Effect of Incorporating Genetic Testing Results into Nutrition Counseling and Care on Health Outcomes: An Evidence Analysis Center Systematic Review—Part II


      In recent years, literature examining implementation of nutritional genomics into clinical practice has increased, including publication of several randomized controlled trials (RCTs). This systematic review addressed the following question: In children and adults, what is the effect of incorporating results of genetic testing into nutrition counseling and care compared with an alternative intervention or control group, on nutrition-related health outcomes? A literature search of MEDLINE, Embase, PsycINFO, CINAHL, and other databases was conducted for peer-reviewed RCTs published from January 2008 until December 2018. An international workgroup consisting of registered dietitian nutritionists, systematic review methodologists, and evidence analysts screened and reviewed articles, summarized data, conducted meta-analyses, and graded conclusion statements. The second in a two-part series, this article specifically summarizes evidence from RCTs that examined health outcomes (ie, quality of life, disease incidence and prevention of disease progression, or mortality), intermediate health outcomes (ie, anthropometric measures, body composition, or relevant laboratory measures routinely collected in practice), and adverse events as reported by study authors. Analysis of 11 articles from nine RCTs resulted in 16 graded conclusion statements. Among participants with nonalcoholic fatty liver disease, a diet tailored to genotype resulted in a greater reduction of percent body fat compared with a customary diet for nonalcoholic fatty liver disease. However, meta-analyses for the outcomes of total cholesterol, low-density lipoprotein cholesterol, body mass index, and weight yielded null results. Heterogeneity between studies and low certainty of evidence precluded development of strong conclusions about the incorporation of genetic information into nutrition practice. Although there are still relatively few well-designed RCTs to inform integration of genetic information into the Nutrition Care Process, the field of nutritional genomics is evolving rapidly, and gaps in the literature identified by this systematic review can inform future studies.
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      A. Ellis is an associate professor, University of Alabama, Tuscaloosa.


      M. Rozga is a nutrition researcher, Academy of Nutrition and Dietetics Evidence Analysis Center, Chicago, IL.


      A. Braakhuis is academic director, Faculty of Medical and Health Science, Discipline of Nutrition, The University of Auckland, Grafton, Auckland, New Zealand.


      C. R. Monnard is a specialist in infant nutrition, Société des Produits Nestlé SA, Nestlé Research, Lausanne, Switzerland; at the time of the study, she was a postdoctoral fellow, University of Fribourg, Fribourg, Switzerland.


      K. Robinson is a medical science liaison, Scientific and Medical Affairs, Abbott Nutrition, Columbus, OH; at the time of the study, she was a postdoctoral researcher, Department of Internal Medicine, University of Iowa, Iowa City.


      R. Sinley is an assistant professor, Metropolitan State University of Denver, Denver, CO.


      A. Wanner is an information specialist consultant, Kelowna, British Columbia, Canada.


      A. J. Vargas is a scientist, Office of Disease Prevention, National Institutes of Health, Rockville, MD.

      Linked Article

      • Response to the Consensus Report of the Academy of Nutrition and Dietetics: Incorporating Genetic Testing into Nutrition Care
        Journal of the Academy of Nutrition and DieteticsVol. 120Issue 12
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          It is our pleasure to engage with the Academy of Nutrition and Dietetics in this important discussion on the impact of incorporating genetic testing into nutrition care. We reviewed, with interest, the Academy’s Consensus Report and companion papers detailing the conducted scoping and systematic reviews on the impact of genetic testing on dietary change and health outcomes.1-4 This work is of great importance, and we applaud the authors for encouraging registered dietitians to become involved in the research process1 in an effort to optimize pragmatic research in precision nutrition.
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