posted on 07/17/2022 06:00
Flat spoon of tea has the maximum amount of salt that should be ingested daily – (Credit: Sukhjinder/PixaHive/Disclosure)
The expression “without salt” refers to something bland and bland. But, if it is true that this nutrient makes food tastier, in excess it can cause serious health problems. While sodium chloride’s association with cardiovascular disease is well established, there is also scientific evidence of its association with cancer, osteoporosis, and chronic kidney disease. Recently, a study with data from more than 501,000 people showed a statistical relationship between a higher amount of the nutrient at the table with the risk of premature death (before age 75) from any cause.
The research was published in the European Heart Journal and conducted by the School of Public Health and Tropical Medicine at Tulane University in the United States. The data showed that, compared to people who never or rarely added salt to their food — previously seasoned in preparation — those who added an extra portion had a 28% higher risk of dying prematurely. Professor Lu Qi, lead author, warns that, in population terms, the habit can kill one in 100 people between the ages of 40 and 69.
“To the best of my knowledge, this is the first study to assess the association between the addition of salt to foods and premature death,” says Qi. “The results provide new evidence to support recommendations on modifying eating behaviors to improve health. Even a modest reduction in sodium intake, adding less or no salt to foods at the table, is likely to result in substantial health benefits,” he notes. .
The data, collected from a large British population study, included information from 501,379 people. When entering the research, between 2006 and 2010, they were asked about the frequency of adding salt to already seasoned food: never/rarely, sometimes or always. To determine the nutrient-specific influence on the risk of early death, the researchers adjusted the analysis, taking into account factors such as age, sex, body mass index, smoking, alcohol intake, physical activity level, dietary habits, and comorbidities such as diabetes, cancer and cardiovascular disease. The volunteers were followed, on average, for nine years.
In addition to finding that adding salt to foods was associated with a higher risk of premature death from all causes and a reduction in life expectancy (1.5 years for men and 2.28 years for women), the researchers concluded that it tended to be slightly reduced in people who consumed the highest amounts of fruits and vegetables. “We were not surprised by this finding, as fruits and vegetables are the main sources of potassium, which has protective effects and is associated with a lower risk of premature death,” says Qi.
According to the researcher, assessing overall sodium intake is very difficult, as many foods, especially pre-prepared and processed foods, have high levels of the element added before they reach the table. Studies investigating salt intake through urinalysis often only consider a sample and, according to Qi, “do not necessarily reflect usual behavior.”
So the scientists chose to see whether or not people added salt to food, regardless of whether the seasoning was added during cooking. “In the Western diet, the addition of table salt accounts for 6% to 20% of total sodium intake and provides a unique way to assess the association between habitual sodium intake and risk of death. But as our study is the first to report a relationship between the addition of salt to foods and mortality, more analysis is needed to validate the findings before making recommendations,” he acknowledges.
The study is observational, that is, it does not make a relationship between cause and effect. However, several studies have found an association between excess salt and health risks. One, published in the Archives of Internal Medicine, found that people on high-sodium, low-potassium diets were 20% more likely to die from any cause. In addition, those with the highest ratio of sodium to potassium in their diet are twice as likely to die from a heart attack. “Sodium and potassium are closely related, but they have opposite effects on the body,” explains the study’s corresponding author, Quanhe Yang, from the division of stroke prevention and heart disease at the US Centers for Disease Control and Prevention. “Both are essential nutrients, which can play central roles in maintaining physiological balance, and both have been linked to the risk of chronic disease. Excess salt consumption increases blood pressure, which can lead to cardiovascular disease, while high salt consumption Potassium can help relax blood vessels and excrete sodium, lowering blood pressure.”
According to Lu Qi, in addition to the relationship with cardiovascular diseases, due to increased blood pressure, excess sodium has already been associated with other changes that can lead to the development of various diseases. “There are many studies suggesting the relationship between salt and chronic inflammation and other patterns that can affect cancer risk, such as promoting cell proliferation,” he says. Now, he intends to deepen the analysis on the association between the ingredient and several chronic ailments, such as diabetes. The scientist is also focusing on a clinical trial to see if reducing the nutrient can improve various aspects of health.
Danger for hypertensive
“Sodium is an essential nutrient, but our need for it is very low, around 0.5g per day — except in very hot temperatures, where large amounts of sweat can lead to increased losses of the mineral. Previous research has shown that the benefit of salt reduction is greatest in people with high blood pressure who are over the age of 50. Japan used to have a very high prevalence of high blood pressure and high rates of stroke. salt intake in the 1970s and now have much lower rates. Stroke remains a major killer in China, which still has a very high salt intake due to the extensive use of soy sauce, which typically contains around 20% salt by weight, as well as many pickled foods. So it’s wise to advise people to restrict the addition of salt to foods.”
Tom Sanders, Professor of Nutrition and Dietetics at King’s College London
Desalting the palate
Despite evidence of the harmful effects of excess salt on health, it is not easy to restrict consumption, as it is one of the most used seasonings in the world. “One of the main barriers to maintaining a low-sodium diet is that people don’t like the taste of unsalted food,” says Misook Chung, a researcher in nursing and nutrition at the University of Kentucky in the United States.
Last month, at the Congress of the European Society of Cardiology, Chung presented a study showing that a taste adaptation intervention can help decrease sodium intake without influencing eating pleasure. “Our pilot study in patients with high blood pressure shows that it is possible to change taste perception and learn to like foods with less salt,” she says. Hypertension affects more than 1 billion people worldwide and is the leading global cause of premature death.
The researchers developed the Sodium Watchers Program to help participants gradually adapt to low-salt foods. Twenty-nine adults with hypertension were randomly assigned to groups. Part received the usual treatment, with dietary advice and medication prescriptions. The other entered the 16-week educational intervention, being accompanied by a nurse via video calls.
Sessions were held weekly for a month and a half, moving to once in 15 days for the next 10 weeks. Participants were given an electronic device that detects salt content so they could identify and avoid foods with a high salt content. “One of the first steps was for patients to notice how much salt they were eating. Using the electronic device, they could test the salt content of restaurant meals and ask the chef to reduce or eliminate salt at the next visit. Within three weeks, most of the participants removed the salt shaker from the table”, reveals Chung.
All participants who entered the intervention group provided a urine sample every 24 hours to assess sodium intake and measured blood pressure. In addition, preference for salty foods and enjoyment of a salt-restricted diet were rated on a 10-point scale. According to Chung, the tapering of the nutrient led “to a significant decrease in sodium intake and increased enjoyment of the salt-restricted diet.”
Research showed that sodium intake dropped by 1,158mg per day, which was a 30% reduction from the start of the program. Meanwhile, in the control group, there was an increase of 500mg in consumption per day. “The enjoyment of a low-salt diet increased in the intervention group, from 4.8 to 6.5 on a 10-point scale, although patients still preferred salty foods,” says the researcher. (DUST)