Americans need to lower salt intake, but lowering dietary sodium too much may also be harmful, according to a new report.

An expert committee convened by the Institute of Medicine (IOM) reviewed current research on the relationship between dietary sodium, heart disease, and health, including studies that have associated excess dietary sodium with heart attack and stroke.

"This is a two-sided message: We endorse public health efforts to lower excessive salt intake, but we raise questions about harm from too little salt," said Brian Strom, IOM's committee chairman and executive vice dean of the Perelman School of Medicine at the University of Pennsylvania.

American adults consume on average 3,400 mg of sodium (1.5 teaspoons) each day, mostly from processed foods and restaurants. 97 percent of children and adolescents eat too much salt, according to the American Heart Association (AHA).

The government recommends less than 2,300 mg sodium for adults. For adults 51 and older, African Americans, and people with hypertension, diabetes, and chronic kidney failure, the government recommends reducing sodium intake to 1,500 mg each day.

The American Heart Association recommends 1,500 mg sodium or less each day.

Among the IOM report's findings was that studies were "inconsistent and insufficient" and could not accurately say whether reducing daily sodium intake to 2,300 mg increases or decreases risk of heart disease, stroke, and death. Additionally, low sodium may be bad for those with mid- to late-stage heart failure, the report said. The report also claimed that evidence does not support the 1,500 mg or less recommendation for people over 51, African Americans of any age, or people with hypertension, diabetes, or chronic kidney failure.

The IOM committee did not define "excessive" sodium nor did it recommend a limit. In a few years, another committee will make those recommendations, said Strom.

Maintaining a diet that contains only 1,500 mg sodium is "extremely hard," he added.

The Center for Science in the Public Interest (CSPI) agrees that low-sodium diets are difficult to maintain. Restaurants serve up nearly 2,000 mg of sodium in just one burrito, a single-serving pizza, or an order of kung pao chicken, and a typical sandwich or burger yields at least 1,000 mg, the organization said in a statement, following the IOM report.

Getting down to 2,300 will be nearly impossible until the government phases in reasonable limits on the sodium content of foods, according to a CSPI study published Monday in JAMA Internal Medicine.

Although the IOM study cautioned against excessive sodium, it also emphaszed that low sodium levels could present health risks of their own.

"When you look at subgroups, there are suggestions that as you go to lower dietary sodium, the health risks begin to increase, but there are methodological limitations to that research," said Strom.

Elliott Antman, a spokesman for the American Heart Association and a professor of medicine at Harvard Medical School, said the studies that were reviewed by the IOM committee were flawed. Some of them conducted research using sick patients, and were not designed to study the effects of dietary sodium on cardiovascular health.

The AHA reviewed many of the same studies as the IOM and found their usefulness for public health recommendations limited by substantial methodological concerns, according to Antman.

The AHA stuck to their recommended sodium limit of 1,500 mg or less per day, claiming it is "based on the strength of evidence relating excess sodium intake to high blood pressure, cardiovascular disease and stroke," Antman said. "We have evidence that reduced intake of sodium can prevent and treat hypertension and reduce the risk of adverse cardiovascular disease and stroke events."

For some, sodium holds excess fluids in the body, increasing blood pressure and placing added burden on the heart, the AHA said.

"[The AHA] is not going to change its position on sodium, and it stands with many other major health organizations," Antman said. "We don't want people to be distracted from the important health message that there is benefit in aggressively lowering sodium from the current levels in the American diet."

A spokesman for the salt industry took a different viewpoint.

Morton Satin, vice president of science and research for the Salt Institute, said, "The report challenges the radical viewpoint of cutting sodium to 1,500 milligrams or below a day. This low amount has been shown to increase the health risks for some people."

"The report's recognition that more research is needed marks a positive approach toward a more objective discussion about the complex effects of sodium reduction on overall health," he added.

Bonnie Liebman, CSPI Nutrition Director, emphasized the need to reduce sodium intake. "What the committee failed to emphasize is that most Americans are deep in the red zone, consuming 3,500 to 4,000 milligrams of sodium a day," Liebman said in a statement.

"It's clear that those excessive levels increase the risk of high blood pressure, heart attacks, and strokes," Liebman said. "Whether we aim for 2,300 or 1,500 milligrams a day is irrelevant until we move down out of the red zone."

To reduce your sodium intake, the AHA offers the following tips at its website:

  • Read the Nutrition Facts label to compare and find foods lower in sodium.
  • Choose fresh fruits and vegetables, when possible.
  • Limit the amount of processed foods you eat and your portion size.
  • Avoid adding salt when cooking and/or eating.
  • Learn to use spices and herbs to enhance the taste of your food. Most spices naturally contain very small amounts of sodium, but read the label to be sure.
  • Add fresh lemon juice instead of salt to fish and vegetables.
  • Specify how you want your food prepared when dining out. Ask for your dish to be prepared without salt.
  • Take control of what's in your food by cooking more at home.
  • Choose foods with potassium. They counter the effects of sodium and may help lower your blood pressure.