Mono-centred, randomised, placebo-controlled, double-blind parallel-arm study on the effect of Conjugated Linoleic Acid (CLA) on endothelial function and (postprandial) metabolic parameters in overweight men

ISRCTN	ISRCTN30870177
DOI	https://doi.org/10.1186/ISRCTN30870177
Secondary identifying numbers	N/A

Submission date: 03/09/2008
Registration date: 17/10/2008
Last edited: 03/01/2012

Recruitment status: No longer recruiting
Overall study status: Completed
Condition category: Circulatory System

Prospectively registered

Protocol

Statistical analysis plan

Results

Individual participant data

Plain English summary of protocol

Not provided at time of registration

Contact information

Prof Juergen Schrezenmeir
Scientific

Max Rubner-Institute
Federal Research Centre for Nutrition and Food
Hermann-Weigmann-Str. 1
Kiel
24103
Germany

Phone	+49 (0)431 609 2220
Email	juergen.schrezenmeir@mri.bund.de

Study information

Study design	Single centre, randomised double-blind placebo-controlled intervention study
Primary study design	Interventional
Secondary study design	Randomised controlled trial
Study setting(s)	Not specified
Study type	Treatment
Scientific title
Study acronym	CLA1
Study objectives	Conjugated linoleic acid (CLA) may beneficially affect lipid and glucose metabolism, inflammatory responses and body weight. These aspects are of relevance for subjects afflicted with or prone to develop a so-called metabolic syndrome, which is characterised by an insulin resistance, dyslipidaemia, essential hypertension and adiposity of the central type and frequently leads to early manifestation of type 2 diabetes mellitus, increased vascular risk and risk of atherosclerosis. This study examines the influence of dietary conjugated linoleic acid (CLA) (commercially available 50:50 mixture of isomers cis9,trans11-CLA and trans10,cis12-CLA) on endothelial function and below mentioned fasting and postprandial metabolic parameters in comparison to safflower oil. For explorative purposes two more groups are given native olive oil or heated (thermally oxidised) safflower oil. Tocopherol concentration of the supplements is adjusted to that of safflower oil. Further parameters to judge pro-atherogenic processes are soluble adhesion molecules (intercellular adhesion molecule [ICAM], vascular cell adhesion molecule [VCAM], E-Selectin) which promote inflammatory processes by initiating the adherence of leukocytes and monocytes to the endothelium of blood vessels.
Ethics approval(s)	Ethics approval received from the Ethics Committee of the Medical Faculty of the Christian-Albrechts-University of Kiel (Germany) on the 13th April 2006 (ref: A 106/06)
Health condition(s) or problem(s) studied	Cardiovascular disease
Intervention	Group 1: CLA 50:50 isomer mixture (cis9,trans11-CLA: trans10,cis12-CLA) Group 2: safflower oil Group 3: native olive oil Group 4: safflower oil - thermally oxidised Supplements given two times a day during breakfast (or lunch) and dinner, four capsules each, making a total dose per day of eight capsules (= 4.5 g). Total duration of treatment was 4 weeks (28 + 2 days), for all four treatments. Follow up: Start of the follow up period, i.e. start of the intervention for the first study subjects was 24/04/2006. End of the trial follow-up period was 02/08/2006.
Intervention type	Drug
Pharmaceutical study type(s)
Phase	Not Specified
Drug / device / biological / vaccine name(s)	Conjugated linoleic acid (CLA), safflower oil, native olive oil
Primary outcome measure	Changes in endothelial function: PAT-Index after 28(± 2) days supplementation.
Secondary outcome measures	1. Body mass index (BMI) 2. Waist circumference (WC) 3. Waist to hip ratio (WHR) 4. Blood pressure, pulse Changes in: 5. Fasting and postprandial triglycerides (AUC) 6. Fasting and postprandial insulin (AUC) 7. Fasting and postprandial glucose (AUC) 8. Homeostasis model assessment of insulin resistance (HOMA-IR) (insulin-glucose-product) 9. HOMA-b-cell-function 10. Lipids, namely total, low density lipoprotein (LDL-) and high density lipoprotein (HDL-) cholesterol 11. Oxidative modification of lipids and oxidative stress, namely: oxidised LDL, isoprostanes 13. Inflammatory parameters, namely: C-reactive protein (CRP), soluble vascular cell adhesion molecule (sVCAM), soluble intercellular adhesion molecule (sICAM), soluble E-selectin, interleukin-6 (IL-6), tumour necrosis factor alpha (TNF alpha), monocyte chemoattractant protein-1 (MCP-1) 14. Other regulators/hormones: adiponectin, leptin, ghrelin, glucagon-like peptide 1 (GLP-1), cholecystokinin (CCK), vascular endothelial growth factor (VEGF) All secondary parameters were determined both at start of the intervention (day 0) and end of the study, i.e. after 4 weeks. Treatment-induced changes were calculated and compared between intervention groups.
Overall study start date	18/04/2006
Completion date	02/08/2006

