Excess protein intake relative to fiber and cardiovascular events in elderly men with chronic kidney disease

Abstract

Background and aims: The elevated cardiovascular (CVD) risk observed in chronic kidney disease (CKD) may be partially alleviated through diet. While protein intake may link to CVD events in this patient population, dietary fiber has shown cardioprotective associations. Nutrients are not consumed in isolation; we hypothesize that CVD events in CKD may be associated with dietary patterns aligned with an excess of dietary protein relative to fiber.

Methods and results: Prospective cohort study from the Uppsala Longitudinal Study of Adult Men. Included were 390 elderly men aged 70-71 years with CKD and without clinical history of CVD. Protein and fiber intake, as well as its ratio, were calculated from 7-day dietary records. Cardiovascular events were registered prospectively during a median follow-up of 9.1 (inter-quartile range, 4.5-10.7) years. The median dietary intake of protein and fiber was 66.7 (60.7-71.1) and 16.6 (14.5-19.1) g/day respectively and the protein-to-fiber intake ratio was 4.0 (3.5-4.7). Protein-to-fiber intake ratio was directly associated with serum C-reactive protein levels. During follow-up, 164 first-time CVD events occurred (incidence rate 54.5/1000 per year). Protein-fiber intake ratio was an independent risk factor for CVD events [adjusted hazard ratio, HR per standard deviation increase (95% confidence interval, CI) 1.33 (1.08, 1.64)]. Although in opposing directions, dietary protein [1.18 (0.97, 1.44)], dietary fiber alone [0.81 (0.64, 1.02)], were not significantly associated with CVD events.

Conclusions: An excess of dietary protein relative to fiber intake was associated with the incidence of cardiovascular events in a homogeneous population of older men with CKD.

Keywords: CKD; CVD; Fiber intake; Protein intake; Protein–fiber intake ratio.