Israel Medical Association Journal

Background: Vitamin B6 is an essential cofactor in amino acid metabolism. Its deficiency is linked to neuropathy, anemia, and cardiovascular risk. Deficiency is common among hemodialysis patients due to dialytic losses and restrictive diets; however, data related to high-flux (HF) dialysis membranes and Mediterranean dietary patterns are scarce.

Objectives: To assess the prevalence and determinants of deficiency in unsupplemented Israeli hemodialysis patients.

Methods: This retrospective chart review, utilizing a cross-sectional design, was conducted in August 2024. We included 27 chronic hemodialysis patients not receiving vitamin B6 supplementation, representing the available unsupplemented cohort from a unit of approximately 150 patients. Vitamin B6 status was assessed by measuring plasma pyridoxal-5'-phosphate (PLP); deficiency < 20 ng/ml. Clinical and nutritional parameters were evaluated to identify deficiency.

Results: Vitamin B6 deficiency was noted in 63% of patients (median PLP 18 ng/ml, interquartile range 13–23). The cohort was 67% male, median age 74 years. All patients were treated with HF dialyzers. No significant correlations were found between PLP levels and nutritional indices or laboratory markers. A non-significant trend was observed between older age and lower PLP levels (r = -0.35, P = 0.098).

Conclusions: Vitamin B6 deficiency was common among Israeli hemodialysis patients treated with HF dialyzers, despite a presumed Mediterranean diet. It was not associated with nutritional status, suggesting dialysis-related losses, potentially augmented by high-flux membranes, may outweigh intake. Given the high prevalence of deficiency and low cost, routine low-dose vitamin B6 supplementation may be warranted, particularly in older patients.

Background: Patients with type 2 diabetes mellitus (T2DM) have a high rate of cardiovascular disease (CVD). The Mediterranean diet is preferred for CVD prevention. Endothelial dysfunction is demonstrated early in T2DM.

Objectives: To study the effects of dietary intervention of T2DM patients without known CVD on endothelial function and vascular inflammation.

Methods: A prospective study enrolled 22 patients with T2DM. Patients were divided randomly into two groups: an intervention group with 12 patients (55 ± 7 years old, 6 women) and a control group with 10 patients (59 ± 10 years old, 5 women). Clinical evaluation included body mass index (BMI) and endothelial function measured by the flow mediated percent change (FMD%). Fasting blood was drawn on entry to the study and 3 months later, measuring C-reactive protein (CRP), intercellular adhesion molecule-1 (ICAM-1), total cholesterol, triglycerides, and glycosylated hemoglobin (HbA1C%). The intervention was based on weekly telephone calls by a clinical dietitian for 3 months.

Results: In the intervention group CRP and ICAM-1 were reduced (from 4.2 ± 3.3 mg/dl to 0.4 ± 0.5 mg/dl, P = 0.01 and from 258.6 ± 98.3 ng/ml to 171.6 ± 47.7 ng/ml, P = 0.004). Endothelial function (FMD%) was improved (from 0.5 ± 8.0% to 9.5 ± 11.5%, P = 0.014). No change was observed in BMI, HbA1C%, total cholesterol, and triglycerides levels in either group.

Conclusions: Patients with T2DM on the Mediterranean diet who received a weekly telephone call for 3 months improved their endothelial function with reduction of markers of inflammation.