Diet and Skin: What the Evidence Says

A popular idea holds that the Korean table, with its kimchi, fermented foods, vegetables and tea, explains the skin Korea is known for. It is a pleasant story, and food is central to this site, but the research is much less tidy than the story. This page sets out what studies do and do not show.

Where the research is strongest: acne

Most of the human evidence on diet and skin concerns acne. The American Academy of Dermatology says diet may play a role but that the evidence is limited. Small studies have found that low-glycemic diets reduced acne, while others found no link. Some studies connect cow's milk, including skim milk, to more breakouts, and the reason is unclear. The AAD states that more research is needed and that diet alone does not clear acne.

A 2018 systematic review and meta-analysis pooled 14 observational studies covering 78,529 people aged 7 to 30. It found higher odds of acne with any dairy (odds ratio 1.25) and with milk (1.28), and a stronger association for low-fat or skim milk than whole milk. The authors cautioned that results should be read carefully: the studies varied widely, there was evidence of publication bias, many relied on self-reported acne, and most analyses were unadjusted, meaning other differences between people could explain part of the link. Observational studies of this kind cannot show cause. Note that the AAD page and the meta-analysis do not fully agree on yogurt and cheese, a sign of how unsettled the picture is.

These findings concern teenagers and young adults in the studies pooled; they do not amount to a verdict on any national cuisine. "The Korean diet" is also not one pattern, as the balanced Korean meal and Korean diet research both show.

Probiotics and fermented foods

Because kimchi, doenjang and other fermented foods contain microbes, it is tempting to assume they help skin. Research on probiotics is real but early. A recent scoping review mapped 523 reports on oral probiotics, prebiotics and synbiotics and skin, 401 of them on probiotics. Atopic dermatitis was the best-studied area, but the authors did no quality-of-evidence rating and warned against reading the many positive results as strong evidence. Reporting was patchy: 29 percent of human intervention studies did not name the strain, 30 percent gave no dose, and only 8 percent reported participants' diets.

For acne, the review found 10 randomized trials averaging 92 participants, 9 of which reported at least one positive effect on severity. It also noted that no meta-analysis existed and that probiotics do not appear in the 2024 AAD acne guidelines. Trials test specific strains in defined doses, which is a different thing from eating a bowl of kimchi, so these results cannot be translated into a food claim. This page does not rest any claim about skin on kimchi, vegetables or tea; traditional teas and vegetables and namul are covered for their place at the table, not as skin treatments.

Why comparisons mislead

Comparing skin across countries tangles diet with many other things. Sun exposure and sunscreen habits differ, as described in sunscreen culture. So do skincare routines, discussed in the K-beauty routine, along with climate, age, genetics, smoking and sleep. Because these factors travel together, no one ingredient can be credited for how someone's skin looks.

A food-first reading

What survives scrutiny is modest. Eating a varied diet with plenty of vegetables, whole grains and fewer sugary drinks is good for general health, and sugar in Korean food offers a realistic look at where sweetness sneaks in. The AAD suggests noticing whether particular foods seem to trigger breakouts for you. For persistent skin problems, a dermatologist is the right person to ask, and food is not a substitute for care.