Children in low and middle income countries need vitamin A supplements
A new study suggests that children in low and middle income countries should be given vitamin A supplements to prevent death and illness. According to the study vitamin A supplements for these children could save 600,000 lives a year.
The researchers argue that the effectiveness of vitamin A supplementation is now so well-established that further trials would be unethical, and they urge policymakers to provide supplements for all children at risk of deficiency.
The study was published online on August 25, 2011 in the British Medical Journal (BMJ).
Vitamin A is an essential nutrient that must be obtained through diet. Natural sources of vitamin A include cod liver oil, carrot, broccoli and spinnach. Vitamin A plays important role in visual cycle, skin health and in regulating gene transcrption in most tissues. Cells uptake retinol, a form of vitamin A, and oxidize to retinal (retinaldehyde) and then to retinoic acid. Retinoic acid regulates gene transcription by binding to nuclear receptors known as retinoic acid receptors.
Vitamin A deficiency in children increases vulnerability to infections like diarrhoea and measles and may also lead to blindness. Globally, the World Health Organisation estimates that 190 million children under the age of 5 may be vitamin A deficient. But, despite widespread efforts, vitamin A programmes do not reach all children who could benefit.
So a team of researchers based in the UK and Pakistan analysed the results of 43 trials of vitamin A supplementation involving over 200,000 children aged 6 months to 5 years. Differences in study design and quality were taken into account to minimise bias. They found vitamin A supplements reduced child mortality by 24% in low and middle income countries. It may also reduce mortality and disability by preventing measles, diarrhoea and vision problems, including night blindness. According to the paper, seventeen of the 43 trials including 194 483 participants reported a 24% reduction in all cause mortality (rate ratio=0.76, 95% confidence interval 0.69 to 0.83). Seven trials reported a 28% reduction in mortality associated with diarrhoea (0.72, 0.57 to 0.91).
The authors say that, if the risk of death for 190 million vitamin A deficient children were reduced by 24%, over 600,000 lives would be saved each year and 20 million disability-adjusted life years (a measure of quantity and quality of life) would be gained.
Based on these results, the authors strongly recommend supplementation for children under 5 in areas at risk of vitamin A deficiency. They conclude: "The evidence for vitamin A is compelling and clear. Further trials comparing vitamin A with placebo would be unethical."
This view is supported in an accompanying editorial by two experts at Harvard School of Public Health, who say "effort should now focus on finding ways to sustain this important child survival initiative and fine tune it to maximise the number of lives saved."
Source article: Vitamin A supplements for preventing mortality, illness, and blindness in children aged under 5: systematic review and meta-analysis. Evan Mayo-Wilson, Aamer Imdad, Kurt Herzer, Mohammad Yawar Yakoob, and Zulfiqar A Bhutta. BMJ 2011;343:d5094 doi:10.1136/bmj.d5094 (Published 25 August 2011).