Objective: The regular consumption of whole grains is linked to a lower likelihood of developing metabolic disorders. We previously found that chronic supplementation with wheat alkylresorcinols (ARs) prevents obesity and its associated metabolic symptoms induced by a high-fat high-sucrose diet (HFHSD) in mice. The aim of this study was to examine the time-of-day-dependence of these effects in mice.
Methods: Eight-wk-old male C57 BL/6 J mice were individually housed under a 12-h light/dark cycle (Zeitgeber time; ZT0, lights on; ZT12, lights off) and given access to a HFHSD from ZT12-16 (activity onset) and ZT20-24 (activity offset) to respectively represent breakfast and dinner times for 3 wk. Thereafter, the HFHSD was replaced with the same diet containing 0.4% ARs at either ZT12-16 or ZT20-24 for 8 wk. Control mice received the HFHSD without ARs at both feeding times.
Results: Supplementation with ARs significantly suppressed feed efficiency when given at breakfast, but not at dinner. ARs consumed at breakfast increased fecal lipid content and decreased the expression of Fat/Cd36 in enterocytes that enhances lipid uptake, but did not affect hepatic and blood lipid levels. The consumption of ARs at breakfast also upregulated the expression of Irs1, a key gene for insulin signaling in white adipose tissue and attenuated elevated blood leptin levels induced by the diet. This led to high scores for the homeostasis model assessment of insulin sensitivity, and the adiponectin/leptin ratio, a negative index of adipose tissue dysfunction.
Conclusions: These findings suggested that ARs ameliorate feed efficiency by decreasing dietary lipid absorption more effectively at the time of activity onset than offset. Further studies are needed to elucidate the molecular mechanism of the time-of-day-dependent effects of ARs on diet-induced metabolic disorders.
Keywords: Chrono-nutrition; Circadian rhythm; Lipid; Obesity; Polyphenol; Wheat alkylresorcinol.
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