Krishnan Sridevi, Lee Fanny, Burnett Dustin J, Kan Annie, Bonnel Ellen L, Allen Lindsay H, Adams Sean H, Keim Nancy L
Western Human Nutrition Research Center, Agricultural Research Service, USDA, Davis, CA, USA.
Department of Nutrition, University of California, Davis, Davis, CA, USA.
Curr Dev Nutr. 2020 Feb 13;4(3):nzaa022. doi: 10.1093/cdn/nzaa022. eCollection 2020 Mar.
Controlled-feeding trials are challenging to design and administer in a free-living setting. There is a need to share methods and best practices for diet design, delivery, and standard adherence metrics.
This report describes menu planning, implementing, and monitoring of controlled diets for an 8-wk free-living trial comparing a diet pattern based on the Dietary Guidelines for Americans (DGA) and a more typical American diet (TAD) pattern based on NHANES 2009-2010. The objectives were to ) provide meals that were acceptable, portable, and simple to assemble at home; ) blind the intervention diets to the greatest extent possible; and ) use tools measuring adherence to determine the success of the planned and implemented menu.
Menus were blinded by placing similar dishes on the 2 intervention diets but changing recipes. Adherence was monitored using daily food checklists, a real-time dashboard of scores from daily checklists, weigh-backs of containers returned, and 24-h urinary nitrogen recoveries. Proximate analyses of diet composites were used to compare the macronutrient composition of the composite and planned menu.
Meeting nutrient intake recommendations while scaling menus for individual energy intake amounts and food portions was most challenging for vitamins D and E, the sodium-to-potassium ratio, dietary fiber, and fatty acid composition. Dietary adherence for provided foods was >95%, with no differences between groups. Urinary nitrogen recoveries were ∼80% relative to nitrogen intake and not different between groups. Composite proximate analysis matched the plan for dietary fat, protein, and carbohydrates. Dietary fiber was ∼2.5 g higher in the TAD composite compared with the planned menu, but ∼7.4 g lower than the DGA composite.
Both DGA and TAD diets were acceptable to most participants. This conclusion was supported by self-reported consumption, quantitative weigh-backs of provided food, and urinary nitrogen recovery. Dietary adherence measures in controlled-feeding trials would benefit from standard protocols to promote uniformity across studies. The trial is registered at clinicaltrials.gov as NCT02298725.
在自由生活环境中设计和实施对照喂养试验具有挑战性。需要分享饮食设计、供应和标准依从性指标的方法及最佳实践。
本报告描述了一项为期8周的自由生活试验中对照饮食的菜单规划、实施和监测情况，该试验比较了基于《美国膳食指南》（DGA）的饮食模式和基于2009 - 2010年美国国家健康与营养检查调查（NHANES）的更典型美国饮食（TAD）模式。目标是：1）提供可接受、便于携带且易于在家中组装的膳食；2）尽可能使干预饮食保持盲法；3）使用测量依从性的工具来确定计划和实施的菜单是否成功。
通过在两种干预饮食中放置相似的菜肴但改变食谱来使菜单保持盲法。使用每日食物清单、每日清单得分的实时仪表盘、返还容器的称重以及24小时尿氮回收率来监测依从性。对饮食组合进行近似分析以比较组合和计划菜单的宏量营养素组成。
在根据个体能量摄入量和食物份量调整菜单时，满足维生素D和E、钠钾比、膳食纤维和脂肪酸组成的营养摄入建议最具挑战性。提供食物的饮食依从性>95%，两组之间无差异。尿氮回收率相对于氮摄入量约为80%，两组之间无差异。组合近似分析与饮食脂肪、蛋白质和碳水化合物的计划相符。与计划菜单相比，TAD组合中的膳食纤维高约2.5克，但比DGA组合低约7.4克。
DGA和TAD饮食对大多数参与者来说都是可接受的。这一结论得到了自我报告的摄入量、提供食物的定量称重以及尿氮回收率的支持。对照喂养试验中的饮食依从性测量将受益于促进各研究之间一致性的标准方案。该试验已在clinicaltrials.gov上注册，注册号为NCT02298725。
