Introduction:
The MINISAL survey aimed to assess the age-, gender- and region-specific habitul sodium and potassium intake and its association with relevant anthropometric characteristics in a national sample of Italian healthy children and adolescents referred to centers recognised by the Italian Society of Gastroenterology and Pediatric Nutrition.
Methods:
The study population included 1422 6 to 18 yrs. old subjects from ten regions. Main anthropometric indexes, blood pressure (BP) and 24h urinary sodium and potassium excretion (as proxy for habitual sodium and potassium intake) were measured using carefully standardised procedures.
Potentially incomplete 24h collections were identified and excluded from the analysis based on values of urinary creatinine/Kg body weight and/or a urinary volume below the 5
th
percentile of the overall distribution. The analysis was carried out upon stratification by gender (M=788, F=644), puberal age category: <9 yrs, 9-11 yrs. and 5 months, >11 yrs. and 5 mo. (male); < 8 yrs., 8-10 yrs. and 2 mo., > 10 yrs. and 2 mo. (female), and scholar age category: 6-10 yrs., 11-13 yrs. and 14-18 yrs (both male and female participants).
The relationships among body weight, sodium, potassium and creatinine excretion were analysed using Z-scores as an index of body mass.
Results:
The 24h sodium and potassium excretion were higher in male than in female participants (respectively, 130±63 vs 119±56 mmol; p=0.001 and 39±18 vs 37±16 mmol; p=0.003).
Upon stratification by puberal age and gender, 24h urinary sodium and potassium excretion were respectively 109±54 and 36±19 mol in category 1, 134±60 and 40±16 in category 2 and 152±69 and 43±17 in category 3 for male subjects (p<0.01); 98±39 and 33±13 in category 1, 105±45 and 34±13 in category 2 and 137±63 and 40±18 mmol in category 3 for female individuals (p<0.05).
The expected gender difference in 24h urinary creatinine was observed in all age categories (p<0.05).
Male individuals had consistently greater sodium, potassium and creatinine excretion than female individuals (p between <0.001 and <0.05).
Upon stratification of the study population in four body weight categories (BMI Z-score <0, 0 to <0,9, 1 to <1,9 and ≥2), 24h sodium excretion was significantly greater in obese compared to normal weight children.
24h potassium excretion was also greater in obese children and adolescents compared with their normal weight counterparts (p=0.002).
No significant difference was observed in either sodium or potassium excretion by geographical area.
Conclusions:
The MINISAL survey indicates a substantial age-, gender- and body mass-related variation with average values of sodium intake definitely high when related to true physiological needs or to the “adequate intakes” defined by the health institutions. By contrast, the habitual potassium intake was relatively low and such to indicate an inadequate fruit and vegetable consumption.
Revised Reference Values for Potassium Intake