Gastrorenal Axis

H ypertension is present in 40% of the world's popula- tion and is responsible for 12.8% of total deaths. 1 In the United States, hypertension affects 32% (2011-2012) of the middle-age (40-59 years) adult population and is responsible for 35.6% of total deaths. 2-4 However, these statistics do not include normotensive individuals who are salt sensitive. Almost half of the US population has hypertension, salt sensitivity, or both. 5 Salt sensitivity, independent of the presence of hypertension, is a risk factor for not only cardiovascular morbidity and mortality Salt sensitivity may also interfere with the normal circadian rhythm of blood pressure. 9 Failure of the normal night-time dip in blood pressure may be associated with an increase in cardiovascular morbidity and mortality. he World Health Organization recommends reducing salt consumption to <5 g of NaCl per day in adults, to help prevent hypertension, heart disease, and stroke. 11 In a recent metaanalysis of randomized controlled trials, it was concluded that in the normotensive population, there is no relationship between the amount of sodium restriction (136-188 mmol/d) and blood pressure level. However, in the prehypertensive and hypertensive populations, reduction in sodium intake (77-140 mmol/d) correlated with a decrease in blood pressure. nother meta-analysis indicated that a modest reduction in salt intake for 4 weeks causes a decrease in blood pressure levels in both hypertensive and normotensive individuals. In subjects with no history of hypertension, no association was found between dietary sodium or potassium intake with hypertension or prehypertension. 14 However, a lower limit of the daily NaCl intake is not defined. This is important because the relationship between sodium intake and blood pressure may not be linear but more of a J-shaped curve. There is evidence for an increase in cardiovascular risk at low levels of sodium ingestion. 9]