Australian diabetics fail to meet national dietary sodium, potassium guidelines

20 August 2010

MedWire News: Few Australian patients with Type 2 diabetes meet Australian National Health Foundation (NHF) guidelines for daily sodium or potassium intake, researchers report.

These guidelines recommend a daily sodium and potassium intake of less than 100 mmol and more than 120 mmol, respectively, for individuals with a high risk for cardiovascular (CV) disease.

However Elif Ekinci (Austin Health, Victoria, Australia) and team found that “only 3% of male patients and 14% of female patients with Type 2 diabetes met the Australian NHF guidelines for sodium consumption.”

The researchers assessed the 24-hour urinary sodium (uNa), potassium (uK), creatinine (uCr), urea (uUrea), and glucose (uGlc) levels of 122 Australians with Type 2 diabetes, over a mean of 5 years, collecting a mean 1.9 samples per patient per year.

At baseline, all patients received dietary advice stressing actions such as avoiding high-energy processed foods and consuming lots of fresh fruit and vegetables.

By the end of the study, the mean patient uNa level was higher than the NHF recommendation, at 170 and 142 mmol/day in men and women, respectively. Mean uK level, however, was lower than the NHF recommendation, at 75 and 62 mmol/day in men and women, respectively.

After adjustment for insensible sodium and potassium losses, a significantly smaller proportion of men met the NHF sodium guidelines than women, at 3% versus 14%. However, significantly fewer women than men met NHF potassium guidelines, at 3% versus 14%.

Of note, body mass index (BMI), uUrea level, urine volume, and uGlu level were all independent predictors of uNa level.

“The strong association of urinary sodium with BMI is likely to reflect excessive consumption of sodium-rich processed food,” the researchers hypothesize in the journal Diabetic Medicine.

They say that hypertensive and normotensive individuals could reduce their systolic blood pressure (SBP) by 5 and 2.5 mmHg, respectively, simply by reducing their salt intake by 3g per day.

This reduction in SBP “would be expected to produce a CV benefit in the general population equating to an approximate 13% reduction in stroke and 10% reduction in ischemic heart disease,” they conclude.

Ekinci et al add, however, that “it remains to be shown whether salt restriction can be maintained outside study conditions and whether it can reduce CV outcomes in diabetes.”

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Diabet Med 2010; Advance online publication