Eating too much salt can cause or exacerbate hypertension because studies have shown that the prevalence of hypertension is positively correlated with the average amount of salt consumed and that excessive salt intake can lead to increased blood pressure, mainly in those who are more sensitive to salt. Eating too much salt can sometimes cause sodium retention, which can lead to increased blood pressure, but the mechanism by which it causes the increase is not known. Sodium retention occurs infrequently, but it may occur in conditions such as changes in renal blood flow, renal units, angiotensin or adrenal steroids, and consequent changes in urinary sodium excretion pressure in the kidneys, which may be lowered by a salt-restricted diet in patients with hypertension.