Between 2,000 and 4,000 children between the ages of eight and 17 may be suffering from anorexia in Ireland.
A new report by 'BMJ Open' estimates that 95 children are diagnosed with anorexia in Ireland every year - 11 of which are aged between eight and 12.
The HSE said eating disorders, especially anorexia, have the highest mortality rate of all mental illnesses.
Report author Professor Sarah Byford said there has been an increase in young people affected by the disease.
Ms Byford said: "Overall for all children aged eight to 17, they tell us that anorexia nervosa diagnosis remains very similar over the last 10 years.
"However, if we look just at the younger children, those aged eight to 12, there has been an increase.
"Anorexia nervosa is most common in adolescents and teenagers aged between 15 and 16 so most of the services will be set up for teenagers. What we need now is to make the services also able to deal with younger children."