Regularly adding table salt to food linked to 41% higher risk of stomach cancer

Stomach cancer - also known as gastric cancer - is the fifth most common cancer in the world. Although it is not as common in the United States, it still accounts for about 1.5% of new cancers diagnosed each year.

Doctors and experts are interested in identifying risk factors for stomach cancer so people can receive quality treatment at an early stage.

A recent study published in the journal of Gastric Cancer analyzed data from more than 470,000 people to find out how the frequency of adding salt to food is associated with cases of stomach cancer.

Main results of the study

The study authors found that participants who always added salt to their food had a higher risk of stomach cancer compared to participants who rarely or never added salt to their food.

This study adds evidence on the risk that salt poses for stomach cancer in non-Asian populations, as most studies in this area have been conducted in Asian populations.

Research methodology

This prospective study used data from the UK Biobank and included 471,144 participants in the analysis.

They excluded participants who had missing data on dietary salt intake, body mass index (BMI), or urinary sodium or potassium levels. Participants who were diagnosed with cancer or kidney disease at baseline were also excluded.

Participants completed baseline questionnaires indicating how often they added salt to their food, excluding salt used in cooking. Participants could answer: never/rarely, sometimes, usually or always.

The researchers also measured levels of sodium, creatinine and potassium in the participants' urine. They were also able to assess 24-hour urinary sodium excretion.

They controlled for several covariates, including physical activity levels, age, education level, ethnicity, gender, and alcohol use. They also took into account consumption of red meat and fruits and vegetables. The median follow-up period for participants was 10.9 years.

Results

During the observation period, 640 cases of stomach cancer were recorded among participants. Overall, participants who always added salt to their food at the table were more likely to be former or current smokers, have high levels of alcohol consumption, and have lower levels of education.

Researchers found that participants who always added salt at the table had a 41% higher risk of stomach cancer compared to participants who never or rarely added salt to their food at the table.

Limitations of the study

This study has several limitations. First, it cannot prove that high salt intake causes stomach cancer. It also relies on participants' self-reporting, which does not always provide the most accurate information, and they did not have complete dietary salt intake data.

The UK Biobank also does not necessarily reflect the general population, so studies with other groups with greater diversity may be warranted and the results may not be generalizable. The association between salt intake and stomach cancer risk may be stronger than observed in this study.

Tips for reducing salt intake

These findings support the idea that excess salt intake is associated with an increased risk of stomach cancer. However, there are many other reasons to limit your salt intake, such as reducing the risk of high blood pressure and kidney problems.

People may want to make smarter salt choices to reduce their overall salt intake.

Expert opinion

Anton Bilchik, MD, a surgical oncologist and director of the gastrointestinal and hepatobiliary disease program at Providence Saint John Cancer Institute in Santa Monica, California, who was not involved in this study, told Medical News Today: "This study provides further evidence of a link between a diet, especially one high in salt, and stomach cancer."

He added: “One of the main causes of stomach cancer in Asian countries is believed to be high-salt fish. Much less is known about the relationship between salt intake and stomach cancer in Western countries. It is well known that excessive salt intake is associated with a higher risk of hypertension and cardiovascular disease. This study provides further evidence that salt consumed regularly in food increases the risk of developing stomach cancer. It is therefore important that people are aware of the harmful effects of excess salt consumption."