ESTIMATION OF DAILY SALT INTAKE OF HEALTHY AMBULANT NIGERIAN ADULTS

ABSTRACT

Data on the current levels of sodium consumption of Nigerian adults are urgently needed to determine the contribution of dietary sodium as a risk factor in the increasing incidence of hypertension and related complications in the country. The aim of this study was  to  estimate  the daily salt  intake of healthy ambulant Nigerian adults  using  the  24-hour  urinary  sodium ion excretion method (the gold standard) and spot urine sodium ion excretion method (a proposed convenient alternative). Eighty  adult  Nigerians  aged  between  20  and  50 years  made  up  of 60% males and 40% females were the subjects that provided 24-hour urine and spot urine samples. Urinary sodium excretion was estimated using the atomic absorption spectrophotometer (AAS). Measured 24-hour urinary sodium excretions for male and female subjects were 4.7+0.5 and 4.0+0.6 g/day respectively. This translates to a dietary salt intake of 11.8+1.3 g/day for male subjects and 10.1+1.5 g/day for female subjects. A significant decrease (p<0.01) was observed between the values obtained by 24-hour urinary sodium excretion method and spot urinary sodium excretion method. Estimated 24-hour urinary sodium ion excretion positively correlated (r=+61) with spot urinary sodium excretion. Age dependent increase was observed in both measured and estimated 24-hour urinary sodium ion excretion. Systolic and diastolic blood pressure increased significantly (p<0.05) with increase in measured 24-hour urinary sodium ion excretion. Based on these results, the salt intake of all the subjects as determined by both methods far exceeded the recommended daily salt limit of < 5.0g/day. The positive correlatrion (r= +0.61) between the results obtained from both methods suggests that notwithstanding the differences between the values obtained, the spot urinary excretion method can be used to determine the daily dietary salt intake of Nigerians.