Eligibility

Participant type(s)	Patient
Age group	Adult
Sex	Male
Target number of participants	88
Key inclusion criteria	1. Healthy male volunteers 2. Aged 45 - 68 years 3. Body mass index (BMI) 25 - 29 kg/m^2 4. Member of the Metabolic Intervention Cohort Kiel (MICK) 5. Written informed consent
Key exclusion criteria	1. Participation in a clinical study with a medicament or a medicinal product within the last 30 days or simultaneous participation in another clinical examination 2. Inability to understand and to comply with the study protocol 3. Known metabolic or gastro-intestinal diseases, which affect the absorption, metabolism or excretion of food or food components 4. Condition after surgery of the gastro-intestinal tract, which affects gastro-intestinal motility 5. Haemoglobin less than 12 g/dL 6. Latex allergy 7. Diabetes (fasting glucose levels greater than 125 mg/dl after repeated determination) 8. Surgery within the last 3 months, which still affects the current state of health 9. Intake of nitrate and/or calcium antagonists, which affect the blood pressure 10. Deformation of finger tips, which inhibits correct recording of EndoPAT (measures a Peripheral Arterial Tone [PAT™] signal for assessment of endothelial dysfunction) 11. Illness of thyroid gland, which has metabolic and/or cardiovascular effect 12. Known hepatitis B, hepatitis C, human immunodeficiency virus (HIV) infection or chronic liver disease 13. Kidney malfunction 14. Psychiatric disorders, epilepsy, risk of suicide 15. Drug or alcohol abuse 16. Intake of drugs affecting the absorption, metabolism or excretion of food components or the gastro-intestinal motility 17. Intake of hormone preparations, particularly cortisone 18. Eating disorders, anorexia, bulimia, unusual outsider dietary habits 19. Legal incapacity 20. Others depending on the judgement of the study physician
Date of first enrolment	18/04/2006
Date of final enrolment	02/08/2006

Locations

Countries of recruitment

Germany

Study participating centre

Max Rubner-Institute

Kiel
24103
Germany

Sponsor information

Max Rubner Institute (Germany)
Research organisation

c/o Prof. Juergen Schrezenmeir
Federal Research Centre for Nutrition and Food
Haid-und-Neu-Str. 9
Karlsruhe
76131
Germany

Phone	+49 (0)721 6625 400
Email	pbe.kiel@mri.bund.de
Website	http://www.bfel.de
"ROR"	https://ror.org/045gmmg53

Funders

Funder type

Government

Federal Ministry of Education and Research (Bundesministerium für Bildung und Forschung [BMBF]) (Germany)
Government organisation / National government

Alternative name(s): Federal Ministry of Education and Research, BMBF
Location: Germany

Federal Ministry of Food, Agriculture and Consumer Protection (Bundesministerium für Ernährung, Landwirtschaft und Verbraucherschutz) (Germany)

No information available

Cognis GmbH (Germany)

No information available

Results and Publications

Intention to publish date
Individual participant data (IPD) Intention to share	No
IPD sharing plan summary	Not provided at time of registration
Publication and dissemination plan	Not provided at time of registration
IPD sharing plan

Study outputs

Output type	Details	Date created	Date added	Peer reviewed?	Patient-facing?
Results article	results	01/02/2011		Yes	No