The purpose of this study is to assess the effects of carotenoids from natural carrot juice on the immune system. Therefore, the study aims to distinguish the effects of natural juices that are rich in phytonutrients such as carotenoids in healthy and depressive individuals, to explore their potential use in therapeutic settings. The consumption of natural fruit juices rich in polyphenols and carotenoids serves as a model for a vegetarian diet, due to the increased micronutrient density derived from plant-based foods. The results obtained may provide preliminary explanatory models for the beneficial effects of a vegetarian diet. It is hypothesized that the consumption of a natural carotenoid-rich juice alters the expression of regulatory T cells-specific immune cells that contribute to immunomodulation. Furthermore, beneficial changes in the gut microbiome, metabolome, and nutritional status are expected. This study was registered retrospectively (after recruitment had started) on ClinicalTrials.gov.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
NONE
Enrollment
120
The intervention is based on the additional consumption of 200 ml natural carotneoid-rich juice a day for a period of six weeks. The participants are asked to drink the natural and commercially available juice in addition to their regular diet. Further, they are asked not to change their diets and lifestyle behaviour during the intervention.
Participants assigned to the control group are asked to drink additional 200ml of water a day to control liquid intake.
Medical Universtiy of Graz
Graz, Styria, Austria
Change of baseline regulatory T cells (Tregs) at week 6 (after the intervention) and after a wash-out period at week 12.
Tregs are involved in modulating the immune system and maintaining tolerance to self-antigens and preventing autoimmune diseases. Regulatory T cells (Treg) will be quantified using multiparameter flow cytometry. Monoclonal antibodies specific for surface markers such as CD3, CD4, CD45RA, CD39 and CD25 will be combined with intracellular anti-Foxp3 for the identification of human Treg. Tregs are involved in modulating the immune system and maintaining tolerance to self-antigens and preventing autoimmune diseases. The assessment of Tregs after 12 weeks aims to identify any persisting effects of the intervention.
Time frame: From enrollment (baseline) to the end of intervention at week 6 and after a wash-out period at week 12.
Effect of carotenoid-rich juice consumption on gut microbiota composition, assessed by changes in alpha diversity (Shannon Index) between intervention and control groups.
Time frame: From enrollment (baseline) to the end of intervention at week 6 and after a wash-out period at week 12.
Change in plasma carotenoid concentration following carotenoid-rich juice consumption, compared between intervention and control groups.
Carotenoid plasma concentration is quantified by High-Performance Liquid Chromatography (HPLC).
Time frame: From enrollment (baseline) to the end of intervention at week 6 and after a wash-out period at week 12.
Change in skin carotenoid levels (measured non-invasively), following carotenoid-rich juice consumption, compared between intervention and control groups.
Skin carotenoid score is determined on an arbitrary scale non-invasively by spectroscopic devices (Veggimeter and Biozoom). A higher score indicates higher carotenoid content stored in the skin (Score Ranges: Biozoom 0-12M; Veggimeter 0-800).
Time frame: From enrollment (baseline) to the end of intervention at week 6 and after a wash-out period at week 12.
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