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Understanding malnutrition Modules 3 and 4 23-May-17 1 Learning objectives • Be familiar with the various forms of undernutrition and the technical terms that describe them • Understand the consequences of undernutrition for individuals and the impact in growth and development in the society • Understand the reasons for prioritising acute malnutrition in emergencies against other forms of undernutrition • Be aware of who is specifically vulnerable to undernutrition and why. 23-May-17 2 23-May-17 3 Malnutrition includes: – Undernutrition - acute malnutrition (i.e. wasting and/or nutritional oedema), chronic malnutrition (i.e. stunting), micronutrient deficiencies and intra-uterine growth restriction (i.e. poor nutrition in the womb) and – Overnutrition (overweight and obesity). 23-May-17 4 Globally > 35% of under-five deaths are attributable to undernutrition Malaria 1% Measles 1% Pneumonia 15% Diarrhoea 19% Injuries, 3% HIV/AIDS 1% >35% attributable to undernutriti on Other, 19% Causes of Neonatal Deaths Other – 7% Tetanus – 1% Diarrhoea – 1% Sepsis – 17% Neonatal 42% Asphyxia – 23% Congenital – 12% Source: Lancet Series on Maternal and Child Undernutrition, 2008 Preterm – 38% 5/23/2017 5 Undernutrition’s impact on post neonatal child deaths by illness 52% 61% Shaded: Deaths due to undernutrition Total = 53% ~57% ~57% 57% 45% 5/23/2017 9 data Source:Lancet 2005 6 23-May-17 7 What is undernutrition? • Undernutrition occurs when there is – insufficient nutrient intake and/or – an increase of nutrient needs that prevents effective utilization of nutrients (i.e. morbidity) • Nutritional requirements are defined by – Macronutrients: needed in large amounts and include protein, carbohydrate and fat. – Micronutrients: needed in much smaller amounts and include vitamins and minerals 23-May-17 8 Forms of undernutrition • Acute malnutrition (i.e. wasting or presence of bilateral pitting oedema) • Chronic malnutrition (i.e. stunting) • Micronutrient deficiencies 23-May-17 9 Acute malnutrition (1) • Acute malnutrition is characterized by rapid and extreme weight / mass loss and/or bilateral swelling. • Reduces resistance to disease and impairs a whole range of bodily functions • In the early stages can be reversed through adequate food and health care. – Severe weight loss increases the risk of death. 23-May-17 10 Acute malnutrition 23-May-17 11 The burden of undernutrition: Prevalence of SAM in South-central Asia and sub-Saharan Africa Source: ACF International (2010). Taking Action, Nutrition for Survival, Growth and Development, White paper. 23-May-17 12 Chronic malnutrition: Stunting • Chronic malnutrition or stunting is a slow, cumulative process that develops over the long-term as a result of inadequate intake or repeated infections, or both. • The presence of stunting does not necessarily mean that current dietary intake or health is inadequate – the growth failure may have occurred at some time in the past. • By two years of age, stunting may be irreversible. • Chronic malnutrition goes mainly unnoticed and is sometimes referred to as ‘silent malnutrition’ 23-May-17 13 Chronic malnutrition: Underweight • Underweight is a general measure that captures the presence of wasting and/or stunting. It is therefore a composite indicator, reflecting either acute or chronic undernutrition without distinguishing between the two. • When children weigh less than the average weight for children of the same age and sex. 23-May-17 14 The burden of undernutrition: Stunting prevalence worldwide Source: MICS, DHS and other national surveys (2003 – 2008), via UNICEF (2009) Tracking progress on Child and Maternal Nutrition 23-May-17 15 The global burden of undernutrition: underweight 23-May-17 16 The intergenerational cycle of undernutrition 23-May-17 17 The impact of hunger and malnutrition throughout the life cycle Source: ACF International (2010). Taking Action, Nutrition for Survival, Growth and Development, White paper. 