WASHINGTON – The government is telling half of the U.S. population to drastically cut their daily salt intake.

That’s the advice to consumers — and the food industry — as the government issues new dietary guidelines, which are the recommendations behind the popular food pyramid.

For the first time, the Agriculture and Health and Human Services departments, which issue the guidelines every five years, are telling people who are 51 and older, all African-Americans and anyone suffering from hypertension, diabetes or chronic kidney disease to reduce daily sodium intake to little more than half a teaspoon.

That group includes about half of the population and those who are most at risk of having higher blood pressure due to sodium intake. For everyone else, the government continues to recommend about a teaspoon a day — 2,300 milligrams, or about one-third less than the average person usually consumes.

The assault on salt is aimed strongly at the food industry, which is responsible for the majority of sodium most people consume. Most salt intake doesn’t come from the shaker on the table; it’s hidden in foods such as breads, chicken and pasta.

It has long been known that too much sodium increases the risk of high blood pressure, stroke and other problems. But cutting the salt won’t be easy.

The prestigious Institute of Medicine has said it could take years for consumers to get used to the taste of a lower-salt diet. Agriculture Secretary Tom Vilsack said the government is trying to be realistic while targeting the highest-risk groups.

“I think it’s important for us to do this in a way that doesn’t create an immediate backlash,” he said. “If we fail to get our arms around the obesity epidemic, especially in our children, we’re going to see a significant increase in health care costs over time.”

Several large food companies have already introduced initiatives to cut sodium and introduced low-sodium alternatives, but it’s unclear if the industry will be able to cut enough to satisfy the new guidelines. The Food and Drug Administration has said it will pressure companies to take voluntary action before it moves to regulate salt intake.

Dr. Howard Koh, assistant secretary at the Health and Human Services Department, said food companies will have to make cuts for the reductions to work.

“Even the most motivated consumer can make only a certain amount of progress before it’s clear that we need extra support from the food industry,” Koh said.

Consumers still have some control. To reduce the risk of disease from high sodium intake, the guidelines say people should:

_Read nutrition labels closely and buy items labeled low in sodium.

_Use little or no salt when cooking or eating.

_Consume more fresh or home-prepared foods and fewer processed foods, so they know exactly what they are eating.

_Ask that salt not be added to foods at restaurants.

_Gradually reduce sodium intake over time to get used to the taste.

Other recommendations in the guidelines are similar to previous years — limit trans fats, reduce calorie intake from solid fats and added sugars, eat fewer refined grains and more whole grains, consume less than 300 mg per day of cholesterol. The guidelines also recommend eating less than 10 percent of calories from saturated fats — full-fat cheese and fatty meats, for example.

The government promotes these guidelines to consumers by using a symbolic pyramid. Introduced more than five years ago, it doesn’t specify recommended amounts of foods but directs people to a USDA website that details the guidelines. That replaced an old pyramid that specified what to eat after surveys showed that few people followed it.

Vilsack said USDA may come out with a new icon, but that won’t be for a few more months. For now, the government wants consumers to focus on the guidelines themselves.

He says the recommendations — coupled with efforts from industry and other government campaigns for healthy eating, such as first lady Michelle Obama’s “Let’s Move” initiative — should bring about some change in the country’s diet.

“I don’t think it necessarily has to take a generation or two to see some progress,” he said.