Kimchi, the Korean traditional fermented food, is not only delicious but also beneficial for health. A new study published in the open access journal BMJ Open suggests that eating up to three daily servings of kimchi may lower men’s overall risk of obesity, while radish kimchi is linked to a lower prevalence of abdominal obesity in both sexes.
Kimchi: a rich source of nutrients and probiotics
Kimchi is made by salting and fermenting vegetables with various flavorings and seasonings, such as onion, garlic, and fish sauce. Cabbage and radish are usually the main vegetables used in kimchi, which contains few calories and is rich in dietary fiber, microbiome-enhancing lactic acid bacteria, vitamins, and polyphenols.
Previous experimental studies have shown that Lactobacillus brevis and L. plantarum isolated from kimchi had an anti-obesity effect. The researchers 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 study: a large-scale analysis of kimchi intake and obesity
The researchers 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 three times a day. Total kimchi included 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 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.
The results: a J-shaped curve for kimchi consumption and obesity
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 one daily serving of total kimchi, participants who ate five 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 three daily servings of total kimchi was associated with an 11% lower prevalence of obesity compared with less than one daily serving.
In men, three 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 one daily serving.
In both sexes, three or more daily servings of kkakdugi kimchi were associated with a 9% lower prevalence of abdominal obesity compared with less than one daily serving.
The researchers caution that their study is observational and therefore can’t establish cause. They also note some limitations, such as the possibility of recall bias in the food frequency questionnaire, the lack of information on the salt content and fermentation time of kimchi, and the potential influence of other lifestyle factors and genetic factors on obesity.
However, they conclude that their findings suggest that “moderate consumption of kimchi, especially baechu and kkakdugi kimchi, may have beneficial effects on obesity.”