A study shows an individual’s microbes affect the effectiveness of ginseng when it's consumed.

The Korea Food and Drug Administration commissioned the study to a team led by Professor Kim Dong-hyeon at Kyunghee University.

The team’s survey of 100 Koreans showed a quarter of them experienced insufficient activation levels for beta-glucosidase, which is an enzyme that breaks down the main components of ginseng.

The team said that for people with such levels, ginseng will have few to no benefits.

The food and drug administration advises that people eat vegetables and fermented foods to help activate the enzyme.

The study will be officially announced at the International Symposium on Ginseng in Seoul next month.