Department of Clinical Nutrition, German Institute of Human Nutrition Potsdam-Rehbruecke, 14558 Nuthetal, Germany.
German Center for Diabetes Research (DZD), 85764 München-Neuherberg, Germany.
Nutrients. 2020 Jan 28;12(2):340. doi: 10.3390/nu12020340.
Meal timing affects metabolic regulation in humans. Most studies use blood samples for their investigations. Saliva, although easily available and non-invasive, seems to be rarely used for chrononutritional studies. In this pilot study, we tested if saliva samples could be used to study the effect of timing of carbohydrate and fat intake on metabolic rhythms. In this cross-over trial, 29 nonobese men were randomized to two isocaloric 4-week diets: (1) carbohydrate-rich meals until 13:30 and high-fat meals between 16:30 and 22:00 or (2) the inverse order of meals. Stimulated saliva samples were collected every 4 h for 24 h at the end of each intervention, and levels of hormones and inflammatory biomarkers were assessed in saliva and blood. Cortisol, melatonin, resistin, adiponectin, interleukin-6 and MCP-1 demonstrated distinct diurnal variations, mirroring daytime reports in blood and showing significant correlations with blood levels. The rhythm patterns were similar for both diets, indicating that timing of carbohydrate and fat intake has a minimal effect on metabolic and inflammatory biomarkers in saliva. Our study revealed that saliva is a promising tool for the non-invasive assessment of metabolic rhythms in chrononutritional studies, but standardisation of sample collection is needed in out-of-lab studies.
进食时间影响人体的代谢调节。大多数研究使用血液样本进行调查。唾液虽然容易获得且无创，但似乎很少用于时间营养研究。在这项初步研究中，我们测试了唾液样本是否可用于研究碳水化合物和脂肪摄入时间对代谢节律的影响。在这项交叉试验中，将 29 名非肥胖男性随机分配到两种等热量的 4 周饮食中：（1）富含碳水化合物的餐点在 13:30 之前，高脂肪餐点在 16:30 至 22:00 之间；或（2）相反的用餐顺序。在每个干预结束时，每 4 小时收集一次 24 小时的刺激唾液样本，并评估唾液和血液中的激素和炎症生物标志物水平。皮质醇、褪黑素、抵抗素、脂联素、白细胞介素-6 和 MCP-1 表现出明显的昼夜变化，反映了血液中的日间报告，并与血液水平呈显著相关性。两种饮食的节律模式相似，表明碳水化合物和脂肪摄入的时间对唾液中的代谢和炎症生物标志物影响很小。我们的研究表明，唾液是时间营养研究中评估代谢节律的一种很有前途的无创工具，但在实验室外研究中需要对样本采集进行标准化。
