Designing, Conducting, and Documenting Human Nutrition Plant-Derived Intervention Trials

Abstract

Best practices for designing, conducting, documenting, and reporting human nutrition randomized controlled trials were developed and published in Advances in Nutrition. Through an example of the randomized clinical trial on blueberries and bone health funded by the National Institutes of Health, this paper will illustrate the elements of those best practices that apply specifically to plant-based intervention clinical trials. Unique study design considerations for human feeding interventions with bioactive plant compounds include the difficulty of blinding the intervention, background nutritional status of participants, carry-over effects of the intervention, benefits of a run-in period, lack of safety/tolerability data, and nutrition-specific regulatory policies. Human nutrition randomized controlled trials are the gold standard for establishing causal relations between an intervention and health outcome measures. Rigorous studies and documentation define the quality of the evidence-base to inform public health guidelines and to establish personalized dietary recommendations for the health-promoting plant components.

Moderate consumption of freeze-dried blueberry powder increased net bone calcium retention compared with no treatment in healthy postmenopausal women: a randomized crossover trial

“…The product composition, energy, macronutrient, and polyphenol contents are shown in Table 1 . The methods of ensuring the stability of polyphenols and product palatability were described previously [ 20 ].…”

Perspectives on the application of CONSORT guidelines to randomised controlled trials in nutrition

“…An example of documenting a whole blueberry freeze-dried powder intervention is described by Weaver and Hodges [51]. This paper discusses many elements for reporting nutrition trials using food bioactives, including description of the intervention, monitoring stability of the polyphenol bioactives, monitoring compliance through serum polyphenol metabolite biomarkers, and safety considerations.…”

“…The participant may not be able to see a difference in salt level if that is the only variable, but they can taste the difference between high and low salt levels. Weaver and Hodges [51] describe the problems with blinding of intensely coloured products. Even when the intervention or comparator cannot be blinded from the participants or those who deliver the intervention, the staff who perform testing and the analyses can be blinded, and this should be described.…”

Quantifying the effect of nutritional interventions on metabolic resilience using personalized computational models

“…Currently, much of the evidence that underlies lifestyle intervention recommendations are obtained from large epidemiological or clinical studies. In nutritional research, the gold-standard for assessing intervention success is the randomized, double-blinded, placebo-controlled trial, 11 , 12 whereby the effectiveness of a given diet intervention is determined by comparing the change in an outcome measure such as body weight or fasting glucose in the intervention group to a control group. 13 By reducing the population level response to averages, or generic cut-offs, these studies often neglect the sometimes-considerable inter-individual variation that may exist in intervention effect.…”