The sodium in salt is responsible for more than 100,000 American deaths a year, about three times more than prostate cancer. Most of the salt Americans consume is hidden away in processed foods, a key reason that most of us take in much more sodium than we need. The major health effect of eating too much salt is a rise in blood pressure, which leads to a heightened risk of heart attack and stroke, reports the October 2010 issue of Harvard Men’s Health Watch.

Although sodium has an important influence on blood pressure, scientists are not sure exactly how it works. It seems likely that eating salt expands blood volume and, in turn, the extra volume may signal the kidneys to trigger a cascade of effects on hormones and blood vessels that raise blood pressure.

Most scientists agree that reducing dietary salt lowers blood pressure, cuts the risk of heart attack and stroke, and saves lives. That’s reason enough to shake the salt habit, but there’s more. Even a modest cutback improves the flexibility of blood vessels and reduces urinary albumin loss, which protects the heart and the kidneys. Salt restriction also lowers the risk of kidney stones by reducing the amount of calcium in the urine.

Current guidelines set an upper limit of 2,300 milligrams (mg) of sodium a day. They go even further—1,500 mg—for people with high blood pressure (hypertension), middle-aged and older adults, and African Americans, who tend to be especially sensitive to the effects of salt. Next month, in part two of the series “Salt and Your Health,” Harvard Men’s Health Watch will help you set your goals for dietary sodium and offer tips for meeting those goals.

Read the full-length article: "Salt and your health, Part I: The sodium connection"