Division of Applied Life Sciences, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, Japan.
Clinical Research Institute, Division of Preventive Medicine, National Hospital Organization Kyoto Medical Center, Kyoto, Japan.
J Physiol Anthropol. 2024 Jan 4;43(1):5. doi: 10.1186/s40101-023-00353-0.
Human brown adipose tissue (BAT) activity is associated with lower body fatness and favorable glucose metabolism. Previous studies reported that oral fructose loading induces postprandial fibroblast growth factor 21 (FGF21) secretion. FGF21 is a known inducer of adipose tissue thermogenesis; however, the effects of diet-induced FGF21 secretion on BAT thermogenesis remain to be elucidated.
The effects of both single load and daily consumption of fructose on BAT activity were examined using a randomized cross-over trial and a 2-week randomized controlled trial (RCT), respectively. In the cross-over trial, 15 young men consumed a single dose of fructose solution or water and then consumed the other on a subsequent day. The RCT enrolled 22 young men, and the participants were allocated to a group that consumed fructose and a group that consumed water daily for 2 weeks. BAT activity was analyzed using thermography with cold exposure. Plasma FGF21 level was determined by enzyme-linked immunosorbent assay.
In the cross-over single-load trial, plasma FGF21 levels were significantly increased at 2 h after oral fructose load (p < 0.01); however, there was no significant difference in BAT activity between the fructose load and drinking water. The 2-week RCT revealed that both plasma FGF21 levels and BAT activity were not significantly increased by daily fructose consumption compared to water. Correlation analyses revealed that BAT activity at the baseline and the final measurements were strongly and positively associated with the RCT (r = 0.869, p < 0.001). Changes in BAT activity were significantly and negatively correlated with changes in plasma glucose levels during the 2-week intervention (r = - 0.497, p = 0.022).
Oral fructose load induces a temporary increase in circulating FGF21 levels; however, this does not activate BAT thermogenesis in healthy young men. Further studies are needed to elucidate the effect of endogenous FGF21 on physiological function.
This study is registered with the University Hospital Medical Information Network in Japan (number 000051761, registered 1 August 2023, retrospectively registered, https://center6.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000052680 ).
人体棕色脂肪组织（BAT）的活性与体脂率较低和葡萄糖代谢良好有关。先前的研究报告称，口服果糖负荷会诱导成纤维细胞生长因子 21（FGF21）的餐后分泌。FGF21 是已知的脂肪组织产热诱导剂；然而，饮食诱导的 FGF21 分泌对 BAT 产热的影响仍有待阐明。
本研究采用随机交叉试验和为期 2 周的随机对照试验（RCT），分别研究了单次负荷和每日摄入果糖对 BAT 活性的影响。在交叉试验中，15 名年轻男性饮用单剂量的果糖溶液或水，随后在第二天饮用另一种溶液。RCT 纳入了 22 名年轻男性，参与者被分配到每天摄入果糖或水的组，持续 2 周。使用冷暴露的热成像分析 BAT 活性。通过酶联免疫吸附试验测定血浆 FGF21 水平。
在交叉单次负荷试验中，口服果糖负荷后 2 小时血浆 FGF21 水平显著升高（p < 0.01）；然而，果糖负荷与饮水之间的 BAT 活性没有显著差异。2 周 RCT 显示，与饮水相比，每日摄入果糖并未显著增加血浆 FGF21 水平和 BAT 活性。相关性分析显示，RCT 时基线和最终测量的 BAT 活性与 RCT 呈强烈正相关（r = 0.869，p < 0.001）。2 周干预期间，BAT 活性的变化与血浆葡萄糖水平的变化呈显著负相关（r = - 0.497，p = 0.022）。
口服果糖负荷会引起循环 FGF21 水平的短暂升高；然而，这并没有激活健康年轻男性的 BAT 产热。需要进一步的研究来阐明内源性 FGF21 对生理功能的影响。
本研究在日本大学医院医疗信息网络（注册号 000051761，于 2023 年 8 月 1 日注册，回顾性注册，https://center6.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000052680）注册。
