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What is the role of micronutrients in nutrition?

Micronutrients – also known as vitamins and minerals – are essential components of a high-quality diet and have a profound impact on health. While they are only required in tiny quantities, micronutrients are the essential building blocks of healthy brains, bones and bodies.

Consuming a diverse range of nutrient-dense foods alongside breastfeeding is the ideal way for young children to get essential micronutrients in their diets. But in many parts of the world, children’s diets contain insufficient micronutrients and deficiencies are widespread.

Micronutrient deficiencies are often referred to as ‘hidden hunger’ because they develop gradually over time, their devastating impact not seen until irreversible damage has been done. While a child may go to sleep each night with a full belly, micronutrient deficiencies mean that his or her body is still hungry for good nutrition.

Millions of children suffer from stunted growth, cognitive delays, weakened immunity and disease as a result of micronutrient deficiencies. For pregnant women, the lack of essential vitamins and minerals can be catastrophic, increasing the risk of low birth weight, birth defects, stillbirth, and even death.

What are the main deficiencies?

Iodine deficiency is the primary cause of preventable brain damage in children. Its most devastating impacts occur during foetal development and in the first few years of a child’s life. Globally, 30 per cent of the world’s population live in areas with iodine deficiency1.

Vitamin A deficiency affects about one third of children living in low and middle income settings, mainly in sub-Saharan Africa and South Asia2. Vitamin A deficiency weakens the immune system and increases a child’s risk of contracting and dying from infections like measles, and diarrhoeal illnesses.

Iron deficiency can lead to anaemia, which increases the risk of haemorrhage and bacterial infection during childbirth and is implicated in maternal deaths. In turn, babies may be born prematurely and suffer from infections, learning disabilities, and delayed development. Almost 40 per cent of pregnant women and more than 40 per cent of children under 5 in developing countries are anaemic3. About half of these cases are estimated to result from iron deficiency.

Zinc deficiency impairs immune function and is associated with an increased risk of gastrointestinal infections. It is also a contributing factor in child deaths due to diarrhoea. Zinc deficiency is especially common in lower income countries due to the low dietary intake of zinc-rich foods and inadequate absorption.

Calcium, vitamin D, and folate deficiencies are a particular concern during pregnancy, and can lead to a number of health complications for both the mother and growing baby.

How are micronutrient deficiencies prevented and treated?

UNICEF supports the following strategies to prevent and treat micronutrient deficiencies in women in children:

Dietary diversification strategies help families access a range of nutrient-rich foods. They involve educating caregivers on appropriate infant and young child feeding practices and improving the use of locally available foods.

Supplementation programmes provide specific micronutrients that are not available as part of the regular diet. Supplementation is especially important at times when the body has particularly high micronutrient needs – for example during pregnancy – that are difficult to meet with diet alone. One example is iron and folic acid supplements for pregnant women, which can reduce the risk of low birth weight, maternal anaemia and iron deficiency.

Mass fortification is the process of adding micronutrients to foods or condiments that are consumed regularly by the population, such as flour, sugar, salt and cooking oils. Fortification programmes are extremely effective in preventing micronutrient deficiencies at minimal cost – often only a few cents per person per year. Universal salt iodization and flour fortification programmes (to add iron) have provided successful mass fortification in many countries.

Home fortification programmes provide caregivers with micronutrient powders to sprinkle on the foods they prepare for children at home. This can significantly improve the dietary quality of complementary food for children from 6 months to the age of 2 or older. Home fortification empowers caregivers and provides them with the tools to improve the family diet without requiring a major change to their dietary practices.

These strategies, together with the prevention and treatment of infectious diseases and deworming, can minimize micronutrient depletion and reduce micronutrient deficiencies among vulnerable groups.

What are the challenges?

Micronutrient deficiencies are caused by immediate factors – such as inadequate intake of nutritious foods and infectious disease – and underlying factors – like poverty and unhealthy environments. Addressing these factors can be a challenging process.

Increasing dietary intake of nutritious foods can be challenging because micronutrient-dense foods are often expensive and not readily accessible. To illustrate, iron deficiency is the most pervasive nutritional problem in the world but progress to eliminate it has been limited, in part, because iron-rich foods – like liver, red meats, eggs, fish, whole-grain bread, and legumes – are not widely available or affordable to many families.

Infectious disease and micronutrient deficiencies exacerbate one another in a vicious cycle. Infections deplete micronutrients at a time when the body needs them the most. With limited stores to draw upon, the immune system weakens further and becomes less capable of fighting the infection.

Underlying factors, such as inadequate care practices and an unhealthy household environment, including unsafe drinking water and poor sanitation, also threaten food intake and increase infections.

Reaching the most vulnerable populations of women and children is also a challenge, particularly during the critical 1,000 day developmental period from pregnancy to a child’s second birthday.

How is UNICEF responding?

UNICEF’s response to micronutrient deficiencies spans both development and emergency contexts.

Improving dietary diversity

Providing supplementation

  • To reduce child mortality, UNICEF supports vitamin A supplementation programmes for children aged 6-59 months in priority countries (those with high under-five mortality rates or where deficiencies are a public health problem). Supplements are often delivered during ‘Child Health Days’ alongside other high-impact health interventions such as vaccination and deworming. These events are particularly effective at reaching vulnerable children in hard-to-reach communities, and in fragile settings with weak health systems.
  • UNICEF advocates for the importance of iron folic acid supplementation during pregnancy and supports governments to scale up this intervention. UNICEF worked with partners to develop the multiple micronutrient formulation tested in different settings to reduce anaemia and improve pregnancy outcomes4, and is now working with partners to develop global guidance on this intervention.

Supporting universal salt iodization

  • UNICEF advocates and guides national governments and private sector salt producers in implementing universal salt iodization.
  • As a member of the Iodine Global Network, UNICEF contributes to policies and standards in iodine nutrition.

Promoting other forms of mass fortification

  • In addition to salt, UNICEF supports national governments to develop food fortification programmes for vitamin A, iron and folic acid. An important part of this work involves advocating for legislation to make food fortification mandatory, ensuring access for the widest population possible.
  • Globally, UNICEF works to shape the global food fortification agenda and provide guidance on improving monitoring systems.
  • As a member of the Food Fortification Initiative Executive Management Team, UNICEF contributes to the global strategy for fortifying industrially milled wheat flour, maize flour, and rice. http://ffinetwork.org/

Supporting home fortification programmes

  • UNICEF is a leading supporter of home fortification programmes worldwide. This involves supplying micronutrient powders, advocating for the adoption of relevant policies, creating demand and behaviour change strategies to reach target populations, and ensuring that programmes are rigorously monitored and evaluated.
  • UNICEF co-chairs the global Home Fortification Technical Advisory Group, a global network of stakeholders tasked with providing support on the implementation of effective home fortification programmes.




1 Iodine Global Network, www.ign.org
2 Stevens et al, Lancet Global Health, 2015: 3: e528-36
3 Stevens et al; Lancet Global Health 2013 July: e16-25
4 Multiple Micronutrient Supplementation During Pregnancy in Developing Country Settings, Food and Nutrition Bulletin 2009 Volume 30, Issue 4 - http://www.ingentaconnect.com/content/nsinf/fnb/2009/00000030/a00404s4/art00010



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