Written by Marcia Egles, MD. Participants who supplemented with flaxseed oil experienced an 8% drop in systolic blood pressure and a 10% drop in diastolic blood pressure.
A recent study from Greece reports flaxseed oil to be of benefit in lowering blood pressure. Flaxseed oil is rich in the omega-3 fatty acid, alpha linolenic acid (ALA). Consumption of omega-3 fatty acids found in fish oils, predominently EPA (eicosapentanoic acid) and DHA (docosahexanoic acid) have been associated with reduced heart disease (1,2). To date there has been relatively little data on the influence of ALA on major heart disease risk factors such as high blood pressure (3).
The study in Greece evaluated the effect of a 12-week dietary supplementation with flaxseed oil on blood pressure in generally healthy men without evidence of health disease. These men had normal or only mildly elevated blood pressures at the start of the study. Eighty-seven male patients, aged 35-70 years, were recruited from the Department of Cardiology at Laiko Hospital in Athens, Greece. They all had high cholesterol levels (for example, total cholesterol over 200 milligrams per decaliter) but they could not be taking cholesterol lowering medications or medications that would lower blood pressure. (The term “dyslipdaemia”,or dyslipidemia, in the title of the study, refers to a non-specific disorder of lipids in the blood. Dyslipidemia patients would generally have high cholesterol and be prone to high blood pressure.) Smokers of more than two packs per day, heavy alcohol users, and those who exercised more than six hours a week were also excluded.
The participants were randomly divided into two groups. One group’s diet was supplemented with 15 ml/day of flaxseed oil. The other group was to take 15 ml of safflower oil per day. Fifteen milliliters of flaxseed oil contains 8 grams of the omega-3 ALA. Safflower oil contains very little ALA and 11 grams of the omega-6, linoleic acid. The regular diets of the two groups were similar Greek diets and were estimated to contain 1 gram per day of ALA, 2200 calories, and to have 36% of their total calories from fat.
The two groups did not differ in their baseline blood pressures averages of 120/80 mm mercury. Blood pressure readings were taken at the start and finish of the study by the same one physician. This physician was unaware of which supplement each participant had received.
At the end of the twelve weeks, the safflower group’s blood pressure was not significantly changed from baseline. The body weights of those in each of the groups were not significantly changed. The flaxseed oil participants had on average a drop in their systolic blood pressure from 120 to 110 mm Hg. Their diastolic blood pressures dropped from 80 to 70 mm Hg. Of these drops in blood pressure, the study’s statistical analysis concluded that a decrease of at least 5mm Hg in both the systolic and diastolic pressures could be attributed to the addition of flaxseed oil to the diet.
A 5mm Hg drop in blood pressure could be considered clinically useful. If this study were done in persons with elevated blood pressures, perhaps even greater lowering might be observed. Fifteen ml of flaxseed oil per day is a substantial amount, but this amount could be easily achieved by incorporating the oil into everyday foods such as salad dressing.
Source: Paschos, G. K., F. Magkos, D. B. Panagiotakos, V. Votteas, and A. Zampelas. “Dietary supplementation with flaxseed oil lowers blood pressure in dyslipidaemic patients.” European journal of clinical nutrition 61, no. 10 (2007): 1201.
© 2007 Nature Publishing Group All rights reserved
Posted July 23, 2008.
References:
- He K, Song Y, Daviglus ML, Liu K, Van Horn L, Dyer AR et al. (2004). Accumulated evidence on fish consumption and coronary heart disease mortality: a meta-analysis of cohort studies. Circulation 109, 2705–2711.
- Holub DJ, Holub BJ (2004). Omega-3 fatty acids from fish oils and cardiovascular disease. Mol Cell Biochem 263, 217–225.
- Wendland E, Farmer A, Glasziou P, Neil A (2006). Effect of alpha linolenic acid on cardiovascular risk markers: a systematic review. Heart 92, 166–169.
