Effects of Short-term Fasting and Different Overfeeding Diets on Thyroid Hormones in Healthy Humans
Effects of Short-term Fasting and Different Overfeeding Diets on Thyroid Hormones in Healthy Humans
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DOI：
10.1089/thy.2019.0237
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发表时间：
2019-08-09
期刊：
影响因子：
6.6
通讯作者：
Piaggi, Paolo
中科院分区：
文献类型：
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作者：
Basolo, Alessio;Begaye, Brittany;Piaggi, Paolo
背景：禁食期间 24 小时能量消耗 (EE) 的较大下降和低蛋白过量喂养（代谢“节俭”表型）期间 24 小时能量消耗 (EE) 的较小增加可预测体重增加。由于甲状腺激素 (TH) 与能量摄入和代谢有关，我们评估了：(i) TH 浓度是否因 24 小时禁食或蛋白质含量不同的过量饮食而改变，以及 (ii) TH 的饮食相关变化与 EE 的伴随变化相关。方法：58 名血糖调节正常的甲状腺功能正常的健康受试者接受了 24 小时饮食干预，包括禁食、无热量喂养和五种过度喂养饮食，在全房间间接热量计中采用交叉设计来测量 24 小时 EE。过度喂养饮食（能量需求的 200%）包括三种含 20% 蛋白质的饮食、一种含 3% 蛋白质的饮食（低蛋白过度喂养饮食 [LPF]：46% 脂肪）和一种含 30% 蛋白质的饮食（高蛋白过度喂养饮食 [HPF]：44% 脂肪，n = 51）。每次饮食的早晨和之后禁食过夜后，测量血浆游离甲状腺素 (fT4)、游离三碘甲状腺原氨酸 (fT3) 和成纤维细胞生长因子 21 (FGF21) 浓度。结果：平均而言，禁食 24 小时后，fT4 增加 8%（+0.10 ng/dL，95% 置信区间 [CI 0.07-0.13]，p < 0.0001），fT3 减少 6%（-0.17 pg/mL [CI -0.27 至 -0.07]，p = 0.001），而 fT4 和 fT3 均下降HPF 后分别降低 5%（-0.07 ng/dL [CI -0.11 至 -0.04]，p < 0.0001）和 4%（-0.14 pg/mL [CI -0.24 至 -0.04]，p = 0.008）。 HPF 后 fT3 的较大下降与 FGF21 的较大下降相关（r = 0.40，p = 0.005）。 LPF 后，平均 fT3 增加 6% (+0.14 pg/mL [CI 0.05-0.2]，p = 0.003)，而 fT4 没有变化 (p = 0.7)。正常蛋白质过量喂养后，未观察到 TH 发生变化（所有 p > 0.1）。在任何饮食期间，未观察到 TH 浓度与饮食相关的 24 小时 EE 变化之间存在关联（所有 p > 0.07）。结论：仅在低蛋白质含量（0% 空腹和 3% 蛋白质过量喂养）或高蛋白质含量（30% 蛋白质过量喂养）饮食后，食物摄入量的急性（200%）短期（24 小时）变化才会引起 TH 浓度的微小变化。高蛋白过量喂养后的 fT3-FGF21 关联表明 TH 在蛋白质过量期间抑制肝脏分泌 FGF21 的作用。这些结果表明TH参与蛋白质代谢；然而，它们不会介导短期 EE 对饮食的反应，而饮食可以表征代谢表型并决定个体对体重增加的敏感性。
Background: A greater decrease in 24-hour energy expenditure (EE) during fasting and a smaller increase in 24-hour EE during low-protein overfeeding (metabolic "thrifty" phenotype) predict weight gain. As thyroid hormones (TH) are implicated in energy intake and metabolism, we assessed whether: (i) TH concentrations are altered by 24-hour fasting or overfeeding diets with varying protein content and (ii) diet-related changes in TH correlate with concomitant changes in EE. Methods: Fifty-eight euthyroid healthy subjects with normal glucose regulation underwent 24-hour dietary interventions including fasting, eucaloric feeding, and five overfeeding diets in a crossover design within a whole-room indirect calorimeter to measure the 24-hour EE. Overfeeding diets (200% of energy requirements) included three diets with 20% protein, one diet with 3% protein (low-protein overfeeding diet [LPF]: 46% fat), and one diet with 30% protein (high-protein overfeeding diet [HPF]: 44% fat, n = 51). Plasma free thyroxine (fT4), free triiodothyronine (fT3), and fibroblast growth factor 21 (FGF21) concentrations were measured after overnight fast the morning of and after each diet. Results: On average, fT4 increased by 8% (+0.10 ng/dL, 95% confidence interval [CI 0.07-0.13], p < 0.0001) and fT3 decreased by 6% (-0.17 pg/mL [CI -0.27 to -0.07], p = 0.001) after 24-hour fasting, whereas both fT4 and fT3 decreased by 5% (-0.07 ng/dL [CI -0.11 to -0.04], p < 0.0001) and 4% (-0.14 pg/mL [CI -0.24 to -0.04], p = 0.008) following HPF, respectively. Greater decreases in fT3 after HPF are associated with larger decreases in FGF21 (r = 0.40, p = 0.005). Following LPF, the mean fT3 increased by 6% (+0.14 pg/mL [CI 0.05-0.2], p = 0.003) with no change in fT4 (p = 0.7). No changes in TH were observed after normal-protein overfeeding diets (all p > 0.1). No associations were observed between TH concentrations and diet-related changes in 24-hour EE during any diet (all p > 0.07). Conclusions: Acute (200%) short-term (24 hours) changes in food intake induce small changes in TH concentrations only after diets with low (0% fasting and 3% protein overfeeding) or high (30% protein overfeeding) protein content. The fT3-FGF21 association after high-protein overfeeding suggests a role for TH in inhibiting FGF21 secretion by the liver during protein excess. These results indicate that TH are involved in protein metabolism; however, they do not mediate the short-term EE response to diets that characterize the metabolic phenotypes and determine the individual susceptibility to weight gain.