23-May-17 18 Micronutrient deficiencies (1) • Micronutrients include all vitamins and the minerals that are essential for life and needed for a wide range of normal body functions and processes but in very small amounts. • The micronutrient requirements of an individual depend mainly on age and sex 23-May-17 19 Micronutrient deficiencies: definitions Definitions Micronutrient malnutrition: The existence of sub-optimal nutritional status due to a lack of intake, absorption, or utilisation of one or more vitamins or minerals. Excessive intake of some micronutrients may also result in adverse effects. Micronutrient deficiency disease (MDD): A clinical disease that arises due to a lack of intake, absorption, or utilisation of one or more vitamins or minerals. Concepts Micronutrient malnutrition can exist even when the energy and macronutrient needs of an individual are met. For that reason it is often referred to as ‘hidden hunger’. People may appear well fed but still be suffering from debilitating and life threatening malnutrition. When certain micronutrients are severely deficient specific clinical signs and symptoms may develop. The classic nutritional diseases such as scurvy, beriberi and pellagra are good examples 23-May-17 of these sorts of disease. 20 Micronutrient deficiencies (2) • Type 1 nutrient deficiencies result in specific deficiency diseases, do not always affect growth, but will affect metabolism and immune competence before signs are apparent. This category of nutrients includes vitamins A, B1, B2, B3, B6, B12, C, D, and folic acid, as well as iron, calcium, copper, iodine, and selenium. 23-May-17 21 Micronutrient deficiencies (3) • Type 2 nutrient deficiencies do not show specific clinical signs. They affect metabolic processes and result in growth failure, wasting, increased risk of oedema, and lowered immune response. • This category of nutrients includes sulphur, potassium, sodium, magnesium, zinc, phosphorus, water, essential amino acids, and nitrogen deficiencies 23-May-17 22 Micronutrient deficiencies (4) • • • • • Iron deficiency leads to iron deficiency anaemia Vitamin C deficiency leads to scurvy Vitamin A deficiency leads to xerophthalmia Niacin or Vitamin B3 deficiency leads to pellagra Iodine deficiency leads to goitre and cretinism (in infants born to iodine deficient mothers) • Thiamin or B1 deficiency leads to beriberi • Riboflavin deficiency leads to ariboflavinosis • Vitamin D deficiency leads to rickets 23-May-17 23 Assessing micronutrient deficiencies • Indirect assessment involves the estimation of nutrient intakes at a population level and from this the risk of deficiency and the likely prevalence (rate) and public health seriousness of MDD • Direct assessment involves the measurement of actual clinical or sub-clinical deficiency in individuals and using that information to give a population estimate of the prevalence of the MDD. 23-May-17 24 23-May-17 25 Who is most vulnerable to malnutrition during an emergency? • The population groups most nutritionally vulnerable can be categorized according to their – physiological vulnerability – geographical vulnerability – political vulnerability – internal displacement and refugee status 23-May-17 26 Physiological vulnerability • Individuals with increased nutrient requirements • Children 0-24 months • Pregnant and lactating women • Individuals with reduced appetite • Older people and disabled, • People with chronic illness, including people living with HIV-AIDS (PLWHA) and TBC 23-May-17 27 The window of opportunity to address malnutrition: the first 2 years of life 23-May-17 28 23-May-17 29 Why acute malnutrition during emergencies? • Rapid onset if compared with other forms • Higher mortality risk, although chronic malnutrition is more prevalent • Much greater potential to be reversed with adequate treatment if detected early enough. 23-May-17 30 Key messages • • • • • • Malnutrition encompasses both overnutrition and undernutrition. The latter is the main focus in emergencies and includes both acute and chronic malnutrition as well as micronutrient deficiencies. Undernutrition is caused by an inadequate diet and/or disease and closely associated with disease and death Acute malnutrition or ‘wasting’ and/or nutritional oedema is less common than chronic malnutrition but carries a higher risk of mortality. It can be reversed with appropriate management and is of particular concern during emergencies because it can quickly lead to death. There are two clinical forms of acute malnutrition: marasmus, which may be moderate or severe wasting; and kwashiorkor which is characterised by bilateral pitting oedema and is indicative of severe acute malnutrition (SAM). Marasmic-kwashiorkor is a condition which combines both manifestations. SAM is associated with higher mortality rates than moderate acute malnutrition (MAM). Chronic malnutrition is the most common form of malnutrition and causes ‘stunting’ (short individuals). It is an irreversible condition after 2 years of age. In general, children are more vulnerable than adults to undernutrition due to their exceptional needs during active growth, and their immature immune and digestive systems (infants 0-6 months). 23-May-17 31