Effect of a walnut diet on office and 24-hour ambulatory blood pressure in elderly individuals: Findings from the WAHA randomized trial

But is this just The Hawthorne effect in action? I see nothing here that suggests they took that into account.

Effect of a walnut diet on office and 24-hour ambulatory blood pressure in elderly individuals: Findings from the WAHA randomized trial

Hypertension — Domènech M, et al. | March 19, 2019

Among free-living elders included in a randomized trial assessing the impacts of walnuts at ≈15% energy on age-related disorders (Walnuts and Healthy Aging study), researchers evaluated the 2-year effects on office blood pressure (BP) and 24-hours ambulatory BP of a walnut diet vs a control diet. They included 305 participants in a prespecified analysis and 236 (75%) participants finished the study (65% women; age, 69 years; 60% with mild hypertension). Good tolerability of walnuts was reported, with compliance >98%. Less uptitration of antihypertensive medication was needed in the walnut group vs controls during the trial. Furthermore, the walnut group demonstrated better overall BP regulation vs controls. Elderly subjects who consumed walnuts, especially those with mild hypertension, had a reduction in systolic BP.

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