Sustainable Diets and Cardiometabolic Health

Condition(s) studied

Investigational drug(s) / intervention(s)

Dietary advice (PHD): It consists of a written document outlining the PHD diet recommendations. Participants will receive: 1) information about the PHD guidelines by EAT-Lancet (a high-quality plant-based diet with a low allowance of intake of eggs, dairy, chicken, and fish, but strictly avoiding red and processed meat) adapted to be nutritionally adequate and culturally accepted in Denmark, 2) a meal planner for their calorie demands (templates for 2000 kcal/day; 2500 kcal/day; and 3000 kcal/day), 3) guidance on alternatives for substituting meat when cooking at home or eating out, and 4) information on seasonal fruits and vegetables. The meal planner will specify the amounts of eggs, dairy, chicken, and fish that each participant should consume based on their total energy demands. The PHD dietary advice focuses on limiting certain food groups (without excluding them) based on their health and environmental impact.

Dietary advice (Ovo-lacto-vegetarian diet): It consists of a written document outlining the ovo-lacto-vegetarian diet guidelines. Participants will receive information to adhere to a stricter plant-based diet with an intake of eggs and dairy, but avoiding chicken, fish, and red and processed meat, and guidance on alternatives for substituting meat when cooking at home or eating out. Recommendations on food quantity or on consuming local and seasonal foods will not be given to pinpoint differences in the environmental aspect between interventions.

Dietary advice (control): It consists of a written document outlining the general recommendations of a healthy diet (i.e. consumption of fruits and vegetables, decreasing the intake of sugar-sweetened beverages, etc.) without any specific advice on the consumption of animal products.

Behavioural support PHD: This component is designed to help participants adhere to the PHD through four individual and personalized dietary visits with a dietitian. Participants will also have access to a digital recipe collection in the study app. Recipes will be tagged by meal type and by season.

Food boxes PHD: Food boxes will be sent to participants' homes. PHD food boxes will include seasonal and local fruits and vegetables, whole grain products, legumes, nuts, and dairy or milk alternatives. If allergies or intolerances are identified, the food boxes will be modified to maintain safety and dietary compliance.

Group visits PHD: Group visits will provide support through nutritional education, social interaction, and peer learning, all focused on the dietary behavior changes required by the intervention. PHD group visits will cover topics such as PHD principles, and the related environmental and health outcomes.

Behavioural support (Ovo-lacto-vegetarian diet): This component is designed to help participants adhere to the ovo-lacto-vegetarian through four individual and personalized dietary visits with a dietitian. Participants will also have access to a digital recipe collection in the study app. Recipes will be tagged by meal type.

Food boxes (Ovo-lacto-vegetarian diet): Food boxes will be sent to participants' homes. Ovo-lacto-vegetarian food boxes will include fruits and vegetables, whole grains, legumes, nuts, soy-based products, eggs, and cheese. Local and seasonal aspects will not be taken into consideration. If allergies or intolerances are identified, the food boxes will be modified to maintain safety and dietary compliance.

Group visits (Ovo-lacto-vegetarian diet): Group visits will provide support through nutritional education, social interaction, and peer learning, all focused on the dietary behavior changes required by the intervention. Ovo-lacto-vegetarian group visits will cover topics such as plant-based eating and nutritional adequacy.

Behavioral support (control): Participants will attend four short individual dietary visits with a dietitian, where they will review the recorded dietary data. Participants of the control group will not have access a recipe collection or meal planner.

Food boxes (control): Food boxes will be sent to participants' homes. Control food boxes will include fruits and vegetables, potato, nuts, cheese, animal protein products and canned food. Local and seasonal aspects will not be taken into consideration. If allergies or intolerances are identified, the food boxes will be modified to maintain safety.

Group visits (control): Group visits will provide support through general health education, social interaction, and peer learning. Control group visits will cover topics such as the role and importance of controls in RCTs and general well-being.

Study summary

This study aims to investigate the effects of sustainable diets on traditional and novel cardiometabolic risk factors.

The primary objective is:

• To test the effects of a sustainable diet on traditional cardiometabolic risk factors, specifically, a metabolic health score.

The secondary objectives are:

* To test the effects of sustainable diets on blood lipids, inflammatory markers, glucose markers, and anthropometric and body composition markers.
* To test the effect of sustainable diets on circulating metabolomic profiles.
* To test the effects of sustainable diets on circulating proteomic profiles.

Participants will receive dietary interventions of a sustainable health diet, namely the PHD diet (Planetary Health Diet), an ovo-lacto-vegetarian diet, or a habitual diet following general recommendations for a healthy diet without advice on consumption of animal products. The three-arm parallel RCT will involve adults (45-70 years old) at cardiovascular risk.

The primary hypothesis is that targeted interventions to adopt sustainable diets will have beneficial effects on cardiometabolic biomarkers, metabolomic, and proteomic profiles, compared to the habitual diet in individuals at cardiovascular risk.

Eligibility

Primary outcome measure(s)

• Changes in metabolic health score — Baseline, 3 and 6 months
  A metabolic health score that summarizes clinical biomarkers from main pathways associated with CVD: triglycerides, HDL-c, fasting plasma glucose, systolic and diastolic blood pressure, and high sensitive C-reactive protein (hs-CRP) (as a marker of inflammation). A Z-score will be calculated for each variable. HDL-cholesterol standardized values will be multiplied by -1 to be directly proportional to the cardiometabolic risk. The final score will be determined as the average of the individual component Z-scores. Thus, the metabolic health score is a continuous variable with a mean of 0 and a standard deviation of 1; higher scores indicate higher risk

Trial sites (1)

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