The recently released 2020-2025 Dietary Guidelines from the Agriculture Department remind Americans that they should consume less than 2,300 milligrams of salt a day — equivalent to about a teaspoon. Instead, we eat nearly 50 percent more than that, according to the Centers for Disease Control and Prevention.

The recommendation is the same as in the earlier 2015-2020 guidelines, yet the average American has not cut down on salt, still consuming an average of more than 3,400 mg daily, according to the CDC.

Even though the vast majority of public health experts regard too much salt as a killer and urge you to do whatever you can to cut back, Americans find that difficult. One reason is that more than 70 percent of salt in the American diet comes from packaged and prepared foods, according to the Food and Drug Administration, not from the salt shaker at home.

“We are awash in foods that are high in sodium,” says Thomas Frieden, former director of the CDC. “Sodium reduction is one of the most neglected and under-implemented public health interventions. Yet, there is absolutely no doubt that excess sodium is resulting in deaths.”

The villain in salt (also known as sodium chloride) is sodium, which makes up about 40 percent of salt.

Excess sodium narrows and stiffens blood vessels, raising blood pressure, which can lead to heart disease, stroke and other serious medical conditions. The World Health Organization (WHO) estimates that 2.5 million deaths annually could be prevented if global sodium consumption were reduced to recommended levels.

Countless health bodies — the American Heart Association, the American College of Cardiology, the CDC, the National Academies of Sciences, Engineering and Medicine, and WHO, among others — and numerous public health experts recommend that consumers dramatically reduce their sodium intake. That position is based on decades of scientific evidence (including analyses of hundreds of published studies that underscore sodium’s health dangers) that remains unchanged despite several studies in recent years that have challenged it.

“Every respected and authoritative organization keeps reinforcing that message, and it is a very consistent message,” says Penny Kris-Etherton, distinguished professor of nutrition at Pennsylvania State University’s College of Health and Human Development. “Salt raises blood pressure. Blood pressure is a major risk factor for cardiovascular disease. If we decrease salt, we can decrease blood pressure and decrease cardiovascular disease. It’s as simple as that.”

Several years ago, controversy arose after several studies suggested that the amount of sodium that most people consume — which public health officials say is too much — won’t hurt them; rather, heart disease risk rose among those who ate more than what most Americans now consume, and also increased among those who ate very little, well below what people typically eat now.

One set of studies, for example, from a project known as the Prospective Urban Rural Epidemiology (PURE), concluded that between 3,000 and 5,000 mg of sodium per day was associated with a lower risk of death and fewer heart attacks compared with a much higher or much lower intake. Numerous public health experts condemned the research as both flawed and dangerous.

“Really, the science at this point is settled and there is no doubt,” Frieden says. “It’s surprising and disappointing that these scientists have ignored definitive evidence that their studies are wrong.”

They faulted the researchers for calculating total daily sodium intake based on a single morning urine sample, rather than multiple samples taken over 24 hours, and for using a formula that includes heart disease risk factors such as age and body mass index, thus creating potentially biased results. Critics also say the work did not exclude participants with preexisting health problems, including those that could make them vulnerable to heart disease.

“The methodology is so unsound that it was surprising to me that it got published,” says Graham MacGregor, professor of cardiovascular medicine at the Wolfson Institute at Queen Mary University of London.

But Andrew Mente, associate professor in the Population Health Research Institute at McMaster University in Ontario — one of the co-authors of the controversial studies — dismisses the criticism.

“People always disagree with work that challenges their beliefs,” he says. “New data is always questioned by people who are longtime proponents of old dogma.”

Mente says both the methodology and results were sound and have been confirmed by other research, including studies where urine samples were taken over 24 hours.

He says that their research does not propose consumers eat unlimited amounts of sodium, but instead opt for intake somewhere between 3,000 and 5,000 mg, higher than what public health officials recommend. “What we’re eating right now is about what we should be eating,” he says.

Most people have a tough time cutting back to the amount of salt that health experts recommend. “The major reason it’s hard to reduce sodium is because it’s hard to reduce sodium,” Frieden says.

That’s because food manufacturers add salt to a vast array of their products, including bread, soups, processed meats, and even in the unexpected, such as fresh meat, poultry, and fish and breakfast cereal.

“It’s unrealistic to ask millions of Americans to worry about long-term concerns, when there are immediate ones, such as a pandemic,” says Michael Jacobson, co-founder and senior scientist with the Center for Science in the Public Interest — and author of a new book “Salt Wars.” “The whole food environment is loaded with sodium. It’s impossible.”

Moreover, even when consumers pay attention to food labels — which provide sodium content — it’s difficult. Sodium is listed by serving amount, which can be difficult when serving sizes are small.

“A normal serving of soup is a cup, and if you eat a bowl, you could be getting four cups,” says Andrew Freeman, who co-chairs the Nutrition and Lifestyle Workgroup for the American College of Cardiology. “Consumers need to understand that serving size is a multiplier of the amount of salt they may be getting.”

Jacobson suggests that consumers shun processed foods if they can, and prepare meals from scratch, using “lite” salt, which contains 50 percent less sodium. Read labels, and compare different brands of the same or similar product to find the one with the least amount of sodium, he advises. And eat out less often, perhaps easier now with many pandemic-related bans on indoor restaurant dining. If you do go to a restaurant, however, “split large entrees into two meals when possible,” he says.

Most experts believe that the best way to achieve lower sodium consumption is for the packaged food and restaurant industries themselves to decrease sodium in their products before the food reaches consumers.

In 2010, the Institute of Medicine called upon the FDA to regulate the amount of sodium permitted in processed foods, saying the agency should require manufacturers to gradually reduce sodium levels over time to allow Americans’ taste buds to adjust. In 2016, the FDA proposed voluntary guidelines, but they were never finalized.

“The challenge for the FDA under the Biden administration will be to finalize the guidelines and pressure industry to enact them,” Jacobson says.

Such a plan worked in the United Kingdom, where the food industry voluntarily dropped sodium levels in many food products over 15 years by between 20 to 50 percent, MacGregor says.

“Blood pressure fell and death rates fell,” he says. “About 20,000 strokes and heart attacks a year were prevented, of which an estimated 10,000 would have been fatal. Such a simple thing, but it was amazing. It just tells you that you can do it. Salt taste receptors adjust to reduced salt intake. The public doesn’t even know it, but we’ve got them eating less salt.”

Many public health experts like the idea of resetting the palate.

“When you are used to eating large quantities of salt, your salt thermostat adjusts upward, so people don’t realize when they are consuming large quantities,” Freeman says. “It doesn’t taste salty. After a couple of weeks without any added salt, you will notice how salty your food has been.”

Frieden agrees. “Your set-point for sodium is not innate,” he says. “If you steadily reduce your sodium and then later — if you could time travel back to your current food — it would taste inedible.”