An interventional study of Group 1, hydroxytyrosol-rich extract capsule and Group 2, capsule of placebo in Overweight and PreDiabetes, sponsored by National Research Council, Spain. Completed at 1 site in Spain. Open to participants aged 40 Years to 75 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2025-02-12.
Sponsored by National Research Council, Spain · Not applicable, Interventional, and Basic science
The primary objective of this study is to ascertain the effects of chronic consumption of a hydroxytyrosol-rich extract from olive in a population at high risk of developing age-related pathologies such as type 2 diabetes and cardiovascular diseases. The markers measured will be associated with oxidative stress, inflammation, and homeostasis glucose and lipid profiles. Improvements in these parameters could potentially prevent the onset of pathologies associated with aging.
Fifty subjects 40-75 years old overweight (BMI between 24-29,9 kg/m2) and prediabetes (fasting blood sugar between 100-126 mg/dl and/or glycated hemoglobin between 5,7-6,4%) will be recruited. Detailed inclusion and exclusion criteria are provided below.
Participants will be randomly divided into two groups, one to consume the Hytolive® capsule and the other a placebo. The intervention study has been designed for daily consumption before breakfast of one capsule for 16 weeks. The study includes a two-week washout period during which subjects will not be allowed to consume olives or virgin olive oil.
At the beginning and end of the study, upon arrival at the ICTAN-CSIC Human Nutrition Unit, volunteers will provide a urine sample corresponding to the first morning void, and a nurse will draw a fasting blood sample (20 mL distributed in tubes with various anticoagulants for measurements). Additionally, their blood pressure will be measured, and a complete anthropometric and body composition study will be conducted. Furthermore, volunteers will provide a stool sample from the preceding days (these samples will not be used in this study but will be stored at -80°C for potential future determination of the intestinal microbiota metagenomic profile). Subsequently, dietary controls will be conducted, physical activity and emotional well-being tests will be administered, and fatigue will be evaluated. Additionally, there will be an interim visit aimed at verifying adherence to supplementation. For this purpose, volunteers will provide a urine sample corresponding to the first morning void on an empty stomach, in which levels of hydroxytyrosol and its derivatives will be determined. Likewise, dietary and physical activity controls will be conducted to confirm that volunteers are not altering their habits.
3,599 studies on the registry are indexed under Overweight; 852 are open to participants now.
This study's enrollment of 49 is below the median of 78 across 3,120 interventional studies indexed under Overweight.
Browse Overweight studies →National Research Council, Spain is the lead sponsor of 28 studies on the registry; 1 is open to participants now.
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Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
A blood test of average blood sugar over the past two to three months, given as a percentage or in mmol/mol. 6.5% (48 mmol/mol) or more is the usual threshold for diabetes, normally confirmed by a second test.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
HbA1c
A blood test of average blood sugar over the past two to three months, given as a percentage or in mmol/mol. 6.5% (48 mmol/mol) or more is the usual threshold for diabetes, normally confirmed by a second test.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HIV
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Intake of one capsule/day containing 15 mg of hydroxytyrosol before breakfast for 16 weeks.
Dietary Supplement: Group 1, hydroxytyrosol-rich extract capsule
Intake of one capsule placebo/day without hydroxytyrosol before breakfast for 16 weeks.
Dietary Supplement: Group 2, capsule of placebo
Following a two-week washout period, the subjects will receive a bottle containing capsules (Group 1). Blood, urine, and fecal samples will be collected from each participant during their stay at the Human Nutrition Unit at the beginning and end of the study. Subjects will be instructed to refrain from consuming products rich in hydroxytyrosol (such as virgin olive oil and olives) and to maintain their usual dietary habits throughout the study. Additionally, olive oil (1L/week) will be provided to each volunteer that will consume during intervention study as the sole source of dietary fat, used for cooking, salad dressing, toasts, etc. in order to control the extra consumption of hydroxytyrosol apart from that provided by the capsule.
