The new study, published in theJournal of Clinical Endocrinology & Metabolim, investigated the relationship between dietary sodium intake and incidence of diabetes complications, after researchers noted that while many guidelines recommend people with type 2 diabetes should reduce dietary sodium intake, the relationship between salt intake and the incidence of diabetic complications in type 2 diabetics "has not been explored."
Led by Chika Horikawa from the University of Niigata Prefecture in Japan, the team from more than 1,500 people who had taken part in a nationwide cohort study of people with type 2 diabetes - finding that high dietary sodium intake is associated with elevated incidence of cardiovascular disease (CVD) in patients with type 2 diabetes, "and that there is a synergistic effect between HbA1c [glycated hemoglobin] values and dietary sodium intake for the development of CVD."
"The study's findings provide clear scientific evidence supporting low-sodium diets to reduce the rate of heart disease among people with diabetes," said Horikawa.
"Although many guidelines recommend people with diabetes reduce their salt intake to lower the risk of complications, this study is among the first large longitudinal studies to demonstrate the benefits of a low-sodium diet in this population."
The nationwide cohort study surveyed participants in the Japan Diabetes Complications Study who were between the ages of 40 and 70 and had been diagnosed with diabetes. In all, 1,588 people responded to a survey about their diets, including sodium intake.
The researchers reviewed data on cardiovascular complications participants experienced over the course of eight years and used data from the dietary recall survey to analyse the any potential associations.
The team divided the participants into four groups based on their sodium intake. The analysis found people who ate an average of 5.9 grams of sodium daily had double the risk of developing cardiovascular disease than those who ate, on average, 2.8 grams of sodium daily, while the effects of a high-sodium diet were exacerbated by poor blood sugar control.
"To reduce the risk of developing cardiovascular disease, it is important for people who have type 2 diabetes to improve their blood sugar control as well as watch their diet," Horikawa said.
"Our findings demonstrate that restricting salt in the diet could help prevent dangerous complications from diabetes."
Source: The Journal of Clinical Endocrinology & Metabolism
Published online ahead of print, doi: 10.1210/jc.2013-4315
"Dietary Sodium Intake and Incidence of Diabetes Complications in Japanese Patients with Type 2 Diabetes – Analysis of the Japan Diabetes Complications Study (JDCS)"
Authors: Chika Horiakwa, Yukio Yoshimura, et al