Extra pounds can also be fought by eating. Foods rich in fibre, prebiotics and probiotics, low in fat and calories, help to satiate us while keeping calorie intake to a minimum, stimulate the metabolism and reduce hunger. Some, such as fish, legumes and wholemeal carbohydrates, we are all familiar with. Others are more exotic, but are gradually making their way into the diet of Italians too. This is the case of kimchi, the fermented vegetables that are a must on Korean tables, and are increasingly common on Western ones too: a Korean study just published on Bmj Open reveals that the consumption of at least three portions of kimchi per day seems to be linked to a reduction important risk of becoming obese.
Fermented vegetables
Kimchi is a traditional food in Korean cuisine, served as a side dish with virtually every meal, and also used as an ingredient in soups, meat and fish dishes. It is prepared with vegetables preserved in salt, to which various seasonings are added (among which chilli pepper stands out), and then left to ferment for at least a few days (but there are varieties aged for up to a year).
This controlled fermentation process guarantees the presence of the famous good bacteria, typically lactobacilli, excellent for the health of our intestinal microbiota, and linked by various laboratory research to anti-obesity effects. However, it was not clear whether consuming kimchi regularly was enough to benefit from the positive effects of lactobacilli on body weight. For this reason, three Korean researchers got to work.
I study
The research was carried out using data collected from the Health Ecaminees (or Hexa) study, which is investigating the link between genetic and environmental risk factors in the development of various chronic diseases in the Korean population. Drawing on this database, the researchers obtained detailed information on the daily diet of over 115 thousand South Korean citizens, accompanied by data on their health and body weight.
By analyzing this data, researchers identified the beneficial effects of kimchi: consuming at least three 50-gram portions per day was associated with an 11% reduction in the risk of obesity, compared to those who consumed one portion or less. There is a but to keep in mind, however, because the association that emerged shows what experts define as a “J-curve”, that is, a trend whereby daily consumption is beneficial only up to a certain point: from 5 portions in fact, from day to day, kimchi begins to be associated with a greater risk of obesity.
How much kimchi per day?
Probably – explain the authors of the study – this is due to the fact that kimchi is a side dish enjoyed with other dishes, which often contain meat and carbohydrates, and therefore those who eat a lot, and are therefore more likely to gain weight, in Korea also end up consume more kimchi than average. In the same way, however, it is good to remember that this is an observational study, which can only identify a statistical association but cannot causally demonstrate that kimchi helps prevent weight gain, and that the study was carried out in a population with very different from ours, and therefore the results may not be valid everywhere.
Kimchi is also a food rich in sodium, and therefore alongside the beneficial effects of good bacteria it is good to consider the harmful effects of salt, which should never be present in excessive doses in our diet. So what message can we draw from the research? While waiting for further studies, it is probably best to advise the curious (ever more numerous given the current passion for Korean culture and cuisine) to moderate consumption of kimchi, remembering that a couple of portions alone already contain a good part of the quantity of salt that we can eat every day. Salt aside, however, it is an absolutely healthy food, capable of improving cardiovascular health, combating inflammation, and if the results of the new study prove correct, even helping us keep extra pounds under control.