JMIR Publications

ABSTRACT

Background:

Although gene-test based personalized nutrition is poised as the next paradigm of dietetics practice, its complexity presents barriers to implementation.

Objective:

To compare a self-driven approach to gene-test based nutrition education versus an integrated and individualized practitioner-facilitated method as a means to help develop improved interface tools for personalized nutrition practice.

Methods:

A sequential explanatory mixed methods investigation of 55 healthy adults (35-55 years) was conducted that included: 1) a 9-week RCT where participants were randomized to receive a standard nutrition-based gene test report (control; n=19) or a practitioner-facilitated personalized nutrition intervention integrating gene test results, health assessment data, and participant goals (intervention; n=36); and 2) interpretative thematic analysis of focus group interview data collected after the RCT to help interpret quantitative findings. Outcome measures of the RCT pre/post and group differences in diet quality (Healthy Eating Index-Canadian {HEI-C}; proportion {%} of calories from total fat, saturated fat, and sugar; omega 3 fatty acid intakes {grams}; sodium intakes {milligrams}) as well as Health-Related Quality of Life (HRQOL) scale scores. Two-way repeated measures ANOVA and binomial tests of two proportions compared pre/post differences of the outcomes.

Results:

Of the 55 (55/58 enrolled, 94.8%) participants who completed the study, most were between 40 to 51 years (67%), female (74.6%), in a relationship (85.5%), completed post-secondary education (61.8%), and earned a high household income (58.2%). Compared to baseline measures, significant group differences were found for percent of calories from total (mean difference {MD}=-5.1%, Wilks’ lambda ()=0.817, F(1,53)=11.68. p=0.001, eta-squared {2}=0.183 ) and saturated fat (MD=-1.7%, =0.816, F(1,53)=11.71, p=0.001, 2=0.18) as well as HRQOL scores (MD=+8.1 points, =0.914, F(1,53)=4.92, p=0.031, 2=0.086) compared to week-9 post-intervention measures. Significant interactions of time by group assignment were found for sodium intakes (=0.846, F(1,53)=9.47, p=0.003, 2=0.15) and HEI-C scores (=0.840, F(1,53)=9.921, p=0.003, 2=0.16). Analysis of phenotypic and genotypic information by group assignment found improved total fat (MD=-5%, =0.815, F(1,51)=11.36, p=0.001, 2=0.19) and saturated fat (MD=-1.3%, =0.822, F(1,51)=10.86, p=0.002, 2=0.18) intakes. Significant time by group interactions were found for sodium (=0.844, F(3,51)=3.09, p=0.035, 2=0.16); post-hoc analysis showed pre/post differences for those in the intervention group that did (pre-mean=3611mg, 95% CI 3039-4182; post-mean 2135mg, 95% CI 1564-2705) and did not have the gene risk variant (pre-mean=3722mg, 95% CI 2949-4496; post-mean 2071mg, 95% CI 1299-2843). Pre/post differences related to DRI guidelines showed increases in the proportion of intervention participants within the Acceptable Macronutrient Distribution Ranges for fat (pre/post difference=+41.2%, p=0.02). Qualitative analysis of textual data revealed three major themes: 1) Translation of nutrition-related gene test information to action which participants tried to do alone or by seeking out professionals to assist them; 2) Facilitation of eating behaviour change which tended to be easier for results for the macronutrients and sodium; and 3) Directives for future personalized nutrition practice which include providing easy to implement directives derived from gene-test based micronutrient information.

Conclusions:

While improvements were observed in both groups, healthy adults appear to derive better dietary outcomes and perceived health benefits from practitioner-led personalized nutrition interventions. In some instances, combining genotypic and phenotypic information facilitates positive dietary changes. Further work is needed in gene-based personalized nutrition education to better facilitate the comprehensive uptake of dietary advice, particularly for micronutrients. Clinical Trial: Clinicaltrials.gov NCT03310814, http://clinicaltrials.gov/ct2/show/ NCT03310814