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Original research
Determining the mechanisms of dietary turnip rapeseed oil on cholesterol metabolism in men with metabolic syndrome
  1. Harri Juhani Saarinen1,
  2. Chaiyasit Sittiwet2,3,
  3. Piia Simonen4,
  4. Markku J Nissinen2,
  5. Ulf-Håkan Stenman5,
  6. Helena Gylling6,
  7. Ari Palomäki7,8,9
  1. 1 Department of Cardiology, Kanta–Häme Central Hospital, Hameenlinna, Finland
  2. 2 University of Helsinki and Helsinki University Central Hospital, Abdominal Center, Helsinki, Finland
  3. 3 Mahasarakham University, Mahasarakham, Thailand
  4. 4 University of Helsinki and Helsinki University Central Hospital, Heart and Lung Center, Helsinki, Finland
  5. 5 University of Helsinki and Helsinki University Central Hospital, Clinical Chemistry, Helsinki, Finland
  6. 6 University of Helsinki and Helsinki University Central Hospital, Internal Medicine, Helsinki, Finland
  7. 7 Department of Emergency Medicine, Kanta–Häme Central Hospital, Hameenlinna, Finland
  8. 8 Linnan Klinikka, Cardiometabolic Unit, Hameenlinna, Finland
  9. 9 University of Tampere, Tampere, Finland
  1. Correspondence to Dr Harri Juhani Saarinen, Department of Cardiology, Kanta–Häme Central Hospital, Ahvenistontie 20, FI-13530 Hämeenlinna, Finland; harri.saarinen{at}


We have earlier reported the reduction of total cholesterol, low-density lipoprotein (LDL) cholesterol and oxidized LDL caused by short-term modification of diet with cold-pressed turnip rapeseed oil (CPTRO) instead of butter. The aim of this supplementary study was to determine whether the beneficial effects resulted from altered cholesterol metabolism during the intervention.

Thirty-seven men with metabolic syndrome (MetS) completed an open, randomized and balanced crossover study. Subjects’ usual diet was supplemented with either 37.5 g of butter or 35 mL of CPTRO for 6–8 weeks. Otherwise normal dietary habits and physical activity were maintained without major variations. Serum non-cholesterol sterols were assayed with gas–liquid chromatography and used as surrogate markers of whole-body cholesterol synthesis and absorption efficiency. Serum proprotein convertase subtilisin/kexin type 9 (PCSK9) concentration was analyzed with Quantikine ELISA Immunoassay. Serum cholesterol synthesis markers and serum cholestanol (absorption marker), all as ratios to cholesterol, did not differ between the periods. Serum campesterol and sitosterol ratios to cholesterol were significantly increased after the administration of CPTRO resulting from the increased intake of 217 mg/day of plant sterols in CPTRO. Serum PCSK9 concentration did not differ between CPTRO and butter periods.

The reduction in serum cholesterol by 7.2% after consumption of rapeseed oil could not be explained by changes in cholesterol absorption, synthesis or PCSK9 metabolism in MetS. NCT01119690.

  • Cholesterol
  • Polyunsaturated Fatty Acids
  • Fatty Acids, Monounsaturated
  • Atherosclerosis
  • Dietary Fats

This is an Open Access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See:

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  • Contributors AP and HG designed this study. HJS, CS, PS, MJN, UHS, HG and AP participated in the acquisition of data and analysis of data. HJS, HG and AP participated in drafting the manuscript. CS, PS, MJN, and UHS critically revised the manuscript. All authors read and approved the final manuscript.

  • Funding This study was supported by grants from the Ministry of Health and Social Welfare in Finland through the Medical Research Fund of Kanta-Häme Central Hospital, the Häme Regional Fund under the auspices of the Finnish Cultural Foundation, Kankaisten Öljykasvit Ltd, and Hilkka and Väinö Kiltti Foundation. None of them had a role in data collection, analysis of the results or preparation of the manuscript.

  • Competing interests None declared.

  • Patient consent Obtained.

  • Ethics approval The Ethics Committee of the Kanta-Häme Hospital District.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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