Kimchi, a beloved staple of Korean cuisine, is not just a dish, but a cultural icon. Its unique preparation involves the fermentation of vegetables like cabbage and radish, combined with seasonings such as onion, garlic, and fish sauce. This fermentation process not only preserves the vegetables but also enhances their nutritional value, making kimchi a low-calorie, high-fibre, and vitamin-rich food. The presence of microbiome-friendly lactic acid bacteria and beneficial polyphenols further contribute to its health benefits.
Recent experimental studies have spotlighted certain strains of bacteria found in kimchi, such as Lactobacillus brevis and L. plantarum, which exhibit potential anti-obesity effects. To explore this further, researchers investigated whether regular kimchi consumption might correlate with reduced risks of overall and abdominal obesity, both significant health concerns.
The data for this study were meticulously collected from the Health Examinees (HEXA) study, a robust research initiative involving a substantial sample size of 115,726 participants (36,756 men and 78,970 women, average age 51). This community-based, longitudinal study is part of the larger Korean Genome and Epidemiology Study, which aims to identify environmental and genetic factors influencing chronic conditions among Korean adults over 40. The comprehensive nature of this study ensures the reliability of the findings.
Participants’ dietary habits were assessed using a 106-item food frequency questionnaire, which captured their consumption patterns over the previous year. Various types of kimchi, including baechu (cabbage), kkakdugi (radish), Babak, dongchimi, and others, were quantified based on typical portion sizes.
Anthropometric measurements such as height, weight (used to calculate BMI), and waist circumference were recorded. Obesity was defined by a BMI exceeding 25, while abdominal obesity was indicated by waist circumferences of at least 90 cm for men and 85 cm for women. Notably, 36% of men and 25% of women in the study were classified as obese.
The study’s findings revealed a unique ‘J-shaped’ association between kimchi consumption and obesity. While higher kimchi consumption was associated with increased intake of energy, carbohydrates, protein, fat, sodium, and rice, moderate consumption showed significant benefits. Participants who consumed up to three daily servings of kimchi demonstrated an 11% lower prevalence of obesity compared to those consuming less than one serving daily. This ‘J-shaped’ association underscores the importance of moderation in kimchi consumption for health benefits.
Among men, consuming three or more daily servings of baechu kimchi was associated with a 10% lower prevalence of obesity and abdominal obesity. In women, consuming two to three daily baechu kimchi was linked to an 8% lower prevalence of obesity, while one to two servings correlated with a 6% lower prevalence of abdominal obesity.
Lower-than-average consumption of kkakdugi kimchi showed around a 9% lower prevalence of obesity in both sexes. Daily intake of 25 grams among men and 11 grams among women was associated with an 8% to 11% reduction in abdominal obesity risk compared to non-consumers.
The study’s observational nature precludes establishing causation, and limitations include potential inaccuracies in self-reported dietary intake and the study’s applicability primarily to Korean populations. Concerns over kimchi’s sodium content were noted, although the potassium content in fermented vegetables may mitigate these effects.
Researchers caution against excessive kimchi consumption due to its potential to increase obesity prevalence, particularly highlighting its role as a significant source of dietary sodium. They recommend moderate consumption to maximise the health benefits associated with its nutritional components.
More information: Hyein Jung et al, 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. DOI: 10.1136/bmjopen-2023-076650
Journal information: BMJ Open Provided by BMJ Group
