Eating up to three servings of kimchi each day could keep the kilos at bay, new research has found.
The traditional Korean dish, which consists of salted, fermented and seasoned vegetables such as cabbage and radish, may lower men's overall risk of obesity, South Korean researchers from Chung Ang University determined. The findings, published on Tuesday in the journal BMJ Open, also established a link between eating radish kimchi specifically and a reduced waistline in both sexes.
Cabbage and radish are usually the main vegetables used in kimchi, which contains few calories and is rich in dietary fibre, microbiome-enhancing lactic acid bacteria, vitamins and polyphenols.
Previously published experimental studies have indicated the lactic acid bacteria Lactobacillus brevis and the probiotic L plantarum - isolated from kimchi - had an anti-obesity effect. The researchers wanted to know if regular consumption of kimchi might also be associated with a reduction in the risk of overall and/or abdominal obesity, which is linked to harmful health outcomes.
The team drew on data from 115,726 middle-aged participants (36,756 men and 78,970 women) aged 40 to 69. The participants were asked to complete a self-reported "food frequency" questionnaire spanning 106 foods; those surveyed would state how often they ate a serving of each item, such as "never", "seldom", or up to three times a day.
Kimchi dishes included in the questionnaire consisted of baechu (cabbage kimchi); kkakdugi (radish kimchi); nabak and dongchimi (watery kimchi) and others, such as mustard greens kimchi. A portion of baechu or kkahdugi kimchi is 50g, while a portion of nabak or dongchimi kimchi is 95g.
Height, weight and waist circumference were measured for each participant. A BMI (body mass index) of 18.5 was defined as underweight; normal weight was defined as 18.5 to 25; and obesity as above 25. Abdominal obesity was defined as a waist circumference of at least 90cm for men and at least 85cm for women; about 36 percent of the men and 25 percent of the women were obese.
Compared with those who ate less than a daily serving of kimchi, participants who consumed five or more servings overall weighed more, had a larger waist size and were more likely to be obese.
The researchers put this down to a higher consumption of kimchi potentially being associated with an overall higher intake of calories, spanning carbohydrates, protein, fat and sodium.
But after accounting for potentially influential factors, eating up to three daily servings of kimchi was associated with an 11 percent lower prevalence of obesity compared with less than one daily serving, the researchers found.
In men, three or more daily servings of cabbage kimchi were associated with a 10 percent lower prevalence of obesity and a 10 percent lower prevalence of abdominal obesity compared with less than one daily serving.
In women, two to three daily servings of cabbage kimchi were associated with an 8 percent lower prevalence of obesity, while one to two servings a day were associated with a 6 percent lower prevalence of abdominal obesity.
Consumption of 25g a day and 11g a day of radish kimchi for men and women respectively was associated with an 8 percent to 11 percent lower risk of abdominal obesity, compared with no consumption.
The researchers acknowledged that as the study was observational, it can't establish cause; they also noted food frequency questionnaires can't always accurately identify quantities and the findings may not be generalisable to other populations elsewhere.
They also noted concerns regarding kimchi's high sodium content but suggested the potassium found in the fermented vegetables may help to counteract this.
"Since all results observed a 'J-shaped' association, excessive consumption suggests the potential for an increase in obesity prevalence. And as kimchi is one of the major sources of sodium intake, a moderate amount should be recommended for the health benefits of its other components," the study concluded.
"Too much kimchi, likely over five servings a day, was associated with a higher risk of obesity, which could be a result of the high salt content or simply a result of eating too much food."
Overall, the researchers deduced between one and three servings per day of any type of kimchi was associated with a lower risk of obesity in men, and a higher intake of radish kimchi was associated with a lower risk of abdominal obesity in men and women.
The research was funded by the Korean government-backed World Institute of Kimchi.
