Metabolomics-Driven Insights Into Ultra-Processed Foods

UPFs, characterized by industrial processing and the use of cosmetic additives for enhanced palatability and extended shelf-life, account for approximately 58% of caloric intake in the U.S. population. Although some UPF subtypes have been implicated in increasing risk of T2D and other chronic diseases, others may be relatively inert or even beneficial, underscoring the need for discerning their distinct health effects. This trial is a controlled crossover feeding trial design with target enrollment of 40 generally healthy adults. Partcipants complete 3 2-week isocaloric dietary intervention phases, with 1 week of a control diet of non-ultraprocessed foods and beverages, and 1 week of a UPF-based test diet. The 3 UPF test diets each feature a menu consisting of a UPF subtype: starchy and refined grains, meats and fish, or dairy-based products. Foods and beverages are provided during the diet phases, and participants will attend weekly clinic visits for in-person assessments and biospecimen collections. We will obtain metabolomic profiling of the fasting plasma samples and conduct data analyses to isolate novel biomarkers that reflect the intake of the UPFs, such as industrial additives. These objective signatures of UPF intake will support subsequent research investigating the long-term health outcomes relate d to UPF consumption. Identifying metabolomic signatures of UPF subtypes will enhance the understanding of the biological mechanisms linking UPFs to T2D and other chronic disease risks.

• UPF Test Diet A: Starchy, refined grains (Other): The 2-week diet phase includes a standardized control run-in diet with non-UPFs only for 7 days, immediately followed by a 7-day UPF test diet with \~60% of calories from UPFs consistently of starchy foods and refined grain products. Participants receive all study-provided meals and snacks. The diets are standardized and consumed during the assigned intervention period as part of the randomized crossover feeding trial.
• UPF Test Diet B: Meat, fish, and bread products (Other): The 2-week diet phase includes a standardized control run-in diet with non-UPFs only for 7 days, immediately followed by a 7-day UPF test diet with \~60% of calories from UPFs consisting of meat, fish, and bread products. Participants receive all study-provided meals and snacks. The diets are standardized and consumed during the assigned intervention period as part of the randomized crossover feeding trial.
• UPF Diet C: Dairy products, including cheese and cream (Other): The 2-week diet phase includes a standardized control run-in diet with non-UPFs only for 7 days, immediately followed by a 7-day UPF test diet with \~60% of calories from UPFs consisting of dairy products, including cheese and cream. Participants receive all study-provided meals and snacks. The diets are standardized and consumed during the assigned intervention period as part of the randomized crossover feeding trial.

Primary outcomes

• Within-person metabolomic response during each UPF test diet, compared to the paired non-UPF control diet. [Day 0, Day 7, and Day 14 of each dietary intervention period]: The primary outcome for this study is within-person metabolomic response during each UPF test diet, compared to the paired non-UPF control diet. Metabolomic responses will be quantified from metabolite concentrations (e.g., relative abundance) measured in fasting plasma samples collected at day 0, day 7, and day 14 in each diet phase.

Sex: All, ages: 20 Years to 65 Years, accepts healthy volunteers

Inclusion Criteria:

* Adults, ages 20 to 65 years.
* BMI 18.5 to 39.9 kg/m2.
* No known food allergies, intolerances, or sensitivities (e.g., gluten, dairy, monosodium-glutamate).
* Not following a restrictive diet for health, religious, or other reasons (e.g., vegetarian, vegan).
* Willingness to participate and give informed consent.
* Willingness to consume dietary intervention foods and beverages.

Exclusion Criteria:

* BMI <18.5 or >39.9 kg/m2.
* Pregnant, lactating, or planning on becoming pregnant in the next 6 months.
* History of bariatric surgery.
* Currently taking medications impacting appetite or body weight.
* History of major chronic diseases, including cardiovascular disease, type 1 or 2 diabetes, major gastrointestinal conditions, uncontrolled hypertension (seated blood pressure systolic >140 mmHg or diastolic >90 mmHg), history of invasive cancer, current use of immunosuppressants, and other major chronic diseases and conditions affecting participation, adherence, or study endpoints.
* Unwilling or unable to comply with all in person scheduled visits, dietary protocols, study protocol, and other study procedures.
* Food allergies or aversions to the foods provided in the dietary interventions.
* Non-English speaking.
* Other members of the same household are already participating in the research study.
* Planning on moving out of the Boston area in the next 6 months.

• Deirdre K Tobias, ScD, Principal investigator, Brigham and Women's Hospital
• Shilpa Bhupathiraju, PhD, Principal investigator, Brigham and Women's Hospital
• Frank B Hu, MD PhD, Principal investigator, Harvard School of Public Health (HSPH)

NIH grants: R01DK145733