Caffeine intake rises among Korean adults as brewed coffee gains ground

By Tarun Sai LomteReviewed by Susha Cheriyedath, M.Sc.Nov 4 2026

From coffee mixes to specialty brews, a nationwide study of nearly 49,000 adults examines how changing beverage preferences, age, and sex influence South Korea's caffeine habits.

Study: Beverage-based caffeine intake and high consumption trends among Korean adults, 2016–2024: a nationwide population-based study. Image Credit: Marina Demidiuk / Shutterstock

In a recent study published in the journal Frontiers in Nutrition, researchers at Pusan National University Hospital, Republic of Korea, examined temporal trends in beverage-based caffeine consumption in Korean adults.

Caffeine is a commonly consumed psychoactive substance. Moderate intake increases cognitive function and alertness, while excessive intake can lead to undesirable effects (e.g., anxiety and sleep disruption). Moderate intake of caffeinated coffee or tea has been associated with better cognition and reduced dementia risk. But evidence is limited to select populations and single survey waves, and data on long-term temporal trends in the general population are scarce.

About the study

In the present study, the researchers assessed temporal trends in beverage-based caffeine intake in Korean adults. The researchers used data from the Korea National Health and Nutrition Examination Survey (KNHANES) cycles 7–9, conducted between 2016 and 2024. These repeated cross-sectional surveys measured population trends rather than changes within the same individuals. The study included respondents aged ≥ 19 years. Dietary intake was determined using 24-hour dietary recalls, and beverage records were identified using relevant dish codes from KNHANES.

Caffeinated beverages included tea, coffee, cola, energy drinks, and cocoa beverages. Coffee was further classified into instant coffee powder, liquid coffee, roasted capsule or bean coffee, and prepared coffee mixes. Likewise, tea was sub-classified into powdered, infusion-type, and liquid teas. Caffeine intake was calculated from reported beverage volumes using fixed average caffeine concentrations from national monitoring data, applied across survey years. The average daily caffeine intake was estimated by age group, sex, and beverage type. The Rao-Scott chi-square test was performed to compare consumers and non-consumers.

Logistic and linear regression models were used to explore temporal trends in average and high caffeine intake. The team defined high caffeine intake as consuming ≥ 400 mg of caffeine on the recall day. This measure reflected high intake on a single day, not habitual exposure or caffeine-related harm. Further, weighted logistic regression models were used to assess associations between high caffeine intake and participant characteristics. Models were stratified by sex to compare age groups, with adjustment for survey year, body mass index, socioeconomic characteristics, and lifestyle factors.

Findings

The study included 48,991 adults from KNHANES cycles 7–9. About 50.3% of participants were female, 57.9% were overweight or obese, and 42.4% had completed college education or higher. These figures were weighted to represent the national population. Overall, 64.5% of participants consumed caffeine, and 35.5% did not. Consumers were younger, employed, male, and had higher income and education than non-consumers. Mean daily caffeine intake increased linearly by an estimated 1.66 mg/day per calendar year.

While both sexes showed significant upward trends, males consistently had a higher intake and a steeper annual increment (2.2 mg/day/year) than females (1.1 mg/day/year). By age, the average daily caffeine consumption increased significantly among people aged 19–64 years (2.15–2.79 mg/day/year), whereas there was no significant change among those aged ≥ 65 years. In a separate analysis, high caffeine intake increased over time, with odds approximately 5% higher for each calendar year. The odds of high intake also increased among adults aged ≥ 65 years, whose mean intake showed no significant trend.

The upward trend in high caffeine intake was statistically significant among males but not females. Coffee was the primary source of caffeine intake; other beverages contributed less to total intake. 90.8% of caffeine consumers drank coffee. The proportion of caffeine consumers choosing brewed coffee increased gradually over time, while the share choosing coffee mixes declined. The shares choosing ready-to-drink and instant coffee products remained relatively stable over time.

When comparing age groups rather than survey years, males and females aged 30–44 years had significantly higher unadjusted odds of high caffeine intake than those aged 19–29 years. Among males, this association was no longer significant after full adjustment. Among females, it remained significant after adjustment, and those aged 45–64 years also had higher adjusted odds. Adults of both sexes aged ≥ 65 years had considerably reduced odds of high caffeine intake across crude and adjusted models.

Conclusions

The study found sustained increases in average caffeine consumption among Korean adults from 2016 to 2024, alongside increased odds of high caffeine intake across age groups. High intake remained more prevalent among working-age adults and males. Coffee was the primary source of caffeine intake. Consumption shifted from coffee mixes toward brewed coffee, which may differ in serving size and total caffeine delivered.

The researchers suggested that this shift in coffee preferences may partly explain the rise in high caffeine intake, but the study did not directly establish that link. The study's limitations include the cross-sectional design of KNHANES (which precludes causal inference), use of a single dietary recall to estimate caffeine intake (which may not fully reflect habitual consumption), and the exclusion of non-beverage sources of caffeine. Fixed average caffeine concentrations also could not capture differences between brands or preparation methods. Overall, sex- and age-specific guidance, greater consumer education, and improved labeling practices may support informed beverage choices.