Flax Seed Lowers Blood Pressure

Article by Ann Walker, Photo by byuppi

Flax seeds have long been used as a medicine to counter constipation. However, the use of the herb for respiratory and urinary tract problems as mentioned in Mrs Grieve’s 1932 book - a Modern Herbal (a book which summed up the then know Materia Medica of the western herbal medicine tradition) - has largely died out. However, modern research has revealed hitherto unknown properties of the herb, mostly due to high levels of the herb’s unusual compound called ‘SDG’ (secoisolariciresinol diglucoside), which is a lignan with plant- or phyto-oestrogenic and antioxidant properties.

These properties can help to normalise hormonal imbalance in women’s health problems associated with too much or too little oestrogen (e.g. premenstrual syndrome and menopause). SDG also shown promising cardiovascular-protective and anti-cancer properties. The latter only in laboratory animal studies, but the former in clinical trials, including those focusing on blood-pressure lowering.

In 2016 a collaborative group of scientists from Australia, Poland and Romania undertook a meta-analysis of human studies on flaxseed supplements for high blood pressure (PMID: 26071633). They searched the world’s medical literature and found 15 clinical trials with a total of 1302 volunteers to include in the analysis.

Pooling all the results showed significant reductions in both systolic and diastolic blood pressure following supplementation with whole flaxseed powder rather than the oil or the purified SDG. There was a greater effect on both these values in trials of more than 12 weeks. Flaxseed is turning out to be a lot more versatile than we thought!

PMID = PubMed identifier

Ann Walker PhD, FCPP, MNIMH, RNutr
Course Director DHM
Herbal Practitioner