Galvanising policy-makers to tackle zinc deficiency

Zinc deficiency is one of the top ten contributors to the disease burden in developing countries with high mortality. South-East Asia and sub-Saharan Africa are the worst hit. How should policy-makers tackle this problem?

Researchers from the UK Institute of Child Health and UNICEF review current evidence on the public health uses of zinc. The balance of research suggests that:

• Zinc supplements improve the outcomes of children with diarrhoea.
• Regular zinc supplements can also prevent childhood diseases, including diarrhoea, coughs, pneumonia and malaria.
• Supplements may also prevent growth failure. This effect is greatest in those with low birth weights, stunted growth or zinc deficiency.

Until recently the World Health Organisation had only recommended increasing zinc intakes as part of food mixes to treat severe malnutrition. The WHO and UNICEF now recommend a 20 mg soluble zinc tablet for daily use in diarrhoea treatment and propose to distribute blister packs of ten tablets.

The most effective delivery system is not yet clear, however, but this approach seems better than adding zinc to oral rehydration solution (ORS) mixes, which is an untested option for diarrhoea treatment, and many countries promote the use of home made ORS. However, health services already find it difficult to achieve and maintain high levels of coverage of current treatments, such as ORS, and will face similar challenges distributing zinc.

Health planners have three options for providing zinc on a regular basis:

• supplementation
• fortification – the addition of zinc to foods
• increasing the intake of foods rich in zinc.

The researchers warn that zinc should not be promoted as a single supplement for prevention, as many people in developing countries suffer from multiple micronutrient deficiencies. Plus zinc, iron, vitamin A and copper all potentially interact when used as single supplements. Trials are underway to test the usefulness of a combined micronutrient supplement during infancy, and for mothers during pregnancy and lactation, which could replace currently recommended iron and folate tablets used in the treatment of anaemia.

So far, experience of fortification in developing countries is limited to iodised salt and iron-fortified what flour and the risks of interactions between micronutrients in fortified food are unknown. Developing zinc fortification in countries with the highest mortalities will require innovative strategies, including small scale community approaches.

The most sustainable long-term approach would be to improve people’s diets. High protein foods tend to contain the most zinc, with greater availability in animal than plant foods. Plant breeding programmes are trying to increase zinc concentrations and availability in cereals. Health educators can encourage household cooking methods that increase zinc availability in grains and beans, including sprouting, fermenting and soaking. However, this complex behaviour change will take time.

Overall, the researchers warn against overloading health systems with a new single nutrient programme to provide zinc. Instead it should be delivered through existing channels and integrated into existing programmes, such as those for diarrhoeal disease or anaemia control.

Source(s):
‘Zinc deficiency: what are the most appropriate interventions?’, British Medical Journal 330: 347-349, by R. Shrimpton, R. Gross, I. Darnton-Hill and M. Young, 2005

Funded by: UNICEF

id21 Research Highlight: 31 May 2005

Further Information:
Roger Shrimpton
Centre for International Child Health
Institute of Child Health
London WC1N 1EH
UK

Tel: :
Contact the contributor: Roger.Shrimpton@ich.ucl.ac.uk

Institute of Child Health, University of London, UK

UNICEF

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