A Pilot Randomized Crossover Trial Assessing the Safety and Short-Term Effects of Walnut Consumption by Patients with Chronic Kidney Disease

Abstract

The aim of this study of patients with chronic kidney disease (CKD) is to assess the safety of daily consumption of walnuts on the physiological levels of phosphorous, potassium, parathyroid hormone (PTH), and fibroblast growth factor 23 (FGF23), and to assess the short-term benefits of this intervention on risk factors associated with cardiovascular events. This led us to perform a prospective, randomized, crossover, pilot clinical trial examined 13 patients with CKD. Subjects were randomly assigned to a diet of 30 g of walnuts per day or the control diet. After 30 days, each group was given a 30-day washout period, and then switched to the alternate diet for 30 days. Urinary and serum levels of phosphorous and potassium, multiple vascular risk factors, and urinary inositol phosphates (InsPs) were measured at baseline and at the end of the intervention period. Our results showed that the walnut dietary supplement led to reduced blood pressure, LDL cholesterol, and albumin excretion, but had no effect on the physiological levels of phosphorous, potassium, PTH, and FGF23. This is the first report to show that daily consumption of walnuts by patients with CKD does not alter their physiological levels of phosphorous, potassium, PTH, and FGF23 when included in a sodium-, protein-, phosphate-, and potassium-controlled diet, and it could be an effective strategy for reducing cardiovascular risk in patients with CKD.

Walnut Intake Interventions Targeting Biomarkers of Metabolic Syndrome and Inflammation in Middle-Aged and Older Adults: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

“…The results remained statistically significant after performing a leave-one-out sensitivity analysis for each study. The studies that influenced the final result the most were Tapsell et al (2009) [ 36 ] and Abdrabalnabi et al [ 45 ]; their removal brought the I 2 to values lower than or equal to 7%. A subgroup analysis found that studies with a high risk of bias had higher reductions in TG values than studies with some concerns or low risk of bias, the pooled result remaining statistically significant only for high risk of bias studies ( Figure 3 ).…”

Effects of walnut intake on blood pressure: A systematic review and meta‐analysis of randomized controlled trials

“…Another limitation is the follow-up period, which ranged from 4 weeks to 2 years and, therefore, longterm effects (i.e., years) of walnut consumption on BP cannot be estimated. Only two included studies were carried out on a ≥1 year follow-up (Al Abdrabalnabi et al, 2020;Sanchis et al, 2019).…”

“…Finally, 17 articles with 18 comparisons were included in this meta-analysis ( Figure 1). Abdrabalnabi et al, 2020;Katz et al, 2012;Ma et al, 2010;Njike, Ayettey, Petraro, Treu, & Katz, 2015;Rock, Flatt, Barkai, Pakiz, & Heath, 2017;Spaccarotella et al, 2008;Tindall et al, 2019), Republic of Korea (Hwang et al, 2019), Australia (Ndanuko, Tapsell, Charlton, Neale, & Batterham, 2018), Iran (Fatahi, Haghighatdoost, Larijani, & Azadbakht, 2019;Nezhad, Aghasadeghi, Hakimi, Yarmohammadi, & Nikaein, 2016), United Kingdom (Din et al, 2011), Spain (Olmedilla-Alonso et al, 2008;Ros et al, 2004;Sanchis et al, 2019), Chine (Wu et al, 2010), and New Zealand (Mukuddem-Petersen, Stonehouse Oosthuizen, Jerling, Hanekom, & White, 2007). The follow-up period ranged from 4 weeks to 2 years.…”

Walnut consumption and health outcomes with public health relevance—a systematic review of cohort studies and randomized controlled trials published from 2017 to present

“…Eight of the RCTs were parallel group studies, 63 , 64 , 78 , 79 , 82–89 , 92–94 and 5 employed a crossover design. 65 , 80 , 81 , 90 , 91 , 95–97 RCTs were conducted in Australia, Cyprus, Germany, Iran, South Korea, Spain, Tunisia, Turkey, and the United States. The number of enrolled subjects ranged from 15 to 708, and study duration ranged from 3 weeks to 2 years.…”