Further analysis of data from a 2011 study on the effect of the 'portfolio diet' on cholesterol has found that it also lowered blood pressure by an average 2% more than the DASH diet, a diet specifically designed to reduce hypertension, which is associated with a 5-10 mm blood pressure improvement.
The Canadian study involved 241 participants with hyperlipidemia, of whom 82 were randomly assigned to a DASH-type diet (control group) and 159 to the portfolio diet. Compared to the control, the portfolio diet reduced systolic, diastolic and mean arterial blood pressure by 2.1 mm Hg, 1.8 mm Hg and 1.9 mm Hg, respectively. Blood pressure reductions were small at 12 weeks and only reached significance at 24 weeks.
The portfolio diet includes foods that have been shown to lower cholesterol including mixed nuts, soy protein, plant sterols (found in vegetable oils and leafy vegetables) and viscous or soluble fiber. Viscous fiber is found only in plant-based food; rich sources include asparagus, Brussels sprouts, sweet potatoes, turnips, apricots, mangoes, oranges, legumes and oat bran.
However, the DASH diet did have higher compliance rates.
Jenkins, D.J.A. et al. 2015. The effect of a dietary portfolio compared to a DASH-type diet on blood pressure. Nutrition, Metabolism and Cardiovascular Diseases, 25 (12), 1132-1139. http://dx.doi.org/10.1016/j.numecd.2015.08.006