Linaceae Flax; flaxseed oil Lini semen; Lini oleum virginale Seeds, expressed fixed oil The seed contains a fixed oil, the main constituents of which are glycerides of linoleic and linolenic acid and mucilage composed of a rhamnogalacturonan backbone. It also contains the lignans secoisolariciresinol and its diglucoside (SDG), the cyanogenetic glycosides linamarin, lotaustralin, linustatin and neolinustatin, proteins, minerals and vitamins (EMEA 2006b; Kaewmanee et al. 2014; Williamson et al. 2013). Even though the evidence based on controlled clinical studies is somewhat limited, for some of the key indications, especially for the management of gastrointestinal discomfort, use of linseed is well established based on medical experience. In other cases, the evidence is much more limited. In a randomised investigator-blinded trial, patients (55 subjects) received either linseed (roughly ground, partly defatted) or psyllium seed 6–24 g a day for 3 months for the treatment of constipation with irritable bowel syndrome. Linseed treatment showed a significant decrease in constipation and abdominal symptoms (bloating and pain) compared to psyllium. After the blinding period, 40 out of 55 patients continued in an open period of further 3 months with only flaxseed treatment and constipation and abdominal symptoms were further reduced. (Tarpila et al. 2003). A meta-analysis on the effects of flaxseed and flaxseed-derived products (flaxseed oil or lignans) on blood lipids, which included 28 randomised clinical trials (1539 subjects) concluded that the consumption of flaxseed and its derivatives reduced blood total and LDL-cholesterol concentrations, with no effect on HDL-cholesterol levels and triglycerides. The effect was more evident when whole flaxseed was used in (particularly postmenopausal) women and in subjects with initial higher cholesterol levels (Pan et al. 2009). In children, however, the use of flaxseed for hypercholesterolemia might not be a viable option. A study of paediatric patients (given flaxseed in muffins and bread) found that it was associated with adverse changes in the lipid profile of these children, although a potential benefit of low-density lipoprotein cholesterol lowering could not be excluded (Wong et al. 2013). Although no other safety concerns have been noted, further evidence is needed to support its use for the prevention of hypercholesterolaemia.
Linseed (Flaxseed)
Linum usitatissimum L.
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Gastrointestinal discomfort including constipation and irritable bowel syndrome:
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