What Does Zinc Do?

A child eating from a spoon

Children need zinc to grow and develop. Zinc is a mineral that is important for immune function, wound healing, and the senses of smell and taste.

When Does My Child Need Zinc? And How Much?

Zinc is important at all stages of your child’s development. When your child is about 6 months old, you can start giving solid foods with zinc to your child.

Children 7 to 24 months need 3 mg of zinc each day.

Once My Child Starts to Eat Solid Foods, How Can I Make Sure My Child Gets Enough Zinc?

It is important to choose foods that contain zinc. Examples of foods with zinc include:

• Zinc-fortified grains (for example, zinc-fortified infant cereals)
• Meats (for example, beef or pork)
• Dairy (for example, yogurt or cheese)
• Fishexternal icon (for example, flounder)
• Shellfish (for example, oysters or crab)
• Legumes (for example, beans)

Foods with zinc are especially important for babies who are fed only breast milk. Levels of zinc in breast milk are high after birth and go down over the first 6 months. After 6 months, it is important to introduce foods with zinc to meet nutritional needs.

ZINC ADMINISTRATION ALONE OR IN COMBINATION WITH OTHER MICRONUTRIENTS

The clear benefits have raised questions about the most appropriate use of zinc. Should it be used as a single therapy, or should it be combined with other minerals and vitamins, especially when used in a dietary supplement or a food fortificant? Answering these questions will require additional research to validate the most effective products for children, especially for long-term use. However, for use in treating children with diarrhoea, the safety and benefits of zinc alone are clearly defined, and recommendations for its use are compelling. We, thus, feel that programmes to implement the re-commendations of WHO/UNICEF need to be scaled up as rapidly as possible, even while research continues to identify the best products for dietary supplementation or fortification. It should be noted that recent efforts to combine zinc with iron/folic acid in East Africa, an area with high rates of malaria, found higher rates of hospitalization and mortality in children who received the combined supplement (65). Such combinations may, thus, need to be examined more closely to assure freedom from adverse events.

SCALING UP ZINC AS A TREATMENT FOR CHILDHOOD DIARRHOEA

The greatest challenge facing health researchers, practitioners, and funding agencies is how to translate the proven effectiveness of zinc as a treatment into action that will benefit the lives of young children, particularly those living in conditions of chronic poverty and malnutrition. In 2003, ICDDR, B launched the Scaling Up Zinc for Young Children (SUZY) Project with the aim of setting Bangladesh on the path to providing all under-five children with diarrhoea with zinc treatment, irres-pective of gender, income, or geographic location. To attain this goal, the SUZY Project has been organized around five key activities: (a) registration, production, and distribution of zinc tablet, (b) promotion among healthcare providers and mass media campaign, (c) training of professionals and introduction of zinc treatment into public, private and NGO delivery systems, (d) formative and operations research in support of scaling up, and (e) knowledge transfer from Project findings.

With regard to registration and production, the Project decided to pursue the scaling up of a dispersible, 20-mg zinc sulphate tablet (which is now known as ‘Baby Zinc’ in Bangladesh), as recommended by WHO. The tablet is placed in a spoon or a small cup and water added which leads it to disperse into a sweet, vanilla-flavoured syrup that masks the taste of zinc. The treatment is packaged in a 10-tablet blister pack, and caretakers are instructed to give one tablet per day for 10 days. It was not known at the time of launching whether young Bangladeshi children would find the tablet formulation acceptable, whether caretakers could correctly adhere to treatment instructions. This was studied in rural and urban settings, with findings indicating that the formulation was highly acceptable and that treatment instructions were easily followed. Ninety-eight percent of caretakers prepared the syrup correctly; over 90% perceived that their children found the taste to be acceptable, and the tablets were given, on average, for eight days (66). There were also concerns regarding side-effects associated with the formulation. As already described, it was found that the formulation is associated with a transient increase in the risk of vomiting, but with no adverse clinical consequences (64).

Formative studies were undertaken that involved caretakers of children with an active case of diarrhoea, healthcare providers (licensed and unlicensed), drug vendors, and medical representatives (drug salesmen). A recent baseline survey conducted throughout Bangladesh showed that most (>90%) consultations of healthcare providers for a childhood diarrhoea episode involve the private sector (67). This survey also confirmed the disparities in care received, favouring households with higher wealth, and those living in urban settings. This has led the SUZY Project to develop a promotion strategy that emphasizes awareness-building in the private sector, but also sensitization and training programmes for the government (public) and NGO sectors. The formative caretaker and provider interviews have led to the development of a frequently-asked databank. Some more frequently-asked questions and responses are found in the Appendix.

CURRENT ISSUES AND FUTURE RESEARCH PRIORITIES

Healthcare-delivery systems

To reach all children with diarrhoea, zinc treatment will need to be introduced and sustained within the public, private and NGO service-delivery systems. Each of these systems has its unique set of strengths and weaknesses that must be taken into account in the planning stages. Unanswered questions include whether or not zinc treatment can be introduced through community health workers or depot-holders, the impact of over-the-counter availability of zinc on the use of health services, and the misuse of zinc for untested disorders, such as acute respiratory tract infections, poor growth, and loss of appetite.

Financing

As a preventive measure, treatment of childhood diarrhoea with zinc has been estimated to be one of the most cost-effective interventions available. Nonetheless, because of the shear frequency of childhood diarrhoea, the costs either at the household level or those assumed by the public or private sector could be substantial. It remains to be demonstrated what the longer-term impact of a successful scaling-up campaign will be. It is reasonable to assume that an initial investment in zinc treatment will eventually lead to deceased expenditure on other drugs, particularly antibiotics, and the costs avoided by preventing episodes of future illness. Until these assumptions are verified and appropriate information is disseminated, decision-makers will be reticent to commit public or other subsidized financial resources, e.g. NGO clinics. A further constraint faced by the private sector, particularly the pharmaceutical industry, is the current lack of sound data upon which to estimate demand and pricing of product.

Combining zinc and iron

Iron and zinc deficiencies commonly coincide in early childhood. The obvious conclusion is to treat both the conditions simultaneously. It is not yet clear whether or not this combined approach should be made a public-health policy; in fact, there is now concern about using iron routinely in malaria-endemic areas. It is known that, in children receiving zinc therapy, levels of serum iron are adversely affected. Evidence is also emerging that, while children are receiving iron supplementation, the effects of zinc supplementation in terms of reduced morbidity are cancelled out—at least in areas with high rates of malaria. It will, therefore, be important to test alternative supplementation and zinc-treatment strategies and confirm these results in the desired beneficial effects prior to establishing policies in favour of combined supplementation. Finally, it may be the case that combined therapies will have a differential impact based upon the nutritional status of a child and the severity of his/her micronutrient status. This requires further study.

Impact on diarrhoea-management practices and use of drugs: As zinc treatment is introduced, what will happen to existing diarrhoea-management practices? Will zinc be added to existing treatments, such as ORS (desired) and antibiotics (not desired)? Will providers and drug vendors view zinc as an opportunity or as a threat, and for what reasons? Given the first national scaling up of zinc is occurring in Bangladesh, it is difficult to predict how this will influence current practices, thus the importance of having in place the capacity to monitor for the potential desired and undesired changes in management practices.

Home management of childhood diarrhoea

Caretakers in Bangladesh lead the world in the use of ORS. We need to build upon this success as zinc treatment in childhood diarrhoea is introduced through mass media and promotion. Given that zinc will be available over-the-counter in stores without prescription, caretakers will have easy access to it. The challenge will be to develop and confirm the effectiveness of public education that aims at improving home-management practices.