NEW ORLEANS — Keeping the salt shaker off the kitchen table might just help you live longer, according to a new study. Researchers at Tulane University say adding salt to your meals regularly could lead to an earlier death.
The study reports that men lose 1.5 years and women 2.28 years at the age of 50 versus people who never or rarely add salt. Diners who always add salt to their food had a 28 percent higher risk of dying prematurely.
The study is based on more than half a million British adults who have been giving their lifestyles and health statistics to the UK Biobank. Generally, about three in a hundred people ages 40 to 69 die prematurely, scientists say. The increased risk from adding salt suggests one more person will meet an earlier death in that group.
“To my knowledge, our study is the first to assess the relation between adding salt to foods and premature death,” says Lu Qi, of Tulane University School of Public Health and Tropical Medicine, in a statement. “It provides novel evidence to support recommendations to modify eating behaviors for improving health. Even a modest reduction in sodium intake, by adding less or no salt to food at the table, is likely to result in substantial health benefits, especially when it is achieved in the general population.”
Assessing overall salt consumption is notoriously difficult because many foods, particularly pre-prepared and processed foods, have a lot of salt in them before they even make it to the table. Studies that use urine tests to measure salt intake don’t necessarily reflect this and, moreover, some foods that are high in salt can also be eaten with food that is high in potassium, like fruit and vegetables, which is good for us.
Potassium is known to protect against the risk of heart conditions and metabolic diseases like diabetes, whereas sodium increases the risk of conditions like cancer, high blood pressure and stroke. That’s why the researchers chose to look at whether people added salt to their food at the table, regardless of what was added in cooking or preparing the meal.
Hold the salt
For their data, the researchers analyzed metrics from 501,379 Biobank participants. When joining the study between 2006-2010, the participants were asked via a touchscreen questionnaire whether they added salt to their foods with the options: never/rarely, sometimes, usually, always or prefer not to answer. Those who answered prefer not to answer were not included in the analysis.
The researchers also took into account factors like age, sex, race, deprivation, body mass index, smoking, alcohol intake, physical activity, diet and medical conditions like diabetes, cancer and heart and blood diseases. They followed the participants for an average of nine years and premature death was defined as being before 75 years.
“Adding salt to foods at the table is a common eating behavior that is directly related to an individual’s long-term preference for salty-tasting foods and habitual salt intake,” says Qi. “In the Western diet, adding salt at the table accounts for 6-20 percent of total salt intake and provides a unique way to evaluate the association between habitual sodium intake and the risk of death.”
As well as finding that always adding salt to foods was linked to a higher risk of premature death from all causes and a reduction in life expectancy, the researchers found that these risks tended to be reduced slightly in people who consumed the highest amounts of fruit and vegetables, although these results were not statistically significant.
“We were not surprised by this finding as fruits and vegetables are major sources of potassium, which as protective effects and is associated with a lower risk of premature death,” adds Qi. “Because our study is the first to report a relation between adding salt to foods and mortality, further studies are needed to validate the findings before making recommendations.”
Too little sodium not great for you either
In an editorial to the paper, Annika Rosengren, a senior medical researcher at the University of Gothenburg, Sweden and who was not involved with the research, notes that the net effect of a drastic reduction in salt consumption remains controversial. “Given the various indications that a very low intake of sodium may not be beneficial, or even harmful, it is important to distinguish between recommendations on an individual basis and actions on a population level,” she writes. “Classic epidemiology argues that a greater net benefit is achieved by the population-wide approach (achieving a small effect in many people) than from targeting high-risk individuals (a large effect but only achieved in a small number of people).
“The obvious and evidence-based strategy with respect to preventing cardiovascular disease in individuals is early detection and treatment of hypertension, including lifestyle modifications, while salt-reduction strategies at the societal level will lower population mean blood pressure levels, resulting in fewer people developing hypertension, needing treatment, and becoming sick,” she continues. “Not adding extra salt to food is unlikely to be harmful and could contribute to strategies to lower population blood pressure levels.”
A strength of Prof Qi’s study is the large number of people included. However, it does have some limitations, such as the possibility that adding salt to food shows an unhealthy lifestyle and lower socio-economic status, although analyses attempted to adjust for this. Also there was no information on the quantity of salt added. Adding salt may be related to total energy intake and intertwined with intake of other foods. Participation in the UK Biobank is also voluntary and therefore the results are not representative of the general population, so further studies are needed to confirm the findings in other populations.
South West News Service writer Danny Halpin contributed to this report.