In a cross-sectional study, researchers from Chung Ang University and elsewhere analyzed the data from the HEXA cohort study in Korea to investigate the association between kimchi consumption and obesity among Korean adults. They showed that total kimchi consumption of 1-3 servings/day is inversely associated with the risk of obesity in men. Also, in men, a higher intake of baechu kimchi (cabbage kimchi) was related to a lower prevalence of obesity and abdominal obesity. A higher consumption of kkakdugi (radish kimchi) was associated with lower prevalence of abdominal obesity in both men and women. However, since all results showed a ‘J-shaped’ association, excessive consumption suggests the potential for an increase in obesity prevalence.
Kimchi is traditionally consumed as a side dish in Korea and manufactured by salting and fermenting vegetables with various flavouring and seasoning ingredients, including onion, garlic, red pepper powder, salted shrimp and fish sauce.
Cabbage and radish are usually the main vegetables in kimchi, and kimchi is low in calories and rich in dietary fiber, lactic acid bacteria, vitamins and polyphenols.
Fermented kimchi contains major species of lactic acid bacteria, such as Leuconostoc spp., Lactobacillus spp. and Weissella spp.
Especially, Lactobacillus spp. is the dominant species of kimchi lactic acid bacteria in late fermentation.
Previously published experimental studies have shown that Lactobacillus brevis and Lactobacillus plantarum isolated from kimchi had an anti-obesity effect.
And Chung Ang University researcher Hyein Jung and colleagues wanted to know if regular consumption might be associated with a reduction in the risk of overall and/or abdominal obesity, which is considered to be particularly harmful to health.
The scientists drew on data from 115,726 participants (36,756 men; 78,970 women; average age 51) taking part in the Health Examinees (HEXA) study.
HEXA is a large, community-based long term study of the larger Korean Genome and Epidemiology Study, designed to examine environmental and genetic risk factors for common long term conditions among Korean adults over the age of 40.
Dietary intake for the previous year was assessed using a validated 106-item food frequency questionnaire for which participants were asked to state how often they ate a serving of each foodstuff, from never or seldom, up to 3 times a day.
Total kimchi included baechu; kkakdugi; nabak and dongchimi (watery kimchi); and others, such as mustard greens kimchi.
A portion of baechu or kkahdugi kimchi is 50 g, while a portion of nabak or dongchimi kimchi is 95 g.
Height and weight, for BMI, and waist circumference were measured for each participant. A BMI of 18.5 was defined as underweight; normal weight 18.5 to 25; and obesity as above 25.
Abdominal obesity was defined as a waist circumference of at least 90 cm for men and at least 85 cm for women. Some 36% of the men and 25% of the women were obese.
The results indicated a J-shaped curve, possibly because higher consumption is associated with higher intake of total energy, carbohydrates, protein, fat, sodium and cooked rice, say the researchers.
Compared with those who ate less than 1 daily serving of total kimchi, participants who ate 5 or more servings weighed more, had a larger waist size, and were more likely to be obese.
They were also more likely to not be highly educated, have a low income, and to drink alcohol.
But after accounting for potentially influential factors, eating up to 3 daily servings of total kimchi was associated with an 11% lower prevalence of obesity compared with less than 1 daily serving.
In men, 3 or more daily servings of baechu kimchi were associated with a 10% lower prevalence of obesity and a 10% lower prevalence of abdominal obesity compared with less than 1 daily serving.
In women, 2-3 daily servings of this type of kimchi were associated with an 8% lower prevalence of obesity, while 1-2 servings/day were associated with a 6% lower prevalence of abdominal obesity.
Eating below average quantities of kkakdugi kimchi was associated with around a 9% lower prevalence of obesity in both sexes.
Consumption of 25 g/day for men and 11 g/day for women was associated with an 8% (men) to 11% (women) lower risk of abdominal obesity compared with no consumption.
“Since all results observed a ‘J-shaped’ association, excessive consumption suggests the potential for an increase in obesity prevalence,” the authors said.
“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 findings appear in the journal BMJ Open.
H. Jung et al. 2024. Association between kimchi consumption and obesity based on BMI and abdominal obesity in Korean adults: a cross-sectional analysis of the Health Examinees study. BMJ Open 14: e076650; doi: 10.1136/bmjopen-2023-076650