glucose tolerance and blood lipid levels had recovered to normal when compared to SL rats that did not receive the supplement. Moreover, increased respiratory exchange ratio (RER) and heat generation were consistent with expression levels of uncoupling protein 1 (UCP1) and other browning-related genes in the subcutaneous adipose tissue (SAT) of the SL2% CUR rats but not of the SL1% CUR rats. In addition, 2% CUR dietary supplement enhanced the serum norepinephrine (NE) levels in SL rats, with the upregulated mRNA levels of β3-adrenergic receptor (β3-AR) in SAT.Conclusion: Dietary CUR supplement attenuates body weight gain and metabolic disorders in SL, which might be induced by promoting browning of SAT and energy expenditure. Moreover, the benefits were more obvious in SL with 2% CUR supplement.