This study investigated advantages and potential risks associated with drinking alcohol in Koreans based on the alcohol flush reaction. Our investigation reviewed published studies and examined moderate-drinking levels for Koreans based on modified National Institute on Alcohol Abuse and Alcoholism guidelines. Fourteen articles out of a total 198 publications were searched using PubMed, EMBASE, KoreaMed, and RISS (Research Information Sharing Service) databases and selected for review. Individuals without alcohol flush reaction (non-flushers) exhibited lower risks associated with insulin resistance, metabolic syndrome, and hyperhomocysteinemia and their 10-year cardiovascular disease risk when alcohol consumption was ≤8 drinks/wk. Conversely, risks associated with insulin resistance, metabolic syndrome, high blood pressure, prediabetes or type-2 diabetes, and high intraocular pressure and increases in carbohydrate-deficient transferrin, gamma glutamyl transferase, and blood glucose levels were present when >8 drinks were consumed. For individuals with flushing reaction (flushers), advantages were reported in relation to risks of hyperhomocysteinemia when alcohol consumption was ≤4 drinks/wk, whereas consumption of >4 drinks/wk increased the risk of insulin resistance, metabolic syndrome, high blood pressure, pre-diabetes or type-2 diabetes, high-risk colorectal adenoma, and high intraocular pressure and increased carbohydrate-deficient transferrin, gamma glutamyl transferase, and blood glucose levels. The moderate drinking level for Koreans is ≤8 drinks/wk for men aged ≤65 years and ≤4 drinks/wk for men aged over 65. For women, these limits should be half of those for men. Furthermore, individuals with flushing reaction should maintain an alcohol consumption level half of that for non-flushers.

The amount of drinking associated with the development of IR in flushers was lower than in nonflushers. Additionally, no positive effect of moderate drinking on IR was observed in flushers. The findings support acetaldehyde-derived mechanisms in the development of alcohol-related IR.