An RCT Examining the Effect of Precision Nutrition on Health-Related Behavior Change of AD Service Members

Background: Growing public awareness and a plethora of scientific evidence regarding the consequences of vitamin D insufficiency speak to the relevance of the team’s previous study examining vitamin D–related gene expression in response to supplementation. Preliminary results are noteworthy and inform this extension of the role of nutrigenomics, or nutrient impact on gene activity, in disease prevention. Self-reported symptoms (fatigue and sleep) and 25(OH)D levels demonstrate unique responses to low vs high dose vitamin D supplementation. In addition, in-person interviews documented that vitamin D intake met only 43% of the Recommended Dietary Allowance of 600 IU daily. Over 2000 genes are involved in vitamin D metabolism alone; diet and environmental exposures (sunlight, physical activity) likely influence alterations in the vast network of genes contributing to common chronic diseases, such as cardiovascular disease, stroke, cancer, and type II diabetes.

Purpose: Using published literature and omics databases to develop the necessary risk profile of genes and single nucleotide polymorphisms (SNPS), conduct a focused and personalized nutrition counseling intervention for service members to promote healthy living and disease prevention through diet and physical activity.

Specific aims: 1) Examine the effectiveness of precision nutrition counseling on health-related behavior change in a military population; 2) Evaluate the feasibility of a digital application to accurately capture dietary intake, environmental exposure, and physical activity; and 3) Describe military-unique characteristics in demographics, lifestyle choices, and geographic exposures for a northwest Army cohort and a southwest Air Force cohort. Methods: Team nurse scientists will identify candidates for participation from Service populations who will be available for the duration of the protocol; 6-week intervention followed by outcome measures at 12 weeks. We will use a multi-modal approach to acquire real-time health data, creating a digital phenotype validated by in-person interviews, for 150 Army and Air Force SMs following baseline determination of genetic risk for alterations in endocrine, cardiovascular, and bone health. Participants will be randomized and stratified by gender and race to a genotype-based counseling intervention or standard dietary recommendations available from military nutrition clinics. Genetic information will be derived from loci associated with BMI/adiposity, CVD, and low vitamin D. Lipid and iron profiles, nutrient stores (vitamin D, folate, calcium), and endocrine function (SHBG, TSH) will comprise the serum biomarkers. Body composition, blood pressure, and physical activity levels, along with dietary intake constitute phenotype or the set of observable characteristics that are distinct and measurable arising from gene-environment interactions. The cohorts being studied were purposely chosen to provide insight into the diversity in exposures by demographics (age, gender, race, ethnicity, etc.) and geographic location. Primary outcomes include variables that reflect the nutrigenomic-based risk for metabolic syndrome i.e. fasting glucose, LDL/HDL, %body fat, waist circumference, blood pressure, and 25(OH)D levels. Secondary outcomes include nutrient adequacy, environmental exposures (sun, physical activity). Analysis: Interpretation of genomic data and creation of genetic risk scores will be done with a bioinformatician. All data analysis will be performed using R software with careful description of relevant subgroups. Strength of relationships among variables will be interpreted using effect sizes and standardized mean differences. Alpha coefficients of reliability will be calculated for instruments.

Relevance: This original and highly complex undertaking begins to set the stage for advancing the precision nutrition agenda in the military setting where advanced practice nurses and registered dietitians can use genotype-based risk data to guide diet and lifestyle counseling of SMs that will support current and future personal and military unit readiness and optimize mission performance.