In 2013 the World Health Organization highlighted that high blood pressure is a global crisis . Hypertension was identified as the number one risk factor attributable to most deaths worldwide and accounted for 16.5% of deaths . Globally, in 2008, 40% of adults aged 25 years or older had hypertension . Many individuals live with undiagnosed, untreated, or uncontrolled hypertension and this can lead to cerebrovascular disease, dementia, stroke, retinopathy, myocardial infarctions, heart failure, coronary artery disease, renal disease, vision impairment, and peripheral arterial disease . Therefore, it is imperative to identify more effective and desirable treatment options to reduce the burden of hypertension globally.
Dietary interventions have been suggested as a preferential complimentary strategy to current pharmacological strategies to control blood pressure . Flaxseed is one dietary intervention that has been used recently to reduce the risk of cardiovascular disease. Flaxseed has exhibited cardioprotective effects in animal models predisposed to cardiovascular disease by reducing atherogenicity [3–5], plasma cholesterol [4, 6], plasma glucose , plasma trans fats , and blood pressure .
In humans, patients with peripheral arterial disease (75% hypertensive) were administered 30 g of milled flaxseed per day for six months . Flaxseed consumption resulted in a large decrease in systolic (-10 mmHg) and diastolic blood pressure (-7 mmHg) that was statistically different from the control group . Blood pressure was inversely associated with plasma concentrations of two flaxseed bioactives, alpha linolenic acid (ALA), and enterolignans .
Despite the significant anti-hypertensive effects demonstrated in the FlaxPAD trial, the results contained some important limitations. Firstly, participants of the FlaxPAD trial were already on anti-hypertensive medication yet still exhibited poorly controlled blood pressure . Therefore it is not possible to conclude if flaxseed can reduce blood pressure as a monotherapy or if it is only effective in conjunction with anti-hypertensive medication. Secondly, it remained unclear if flaxseed could effectively reduce blood pressure in hypertensive patients without coexisting peripheral arterial disease. Therefore, despite evidence showing the potential of flaxseed as a potent cardioprotective functional food, the efficacy of flaxseed as an independent treatment to reduce blood pressure in newly diagnosed patients with primary hypertension has yet to be investigated.
The hypothesis to be tested in the present study is: dietary flaxseed will reduce blood pressure in patients with newly diagnosed hypertension and will reduce the need for anti-hypertensive medication. In order to test these hypotheses, a phase II, randomized, double-blinded, controlled clinical trial called HYPERFlax has been designed. The acronym for the HYPERFlax trial stands for the anti-HYPERtensive effects of dietary Flaxseed. Parameters such as blood pressure, plasma and urine metabolomics, plasma lipid profiling, and plasma vascular tone regulators will be analyzed to assess the efficacy and mechanisms of action of dietary flaxseed in hypertension management.
The aims of the HYPERFlax trial are to:
determine if consuming 30 g of milled flaxseed daily can effectively reduce blood pressure over six months in newly diagnosed stage 1 primary hypertensive participants;
determine if dietary flaxseed is efficacious as a monotherapy;
determine if flaxseed can reduce the need for antihypertensive medication; and
identify the mechanisms of action responsible for the potential anti-hypertensive effects of flaxseed.