The Effects of Agro-ecological Farming Systems on Human Health

The Effects of Agro-ecological Farming Systems on Human Health -- A Randomized Controlled Trial of Agro-ecologically vs Conventionally Produced Foods on Human Health Biomarkers

As concerns regarding the effects of agriculture on human and environmental health mount, a growing number of farmers are seeking ways to improve health from the ground up. A promising way by which a growing number of farmers are seeking to improve environmental health is by using agro-ecological practices (i.e., farming more closely in harmony with natural systems), which include practices such as multi-cropping, ley rotations, and/or integrated crop-livestock systems. Despite potential ecological benefits, there is a lack of critical knowledge if consuming foods from agro-ecological systems impacts biomarkers of human health, including inflammatory and metabolomics profiles. The purpose of this project is to test the hypothesis that consuming foods produced using agro-ecological practices improves biomarkers of consumer health compared to consuming similar foods from conventional (monoculture) agriculture. All diets will be matched one-to-one in terms of macronutrients and food sources.

This work will utilize a randomized cross-over design to compare an agroecological vs conventional sourced diet, and determine their effects on inflammation and cardio metabolic health signatures in middle-aged adults (35-60 y old). Diets will be isocaloric and matched for macronutrient content, and consumed for 44 days each with a 14-day washout (habitual diet) period in between. Blood, urine, and stool samples will be obtained before and after the dietary interventions, in addition to data about physical activity and questionnaires regarding quality of life.

STUDY OBJECTIVES

1. To determine the effects on plasma inflammatory markers (IL-6, TNF-α, C-reactive protein) in response to each intervention.
2. To determine effects on urinary and plasma metabolites (vitamin and mineral derivatives, polyphenols, amino acids, glucose metabolites etc.) to provide insight into metabolic health pathways in response to each intervention.
3. To determine effects on gut microbiota communities (alpha and beta diversity, and short-chain fatty acid producing bacteria) in response to each intervention.

INTERVENTION

After completing all baseline testing, participants will be randomized to one of the two starting diets (agroecological or conventional, for 44 days with a 14 day washout period until they start their second diet (agroecological or conventional depending on the starting diet). In accordance with established protocols, a research dietitian will provide weight-maintenance diets based on each individual's daily energy requirement (Harris-Benedict equation). All foods that participants consume during those 44 days will be provided by the Metabolic Kitchen at NDFS, and dietitian-led group classes and handouts with food preparation instructions will be provided to the participants to ensure compliance. The diets will be provided as 4-day rotating menus and participants will be asked to pick-up food twice weekly at the NDFS building. This will allow the research time to interact face-to-face with the participant, address any issues, and further ensure compliance. All subjects assigned to the same diet will receive identical meals and snacks, but portion sizes will be determined based on the previously mentioned daily energy requirement. Food for the agroecological diet will be sourced predominantly from the Greenacres farm (Cincinnati, OH) and/or other producers that use documented agro-ecological principles (e.g., Regenerative Organic Certified). Food for the conventional diet will be sourced from local grocery stores in Logan, UT (non-organic produce). All foods will be stored in food-grade fridges and freezers in the CHNS Metabolic Kitchen and food boxes will be prepared weekly by staff.

Examples of Meals

Breakfast Whole milk, eggs, oatmeal, and blueberries

Snack Rice cakes

Lunch Ground beef, tomato salad and cherries

Snack Apple with nut butter

Dinner Grilled chicken with rice and steamed broccoli

Inclusion Criteria:

• Age ≥35 and ≤60 years
• BMI ≥25 and ≤35kg/m2
• Weight stable in last 3 months (loss or gain <4%)
• Hemoglobin A1C (HbA1C ≤6.4%)
• Fasting plasma glucose concentration <126mg/dl
• For the safety of the participant and proper consent of the procedures, subjects must be able to speak and understand English to participate in this study
• Stable medication/supplement use for 3 months prior to study

Exclusion Criteria:

• Use of medications that are known to affect the study outcome measures (e.g., NSAIDs, corticosteroids) or increase the risk of study procedures (e.g., anticoagulants) that cannot be temporarily discontinued for this study
• Strict dietary patterns (e.g., vegan, keto)
• Consuming >14 alcoholic drinks per week
• Use of cigarettes (or other tobacco products) in last 3 months
• Engaged in high level of competitive exercise (e.g., iron man, marathons, powerlifting)
• Diagnoses of active malignancy, congestive heart failure, diabetes mellitus or chronic obstructive pulmonary disease
• Any inflammatory diseases(e.g., autoimmune diseases, coeliac disease, glomerulonephritis, hepatitis, inflammatory. bowel disease, arthritis)
• Use of antibiotics in last 60 days
• Pregnant or planning to become pregnant in the next 5 months
• Lactating women
• Persons who are unable or unwilling to follow the study protocol or who, for any reason, the research team considers not an appropriate candidate for this study, including non-compliance with screening appointments or study visits
• Participants that are pregnant or planning on becoming pregnant in the next 5 months are excluded. The justification is the documented alterations in metabolism that occur during pregnancy, which would impact our metabolomics analysis in this study.