Vegetable Consumption in Relation to Health
Condition: Health; Obesity; Oxidative Stress
MeSH terms: Obesity
Study type: Interventional

Summary: 
      Rationale: Consumption of vegetables is generally considered to be associated with several
      positive effects on health. Vegetables are a heterogeneous group of our diet which is rich in
      bio-actives. The vegetables contain a range of vitamins, minerals, dietary fibres and
      phytochemicals like potassium, flavonoids, carotenoids, and vitamin C. The recommended intake
      of vegetables by the Dutch Health Council is 200 grams daily (Health Council, 2006).

      Health in this project is defined as the possibility of a subject to change and adapt easily
      in response to a certain challenge. Healthy subjects show resilience in different
      physiological processes related to oxidative stress, metabolic stress, neurological stress
      and inflammatory stress. The reaction/response to a challenge might be changed when subjects
      have consumed more or less vegetables and have an improved health status. The response might
      also differentiate between subjects differing in BMI (healthy weight versus
      overweight/obese). Supplementation of vegetables will be provided in two conditions: a low
      and a high daily intake (50 versus 200 grams daily). An intervention known to have positive
      effects on health is weight loss. This will be studied in relation to health (the reaction to
      the challenge test) as well.

      A beneficial effect is present when 5% improvement of health markers is shown with vegetable
      supplementation, similar as is known from weight loss studies.

      Objective: The primary objective of the present study is to set-up a methodology to
      investigate health based on the resilience to challenge. A secondary objective is the
      effectiveness of the challenge concept with a food intervention. The vegetable
      supplementation study is a first example to test the challenge concept. Therefore, vegetable
      consumption according to the recommendations of the Dutch Health Council of 200 grams of
      vegetables daily will be studied with an exercise challenge test, to investigate the
      beneficial 'health' effects.
    

Detailed description: 
      Study design: The study is designed as a randomized, cross-over and parallel, open study.

      Study population: The number of subjects participating in the study will be 32, healthy, lean
      and obese men, aged between 18-45 years.

      Intervention: each intervention lasts four weeks:

        -  High Vegetable treatment: consumption of 200 grams of vegetables daily;

        -  Low Vegetable treatment: consumption of 50 grams of vegetables daily;

        -  An energy restricted diet intervention with the habitual vegetable consumption.

      Main study parameters/endpoints: A 'challenge test' will be used as a physical stress test to
      examine whether subjects show more or less resilience to the test. The reaction and recovery
      of the human system to the exercise test may be used as indicators of health status on
      different biological analyses (transcriptomics; metabolomics; rules based medicine pm).
      Different analyses to measure oxidative stress will be performed. Also standard health
      biomarkers will be determined to examine the intervention effects.
    

Intervention name(s): Vegetables; energy restriction
Intervention type(s): Dietary Supplement; Dietary Supplement
Intervention description(s): 200 or 50 grams of vegetables daily for four weeks; Consume about 1000 kcal less daily, for four weeks, as a positive control to the vegetables interventions.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Basic Science
Keywords: Health; Obesity; Oxidative stress; Challenge concept; Vegetables