This is a study to evaluate the effects of a prebiotic, AHCC, a standardized extract of cultured Lentinula edodes mycelia, on immunologic markers and the incidence of respiratory tract infections in children.
Children aged 2-4 years old at the time of enrolment
Good nutritional status with weight-for-height > -2, and height-for-age z-score > -2 based on WHO growth standards
Infants in a group setting (daycare centers).
No congenital disorder
Presence of chronic illnesses or conditions (congenital disorder, genetic syndromes, congenital heart disease, chronic renal failure, cystic fibrosis, etc)
Children who have participated in another clinical intervention study within the past 30 days.
Children who are likely to be transferred to another facility that is not part of the study before completing the follow-up period