Is there a link between phosphorus intake and blood pressure?
There appears to be no consistent association between total dietary phosphorus intake and blood pressure (BP) in adults in previous studies or in any randomized trial designed to examine this association, a recent systematic review has found.
The investigators included randomized and nonrandomized behavioural intervention and feeding studies (intervention studies), as well as prospective observational studies that measured dietary phosphorus intake or urinary phosphorus excretion and BP. Studies of supplements, children or individuals with major medical conditions were excluded.
PubMed, Embase, Cochrane Trials and clinicaltrials.gov were searched on 1 June 2017 and 22 August 2018. Risk of bias in the assessment of phosphorus exposure and BP was assessed in the studies. A total of 4,759 publications were reviewed, with 14 intervention studies (n=2,497 participants), three prospective observational cohorts (n=17,795) and two ongoing trials included. There were no intervention studies specifically designed to achieve a phosphorus contrast.
In two studies, dietary phosphorus had a significant positive association with systolic BP, while a significant inverse association was found in four studies. On the other hand, eight studies did not find a significant association. In four studies, dietary phosphorus was inversely associated with diastolic BP, while 10 studies found no significant associations.
Furthermore, the risk of incident hypertension was lower comparing the highest with the lowest quintiles of phosphorus intake in two cohorts, whereas one found no significant difference (hazard ratio [HR], 0.86; 0.75–0.98; HR, 0.83; 0.68–1.02; HR, 0.75; 0.45–1.27, respectively).
“Elevated BP is a major cause of preventable disease in the United States and around the world,” the investigators said. “It has been postulated that phosphorus intake may affect BP, with some studies suggesting a direct and others an inverse association.”