Evidence shows that they cut the chance of diarrhoea and pneumonia without any risk of worsening the HIV infection, according to a report in The Lancet.
Questions had been raised over the use of zinc because HIV thrives on zinc for its structure and to help it penetrate immune cells and reproduce. Zinc also activates the body cells that are targeted by HIV - T lymphocytes.
But the work by Dr William Moss and colleagues at Johns Hopkins School of Public Health, in Baltimore, suggests any safety fears are unfounded.
They recruited 96 children, aged between 6 months and five years, from Grey’s Hospital in Pietermaritzburg, South Africa, and randomly assigned the children to receive zinc supplements or a dummy drug each day for six months.
The zinc supplements did not result in an increase in blood HIV viral load - a measure of HIV severity - but the children receiving zinc did have less diarrhoea.
Dr Moss said : "Few interventions are available to reduce morbidity in children with HIV-1 infection in resource-poor countries.
Although UNAIDS, the World Health Organisation and their partners are committed to providing antiretroviral therapy to 3 million people by the end of 2005, he said many children still did not have access to this treatment or drugs to prevent opportunistic infections.
"Consequently, more than half these children die before the age of three years, most commonly of respiratory tract infections and diarrhoeal diseases.
"Zinc supplementation could be a simple and cost-effective intervention to reduce morbidity and mortality in children with HIV-1 infection."
A spokeswoman from the HIV/Aids charity AVERT said : "The findings of this trial are certainly encouraging, as diarrhoea can be a life threatening illness in HIV positive children.
"However, further studies in both zinc-deficient and non zinc-deficient children would be desirable before any decision was made to recommend zinc supplementation as standard practice.
"There is now an internationally agreed commitment to increase antiretroviral treatment access for children, and while this study is interesting, we must be careful not to allow its findings to shift attention away from this aim of supplying universal access to antiretroviral therapy for all children who need it."
People with a healthy, balanced diet should not normally be deficient in zinc.
Foods rich in zinc include fish, meat, cheese, some nuts and seeds and brown rice.