Article Text

Download PDFPDF
Flaxseed oil stimulates gynecomastia
  1. Tsuneo Takenaka,
  2. Mayuko Nagano,
  3. Koji Yamashita and
  4. Kiyoshi Kikuchi
  1. Department of Medicine and Surgery, Kokusai Iryo Fukushi Daigaku Daigakuin—Tokyo Aoyama Campus, Minato-ku, Tokyo, Japan
  1. Correspondence to Professor Tsuneo Takenaka; takenaka{at}


Flaxseed oil contains lignans, which exhibit anti-inflammatory and antiatherogenic activities. A 70-year-old male patient presented to our office due to hyperlipidaemia and started to take a tablespoon of flaxseed oil daily. Three months later, he reported left breast swelling and pain. Although the echogram revealed a tumour in the left mammary gland, the breast biopsy was compatible with gynecomastia, showing ductal hyperplasia without evidence of malignancy. His breast epithelia were oestrogen receptor-positive. Potential role of phytoestrogens was discussed.

  • lipid disorders
  • oncology
  • endocrine system

Statistics from


  • Contributors TT performed conduct, reporting, acquisition and interpretation of the data. MN did conduct, conception and design and interpretation of the data. KY performed reporting, conception and design and interpretation of the data. KK performed conduct, conception and design and interpretation of the data.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Patient consent for publication Obtained.

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

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.