Reducing sodium intake lowers blood pressure in people with high and borderline high blood pressure. Reducing sodium can also help to prevent the collection of fluid in the lower legs or abdomen. People with Chronic Kidney Disease must control sodium intake to prevent volume overload, which increases blood pressure and causes swelling.

Decreasing sodium can also assist people who have heart failure.

Switching from a higher sodium diet to a lower sodium diet can modestly reduce blood pressure in people who have normal blood pressure. When the sodium intake is lowered from 4000 mg to 2000 mg per day, blood pressure falls by 2 to 3 mmHg. This reduction may be as great as 10 mmHg over several years and can substantially lower the risk of heart disease.

In addition to directly reducing blood pressure, a lower sodium intake may also enhance the effectiveness of high blood pressure medications and other non-drug treatments, such as weight loss. A lower sodium intake has also been associated with other health benefits, including a reduced risk of dying from a stroke, reversal of heart enlargement, and a reduced risk of kidney stones and osteoporosis.