A study published in the open-access journal BMJ Open suggests that eating up to three servings of traditional Korean kimchi per day may lower men's overall risk of obesity, whereas radish kimchi is linked to a lower prevalence of belly bulge in both sexes.
To make kimchi, vegetables are salted and fermented together with a variety of seasonings and flavourings such as fish sauce, onion, and garlic.
Cabbage and radish are usually the main vegetables used in kimchi, which contain few calories and are rich in dietary fibre, microbiome-enhancing lactic acid bacteria, vitamins, and polyphenols.
Previously published 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.
They 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 (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, BMI, and waist circumference were measured for each participant. A BMI of 18.5 was defined as underweight; normal weight was 18.5 to 25; and obesity was 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 drink alcohol.
Eating up to three daily servings of total kimchi was linked to an 11% reduced prevalence of obesity than eating less than one daily meal, even after controlling for potentially significant variables.
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.
This is an observational study, and as such, can't establish cause. The researchers acknowledge that food frequency questionnaires can't always accurately identify quantities, added to which the findings may not be generalisable to populations elsewhere in the world.
They also note concerns that kimchi contains salt, high quantities of which aren't good for overall health, although the potassium found in the fermented vegetables may help to counteract this, they suggest.
They caution: “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.”
(With ANI Inputs)
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