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New study to explore the unintentional overdosing of vitamin A


Newcastle University academic Dr Georg Lietz has been awarded $2.1M by the Bill & Melinda Gates Foundation to assess the safety of vitamin A programs targeted at children in developing countries.

Approximately one-third of children in low-income countries are deficient in vitamin A, and an estimated 157,000 children worldwide die each year because of vitamin A deficiency.  To address this problem, vitamin A has been added to our diets for decades, either as supplements or via fortification programmes, and has significantly decreased morbidity and mortality among pre-school children in many parts of the world.

These programs offer a highly cost-effective way of combatting a serious public health problem.  However, in some countries, the intake of vitamin A may now be excessive because it is being added to many foods and is provided routinely in the form of high potency supplements.

Newcastle University nutritionist Dr Georg Lietz will lead an international team to assess the risk of unintentional overdosing with vitamin A.  The aims of the project will be to determine the safe upper levels of vitamin A intake and to provide guidance and recommendation for future nutrition programmes.

“The serious health problems associated with a lack of vitamin A are well-documented, particularly in low income countries,” explains Dr Lietz, based in the University’s  School of Agriculture, Food and Rural Development.

“Vitamin A fortification programmes are a cheap and effective way of improving child health and have made a huge difference to millions of lives.  But a lack of co-ordination means there are now many overlapping schemes and in some areas, children are getting well above the recommended daily dose of the vitamin.”

“The aim of this project is to identify children at high risk of excess vitamin A intake due to overlapping intervention programmes.  We hope to properly assess exactly how much vitamin A children are getting on a daily basis and what the associated risks are.  This in turn will inform new guidelines about where and when vitamin A should be added to food.”

The effects of vitamin A

Vitamin A – retinol – and its derivative retinoic acid are essential for normal growth and development and for the functioning of the immune system. Since vitamin A deficiency is a serious public health problem, governments and the private food sector have supplied the mostly affected population groups, i.e. pregnant and breast-feeding women and pre-school aged children, with high dose supplements, micronutrient powders and fortified foods such as margarine, sugar, milk, flour oils and bouillon cubes.  

“In the Philippines, over 150 foods are fortified with Vitamin A, while in Bangladesh we are seeing children who are receiving both supplements and fortified products, with some children having daily intake levels well above the recommended limits,” says Dr Lietz.

Excessive levels of the vitamin can lead to nausea, dizziness, bone and joint pain and in severe cases liver failure and haemorrhage.

Professor Lietz and his team will study children under the age of five in three areas; the Philippines, Bangladesh and Guatemala.

Monitoring both dietary and biochemical assessments, the team will assess liver and bone function parameters as well as vitamin A status using state of the art isotope dilution techniques. 

Professor Lietz added: “I am hugely grateful to the Foundation for this grant.  It is vital that we understand the implications of adding supplements to food and the guidelines that need to be in place to ensure they benefit our health rather than damage it.”

published on: 24 March 2015