Low glycaemic diet may lower blood pressure
A lower glycaemic diet is associated with significant reductions in blood pressure, according to the results of a systematic review and meta-analysis. However, many of the randomized controlled trials (RCTs) included report important sources of bias.
Researchers searched databases in two phases. Medline, Embase, CAB Abstracts, Biosis, ISI Web of Science and the Cochrane Library were searched from January 1990 to December 2009. An updated search was performed using Medline and Embase from January 2010 to September 2016.
RCTs included reported author-defined high- and low-glycaemic index (GI) or glycaemic load (GL) diets and blood pressure, had ≥6 week duration, and comprised healthy participants without chronic conditions. Stata statistical software was used to extract and analyse data.
A total of 14 trials comprising 1,097 participants met the eligibility criteria.
There were 13 trials that provided information on differences in GI between control and intervention arms. A median decrease of 10 units in GI reduced the overall pooled estimates for systolic blood pressure (SBP) by 1.1 mm Hg (95 percent CI, ‒0.3 to 2.5 mm Hg; p=0.11) and for diastolic blood pressure (DBP) by 1.3 mm Hg (0.2 to 2.3 mm Hg; p=0.02).
A total of nine trials reported information on differences in GL between arms. A median decrease of 28 units in GL reduced the overall pooled estimates for SBP by 2.0 mm Hg (0.2 to 3.8 mm Hg; p=0.03) and for DBP by 1.4 mm Hg (0.1 to 2.6 mm Hg; p=0.03).
“High blood pressure is a strong risk factor for cardiovascular disease,” researchers said.