The study aims to study the impact of frequent intake of 150-180 gram duckweed on gastrointestinal complaints and several other health related biomarkers. The study has a randomised parallel design. Two different treatments will be evaluated e.g. a 11-day intervention with duckweed based meals and a 11-day intervention with control/spinach meals. At the start and at the end of the intervention we will collect a blood sample and a urine samples. Questionnaires about gut complaints, stool consistency and frequency, wellbeing, health complaints or other adverse effects will be collected daily during intervention and up to two days after the intervention.

The study aims to study the impact of frequent intake of 150-180 gram duckweed on gastrointestinal complaints and several other health related biomarkers.

Objective: The primary objective is to investigate gastro-intestinal complaints during 11 day duckweed consumption. Secondary objectives are to assess blood based parameters related to general health and urine based biomarkers for kidney function and to investigate consumer acceptance.

Study design: The study has a randomised parallel design. Two different treatments will be evaluated e.g. a 11-day intervention with duckweed based meals and a 11-day intervention with control/spinach meals. At the start and at the end of the intervention we will collect a blood sample and a urine samples. Questionnaires about gut complaints, stool consistency and frequency, wellbeing, health complaints or other adverse effects will be collected daily during intervention and up to two days after the intervention.

Study population: We aim to include 24 healthy volunteers aged 18-50 years. Intervention: A 11-day intervention in which subjects will receive a daily lunch with 150-180g wet weight duck weed or spinach. Products will be incorporated in food products such as pasta, curry, soup etc.

Main study parameters/endpoints: The main study parameter is frequency and severity of gastro-intestinal complaints. Secondary outcomes are intestinal health parameters derived from blood and urine samples taken before and after the intervention.

Inclusion criteria

• Apparently healthy men and women
• Age between 18 and 50 years
• Body mass index (BMI) between 18.5 and 24.9 kg/m2

Exclusion criteria

• Any metabolic, gastrointestinal, inflammatory or chronic disease (such as diabetes, anaemia, hepatitis, cardiovascular disease)
• History of gastro-intestinal surgery or having (serious) gastro-intestinal complaints
• History of liver dysfunction (cirrhosis, hepatitis) or liver surgery
• Kidney dysfunction (self-reported)
• Use of medication that may influence the study results, such as gastric acid inhibitors or laxatives
• Reported slimming, medically prescribed or vegan/vegetarian diet
• Current smokers
• Alcohol intake ≥4 glasses of alcoholic beverages per day
• Pregnant, lactating or wishing to become pregnant in the period of the study (self-reported)
• Abuse of illicit drugs
• Food allergies for products that we use in the study
• Participation in another clinical trial at the same time
• Being an employee of the department Consumer Science & Health group of Wageningen Food & Biobased Research

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