REDUCING THE RISK OF CANCER
Epidemiological studies suggest that zinc deficiency may be associated with increased risk of cancer.
HIV AND AIDS
Low plasma zinc concentration occurs in HIV infection, especially with advancing illness. The balance of evidence favours the view that a low plasma zinc level is a marker for disease progression. Large intervention trials are not available to determine whether zinc supplementation in HIV infection produces positive outcomes.
Zinc supplementation (10 mg elemental) randomly allocated to preschool children residing in a malaria-endemic region of Papua New Guinea for 5 days a week over 45 weeks showed this intervention reduced morbidity due to Plasmodium falciparum. Duggan et al (2005) also identified low plasma zinc levels in children with acute malaria, including a significant correlation between evidence of illness severity and zinc status.
A randomised, controlled trial involving 270 children aged between 5 and 12 months, hospitalised with pneumonia, found that those given 20 mg/day of zinc (as acetate) showed significant reductions in recovery time from severe pneumonia. Overall hospital stay duration was also reduced when used with standard antimicrobial therapy. Furthermore, a randomised, placebo-controlled trial in which 1555 children aged less than 12 months were given 70 mg of zinc prophylactically found a reduced incidence of pneumonia (17%), with severe pneumonia incidence reducing by 49%. It also reduced URTI by 8% and reactive airways disease (bronchiolitis) by 12%.
Patients with diagnosed Wilson’s disease have increased hepatic glutathione and reduced oxidation when supplemented with zinc sulfate (220 mg three times daily) for 3 months, compared with those using penicillamine.
Cognitive performance was temporarily improved after 3 months of zinc supplementation (zinc chelate 15 mg) taken twice daily by six subjects with Alzheimer’s disease. Although the initial improvement was not maintained in this small open study, a modest cognitive improvement on psychometric testing was observed at 12 months for the four patients evaluated.