New research to be presented at this year’s European Congress on Obesity (ECO 2025, Malaga, Spain, May 11-14) highlights an association between sodium consumption and the risk of both general and abdominal obesity. The study, conducted by Annika Santalahti from the Finnish Institute for Health and Welfare in Helsinki, Finland, and colleagues, provides compelling evidence on the relationship between sodium intake and obesity.
General and Abdominal Obesity: Definitions and Concerns
General obesity is measured using body mass index (BMI), where a BMI of 30 kg/m² or more indicates obesity according to WHO guidelines. Abdominal obesity refers to the accumulation of fat around the abdomen and internal organs, leading to an increased waist circumference. This form of obesity is linked to a heightened risk of cardiovascular disease and other health complications.
Sodium Intake and Obesity Risk
The connection between sodium intake and obesity has been increasingly recognized in recent years. Historically, Finland experienced high sodium consumption and one of the highest heart disease mortality rates in the world, particularly during the 1970s. Although sodium intake has decreased since then, it has remained relatively stable since 2007. Santalahti’s study suggests that, contrary to popular belief, high sodium intake does not predominantly result from unhealthy foods, but rather from everyday food items. In Finland, most of the sodium intake comes from processed meats, bread, dairy products (especially cheese), and other common food sources.
To tackle high sodium intake effectively, the authors emphasize that changes are needed not only at the individual level but also on a broader population scale, requiring cooperation with the food industry.
Study Methodology
The study analyzed data from the National FinHealth 2017 Study, involving 4,014 Finnish adults (men = 2,222, women = 2,792, aged 18 and older). Sodium intake was estimated using a validated food frequency questionnaire, while urine sodium concentration was measured using spot urine samples from a subsample of participants (men = 558, women = 702). BMI and waist circumference were used as indicators of general and abdominal obesity.
Sodium intake and urine sodium concentrations were divided into sex-specific quartiles, and statistical analyses were conducted to account for sociodemographic and lifestyle confounders. Additionally, spot urine samples were compared to 24-hour urine collections for validation.
Key Findings
The study’s results revealed that sodium intake exceeded the WHO’s recommended limit of 5 grams per day in all quartiles except for the lowest quartile of women. In fact, the highest quartile of sodium intake was found to be 2.3 times greater than the lowest quartile for both men and women. The highest sodium intake among men averaged 4,900 mg/day (over 12 grams of salt), while for women, it was 3,750 mg/day (about 9 grams of salt), more than double the recommended daily intake.
The analysis found a significant association between high sodium intake and an increased likelihood of both general and abdominal obesity. For women in the highest quartile of sodium intake, the likelihood of general obesity was 4.3 times greater, and the likelihood of abdominal obesity was 3.4 times greater, compared to women in the lowest quartile. Similar associations were found when urine sodium concentration was used as a marker of sodium intake.
In men, the pattern of obesity risk linked to high sodium intake was similar to women, although statistical significance was not reached for all quartiles. However, when urine sodium concentration was used as an independent variable, men in the highest quartile were 6 times more likely to have general obesity and 4.7 times more likely to have abdominal obesity compared to those in the lowest quartile.
Insights and Implications
The study further suggests that men generally consume more of the foods that contribute to higher sodium intake, such as meat, bread, and cheese. Despite adjusting for total energy intake, the higher salt intake relative to energy intake may explain the stronger association between high sodium intake and obesity observed in men.
The authors stress that the relationship between high sodium intake and obesity remains unclear and warrants further research. Potential biological mechanisms include changes in the secretion of satiety hormones due to long-term high sodium exposure, or the possibility that high sodium intake reflects poor overall nutrition quality, such as the overconsumption of ultra-processed foods.
Furthermore, the food industry plays a pivotal role in reducing population-wide sodium intake. As most sodium comes from processed foods rather than unprocessed primary products, careful attention must be paid to how much sodium is present in commonly consumed foods. Efforts to reduce sodium in the food supply, particularly in widely consumed items like bread and cheese, could have a significant impact on public health.
Conclusion
This study adds to the growing body of evidence linking high sodium intake with obesity risk. Both dietary sodium and urine sodium concentration showed strong associations with general and abdominal obesity, particularly among women. The authors call for a deeper understanding of the biological mechanisms underlying this relationship and emphasize the need for broader public health interventions to reduce sodium consumption, particularly through collaboration with the food industry.
As the research continues, it will be important to investigate how changes in dietary sodium might improve obesity outcomes, as well as the potential role of the broader food environment in shaping public health.
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