Background – There is little recent data on the dietary intake of sodium (Na) and potassium (K) in the Australian population. The best method for assessing dietary Na is 24-hour urine collections, which require a high level of subject co-operation. Dietary assessment can provide an estimate of Na intake but the association between dietary assessment and urinary measurement in Australian community dwelling adults is not known.
Objective – To determine the dietary intake of Na and K measured by 24-hr urinary excretion (UNa and UK) and 24-hr dietary recall (Diet Na and Diet K).
Design – Adults recruited to dietary intervention studies had dietary intake measured using a 24-hr recall (analysed with FoodWorks) and provided a single 24-hr urine collection, whilst on their usual diets.
Outcomes – Of the 144 participants, 85% (54 females (F), 69 males (M)) had UNa over the suggested dietary target (SDT) of 70mmol/day and 62% (32 F, 57 M) were over the upper limit (UL) of 100mmol/day.
Only 19% of participants (5 F, 23 M) met the SDT for K (120mmol/d). Those with two 24hr recalls at baseline (n=88), Diet Na and Diet K were significantly correlated with UNa and UK (r=0.391; B(se)=0.018(0.005); P=0.0001 and r=0.579; B(se)=0.500(0.076); P=0.0001, respectively). BMI was also significantly correlated with UNa (r=0.397; B(se)=5.293(1.318); P =0.0001).
Conclusions – Most participants exceeded the UL for Na and few met the SDT for K. Dietary assessment was correlated with urinary output. Body size was a predictor of UNa and with the increasing BMI of the population, meeting the SDT for Na and K presents a great challenge.