Acute Metabolic Response Versus Long-term Adaptation to a Vegan Diet

NCT07731633 | Completed

• 1 other identifier: EK 73/2022
• Study Type: interventional
• Target: 31
• Locations: 1 country
• Sites: 1

Brief Summary

At baseline, venous blood samples were collected from all eligible participants. The following biochemical parameters were analysed: serum electrolytes (mineral profile), fasting glucose, creatinine, urea nitrogen, total proteins, albumin, bilirubin, liver enzymes, C-reactive protein (CRP), total cholesterol, triacylglycerols (TAG), serum iron, active vitamin D, vitamin B12, complete blood count. At baseline, all participants also underwent standardized anthropometric measurements, including height (cm), body weight (kg) and BMI was calculated accordingly. Body composition was assessed using bioelectrical impedance analysis with the InBody Tanita MC-780MA device. The following parameters were recorded: total body fat (kg, %), visceral fat (kg, %), skeletal muscle mass (kg, %), total muscle mass (kg, %), total body water (kg, %), sarcopenic index (kg/m²), phase angle. To assess health-related quality of life and symptom burden, all participants completed validated questionnaires: World Health Organization Quality of Life - Brief Version (WHOQOL-BREF), Patient Assessment of Gastrointestinal Disorders - Symptom Severity Index (PAGI-SYM), Patient-Reported Outcomes Measurement Information System Global Health-10 (PROMIS-10), Patient Assessment of Upper Gastrointestinal Disorders - Quality of Life (PAGI-QoL) and Patient Health Questionnaire-15 (PHQ-15). After the one-month intervention, participants in the VEG group repeated laboratory testing, anthropometric assessment, body composition analysis, and questionnaire evaluation. The same follow-up assessments were performed in the WD group for comparative purposes. Long-term vegans (VEG-P) did not undergo repeated measurements. Dietary Monitoring and Adherence At study enrolment, all participants were offered a dietary consultation to improve adherence to the assigned dietary regimen. Participants were also instructed to maintain a food diary throughout the study period, which was periodically reviewed via telephone or email consultation.

Conditions

Vegan Diet; Body Composition; Quality of Life (QOL); Cardiometabolic Health

Keywords

vegan diet; dietary intervention; body composition; metabolic adaptation; quality of life

Outcome Measures

Primary Outcomes (6)

• The difference in body weight (kg), between healthy vegans (more than 2 years) and omnivores.

  To comprehensively compare body weight among individuals following different dietary patterns (long-term vegans and omnivores).

  Baseline

• The difference in body weight (kg) between omnivores and intervention group (omnivores transitioned to vegan diet).

  To comprehensively compare body weight among individuals following different dietary patterns (long-term omnivores and intervention group).

  From baseline to the end of intervention at 4 weeks

• The difference in lipid profile (total cholesterol, triglycerides), between healthy vegans (more than 2 years) and omnivores.

  At baseline, venous blood samples were collected from all eligible participants to analyse lipid profile: total cholesterol (mmol/l), triaglycerides (mmol/l).

  Baseline

• The difference in C-reactive protein (CRP), between healthy vegans (more than 2 years) and omnivores.

  At baseline, venous blood samples were collected from all eligible participants to analyse CRP (mg/l).

  Baseline

• The difference in lipid profile (total cholesterol, triglycerides) between omnivores and intervention group (omnivores transitioned to vegan diet).

  To comprehensively compare lipid profile parameters among individuals following different dietary patterns (long-term omnivores and intervention group). Venous blood samples were analyzed to measure total cholesterol (mmol/l) and triglycerides (mmol/l).

  From baseline to the end of intervention at 4 weeks

• The difference in C-reactive protein (CRP) between omnivores and intervention group (omnivores transitioned to vegan diet).

  To comprehensively compare CRP parameters among individuals following different dietary patterns (long-term omnivores and intervention group). Venous blood samples were analyzed to measure CRP (mg/l).

  From baseline to the end of intervention at 4 weeks.

Secondary Outcomes (5)

• World Health Organization Quality of Life - Brief Version (WHOQOL-BREF)

  From baseline to the end of intervention at 4 weeks

• Patient Assessment of Gastrointestinal Disorders - Symptom Severity Index (PAGI-SYM).

  From baseline to the end of intervention at 4 weeks.

• Patient-Reported Outcomes Measurement Information System Global Health-10 (PROMIS-10).

  From baseline to the end of intervention at 4 weeks.

• Patient Assessment of Upper Gastrointestinal Disorders - Quality of Life (PAGI-QoL).

  From baseline to the end of intervention at 4 weeks.

• Patient Health Questionnaire-15 (PHQ-15).

  From baseline to the end of intervention at 4 weeks.

Study Arms (1)

VEG

EXPERIMENTAL

omnivores transmitted to vegan diet

Dietary Supplement: vegan diet

Interventions

vegan diet DIETARY_SUPPLEMENT

omnivores transmitted to vegan diet

VEG

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Age ≥ 18 years
• Healthy individuals without chronic disease
• BMI between 18 and 30 kg/m²
• Provision of written informed consent
• For the VEG-P group: exclusive adherence to a plant-based diet for at least 2 years
• For the WD group: regular consumption of animal products for at least 2 years

You may not qualify if:

• Active infection
• Eating disorder
• Severe or unstable metabolic disease (e.g., diabetes mellitus)
• Endocrine disorders
• BMI \< 18 or \> 30 kg/m²
• Age \< 18 years
• Current or past malignancy
• Systemic corticosteroid therapy
• Hormone replacement therapy
• Pregnancy
• Inability to complete follow-up assessments
• Excessive alcohol consumption

Sponsors & Collaborators

• University Hospital, Martin: lead

Study Sites (1)

University Hospital Martin

Martin, Žilina Region, 03601, Slovakia

Location

MeSH Terms

Interventions

Diet, Vegan

Intervention Hierarchy (Ancestors)

Diet, Vegetarian; Diet, Plant-Based; Diet Therapy; Nutrition Therapy; Therapeutics; Diet; Nutritional Physiological Phenomena; Diet, Food, and Nutrition; Physiological Phenomena

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NA
• Masking: NONE
• Purpose: PREVENTION
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Investigator

Study Record Dates

• First Submitted: July 15, 2026
• First Posted: July 28, 2026
• Study Start: February 16, 2023
• Primary Completion: June 5, 2024
• Study Completion: June 5, 2024
• Last Updated: July 28, 2026

Record last verified: 2026-07

Locations

SL (1)