To fight the freezing winter, who doesn’t love to heat up with a bowl of soup? And a series of studies, the most recent among Japanese men, suggest that this soup may have health benefits besides just warding off the cold.
A Japanese study in the January issue of the Journal of the American Dietetic Association found that the frequency of soup intake is inversely associated with BMI, waist circumference, and waist-to-hip ratio. This finding adds to previous studies in France, Italy, and Portugal that found the same relationship between soup intake and BMI. One study even showed that Portugese girls aged 5 to 10 years with high soup consumption were less likely to be overweight.
However, despite these negative correlations, our understanding of soup’s true influence on obesity and other metabolic factors remains just as unclear as your favorite clam chowder.First, these studies did not evaluate the causal relationship between soup intake and obesity-related parameters such as BMI. Therefore, it is unclear if soup intake influences obesity directly or indirectly. Possible hypotheses include that soup has a satiety-inducing effect leading to reduced caloric intake. Research has shown that soup increases plasma cholecystokinin (CCK) levels. CCK, along with acting on the stomach to increase fat and protein digestion, can also act on the central nervous system to induce a feeling of fullness. Another theory is that the ingredients in soups, such as miso (soybean) and vegetables, decrease obesity-related parameters. Yet, more research needs to be done.
Additionally, unlike previous studies in European countries, this Japanese study showed no significant negative correlation between the frequency of soup intake and blood pressure or total cholesterol levels. It is also somewhat counterintuitive that increased soup consumption would decrease blood pressure since soup intake is often associated with higher salt consumption.
Further studies definitely need to clarify the association between soup intake and metabolic risk factors. Yet, one finding remains constant no matter which side of the world you’re on: soup intake is inversely correlated to BMI. So, while the scientific details remain murky, the next time you defrost with a bowl of soup, perhaps it is doing more than simply keeping you warm.