Following a two-week washout period, the subjects will receive a bottle containing capsules (Placebo) (Group 2). Blood, urine, and fecal samples will be collected from each participant during their stay at the Human Nutrition Unit at the beginning and end of the study. Subjects will be instructed to refrain from consuming products rich in hydroxytyrosol (such as virgin olive oil and olives) and to maintain their usual dietary habits throughout the study. Additionally, olive oil (1L/week) will be provided to each volunteer that will consume during intervention study as the sole source of dietary fat, used for cooking, salad dressing, toasts, etc. in order to control the extra consumption of hydroxytyrosol.
LDL-ox as marker of oxidative status
Differences between subjects supplemented with hydroxytyrosol and non-supplemented subjects
Time frame: Up to six months
Mental well-being determined by Warwick-Edinburgh Mental Well-being Scale
Differences between subjects supplemented with hydroxytyrosol and no-supplemented subjects
Time frame: Up to two months
Sleep quality determined by Pittsburgh Sleep Quality Index
Differences between subjects supplemented with hydroxytyrosol and no-supplemented subjects
Time frame: Up to two months
Fatigue test determined by Borg Rating Of Perceived Exertion
Differences between subjects supplemented with hydroxytyrosol and no-supplemented subjects
Time frame: Up to two months
Fasting glucose
Differences between subjects supplemented with hydroxytyrosol and no-supplemented subjects
Time frame: Up to six months
Fasting insulin
Differences between subjects supplemented with hydroxytyrosol and no-supplemented subjects
Time frame: Up to six months
Glycated hemoglobin (HbA1c)
Differences between subjects supplemented with hydroxytyrosol and no-supplemented subjects
Time frame: Up to six months
Glucagon-like peptide-1 (GLP-1)
Differences between subjects supplemented with hydroxytyrosol and no-supplemented subjects
Time frame: Up to six months
Total cholesterol
Differences between subjects supplemented with hydroxytyrosol and no-supplemented subjects
Time frame: Up to six months
High density lipoproteins (HDL)
Differences between subjects supplemented with hydrpxytyrosol and no-supplemented subjects
Time frame: Up to six months
Low density lipoproteins (LDL)
Differences between subjects supplemented with hydroxytyrosol and no-supplemented subjects
Time frame: Up to six months
Triglycerides
Differences between subjects supplemented with hydroxytyrosol and no-supplemented subjects
Time frame: Up to six months
Apoliporpotein A1
Differences between subjects supplemented with hydroxytyrosol and no-supplemented subjects
Time frame: Up to six months
Apoliporpotein B
Differences between subjects supplemented with hydroxytyrosol and no-supplemented subjects
Time frame: Up to six months
Total antioxidant status (TAS)
Differences between subjects supplemented with hydroxytyrosol and no-supplemented subjects
Time frame: Up to six months
Total oxidative status (TOS)
Differences between subjects supplemented with hydroxytyrosol and no-supplemented subjects
Time frame: Up to six months
Oxides of nitrogen (NOx)
Differences between subjects supplemented with hydroxytyrosol and no-supplemented subjects
Time frame: Up to six months
Thiobarbituric acid reactive substances (TBARS)
Differences between subjects supplemented with hydroxytyrosol and no-supplemented subjects
Time frame: Up to six months
C reactive protein
Differences between subjects supplemented with hydroxytyrosol and no-supplemented subjects
Time frame: Up to six months
Interleukine 6 (IL-6)
Differences between subjects supplemented with hydroxytyrosol and no-supplemented subjects
Time frame: Up to six months
Tumor necrosis factor alpha (TNF-α)
Differences between subjects supplemented with hydroxytyrosoland no-supplemented subjects
Time frame: Up to six months
Alanine aminotransfesare (transaminases ALT)
Differences between subjects supplemented with hydroxytyrosol and no-supplemented subjects
Time frame: Up to six months
Aspartate aminotransferase (transaminase AST)
Differences between subjects supplemented with hydroxytyrosol and no-supplemented subjects
Time frame: Up to six months
Plan to share: No
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National Research Council, Spain