- What is Malnutrition
- Statistics on Malnutrition
- Risk Factors for Malnutrition
- Progression of Malnutrition
- Symptoms of Malnutrition
- Clinical Examination of Malnutrition
- How is Malnutrition Diagnosed?
- Prognosis of Malnutrition
- How is Malnutrition Treated?
- Malnutrition References
What is Malnutrition
Malnutrition is a condition in which an individual has insufficient energy to maintain their body’s essential functions, including growth, maintenance and movement. It is defined by the British National Institute for Clinical Excellence as “a state in which a deficiency of energy, protein and/or other nutrients causes measurable adverse effects on tissue/body form, composition, function or clinical outcome.” As the definition suggests, malnutrition can be further classified as either protein-energy/protein-calorie malnutrition (i.e. a deficiency in protein energy), or micronutrient deficiency (i.e. a deficiency in one or more micronutrients), depending on the specific nature of the nutritional intake/expenditure imbalance. These two sub-types of malnutrition commonly coexist.
Primary malnutrition refers to malnutrition which is caused by inadequate energy intake. This condition often occurs in relation to food insecurity or when adequate food is not available (in terms of total calories or specific micronutrients). It can also result from poor appetite due to illness or eating disorders such as anorexia nervosa.
Secondary malnutrition arises when an individual’s dietary intake is sufficient, but energy is not adequately absorbed by the body as a result of infectious conditions such as diarrhoea, measles or parasitic infections, or medical or surgical problems affecting the digestive system. Malnutrition can also occur as a result of increased metabolic demands following illness or surgery.
Malnutrition is strongly associated with ill health, as both a cause and consequence. Individuals who are malnourished are more susceptible to disease and infection due to impaired immune function, and tend to consult health practitioners more frequently and take longer to recover from episodes of illness or injuries. Illness, and particularly long episodes of illness, can also frequently result in malnutrition, as individuals tend to eat and drink less when they are ill.
Statistics on Malnutrition
Malnutrition affected some 148 million children around the world in 2007, although the vast majority of malnourished children resided in developing countries. In Australia, the 2007 Child Nutrition Survey reported some 5% of children were underweight for their height. In addition the survey revealed that, in a substantial proportion of children, daily intake of some micronutrients was insufficient to meet the children’s development needs, indicating the potential for micronutrient deficiencies. For example, calcium intake was insufficient in more than half of all 9-16 year old, while some 15% of 14-16, 6% of 9-13 and 7% of 2-8 year old children did not consume the average requirement for iodine estimated by the National Health and Medical Research Council. Substantial proportions of children in the 14-16 year age group also consumed less than the estimated average requirement for vitamin A, folate, phospohorous, magnesium, iron and zinc.
In England, an estimated 5% of the general population is malnourished, although prevalence is much higher in specific sub groups. In Australian adults, malnutrition has typically been studied in specific subgroups with a high risk of malnutrition, for example hospital inpatients, the elderly and individuals undergoing chemotherapy. A 1997 study in two Sydney hospitals found that 36% of patients admitted to hospital were malnourished. Studies from Britain also indicate that malnutrition and some micro-nutrient deficiencies are common amongst the elderly. For example, amongst elderly individuals in aged care homes, an estimated 35% are deficient in folate and 40% deficient in vitamin C.
Indigenous Australians are also at increased risk of malnutrition due to their typically low socioeconomic status and associated difficulties accessing food. Up to 30% of Indigenous Australians report that being able to access food is a concern to them at least some of the time, indicating that this proportion of the population are at high risk of becoming malnourished. Indigenous women are also more than twice as likely to bear low birth weight infants, demonstrating a higher prevalence of malnutrition in pregnant indigenous women than in the general population of pregnant women in Australia.
Risk Factors for Malnutrition
Malnutrition occurs throughout the world, however a number of geographic and demographic groups have an increased risk of becoming malnourished. Overall, individuals who reside in developing countries are more likely to suffer from malnutrition than those who reside in developed countries, due to the higher prevalence of poverty and infectious disease in developing nations. However, there are a number of factors which may predispose an individual to malnutrition, regardless of their area of residence.
In general, factors which affect adequate nutrition include:
- Poverty: Individuals from low socio-economic backgrounds and particularly those living in poverty are more likely to be malnourished than individuals from higher socio-economic classes. This is most often primary malnutrition a result of food insecurity (being unable to access adequate sources of nutrition to meet the body’s daily demands). Secondary malnutrition (stemming from infectious disease) is also more prevalent in situations of poverty due to overcrowding and poor sanitation (which for example increase the risk of infection) and contributes to the increased incidence of malnutrition amongst the poor.
- History of or recent infectious and parasitic disease, in particular diarrhoea, malaria, or intestinal worms predisposes an individual to malnutrition and these conditions reduce the proportion of nutrients which the body is able to consume;
- History of recent surgery, particularly surgery involving the gastrointestinal system may increase an individual’s risk of malnutrition.
- Medications: A number of medications, for example medications used in chemotherapy, can reduce an individual’s appetite or lead to eating difficulties (e.g. difficulty swallowing) and therefore predispose an individual to malnutrition.
- Chronic diseases for example HIV is often associated with reduced appetite and food consumption (usually resulting from toxic medication regimes) which in turn causes malnutrition.
Children and adolescents
In children and adolescents factors which predispose malnutrition include:
- Low birth weight: Individuals born with a low birth weight are more likely to suffer malnutrition throughout their life and are unlikely to “catch-up” in terms of growth.
- Adolescent mothers: Children who were born to adolescent mothers are more likely to be malnourished than those born to older women, as during adolescence, a young woman’s body is still developing and the additional stress of pregnancy at this time creates an extremely high risk of the child being born at a low birth weight.
- Not being breastfed: Breast milk is the ideal food for an infant as it is nutritionally balanced and provides antibodies which strengthen the developing infant’s immune system reducing the chance of infectious and other diseases which can lead to malnutrition. Children who are not breastfed therefore have a higher risk of becoming malnourished.
In adults factors which can predispose an individual to malnutrition include:
- Age: Elderly individuals are more likely to suffer from malnutrition than their younger counterparts. For example, patients who were admitted to two Sydney hospitals in a malnourished state were eight years older than individuals who were admitted in an adequately nourished condition.
- Being unable to prepare food: Individuals who are reliant on external help to prepare meals (e.g. the elderly) are less likely to meet their daily nutritional requirements, as food may not be available when they wish to eat it, or may not be prepared to their requirements.
- Pregnancy and lactation: Pregnant and breastfeeding women experience increased metabolic demands, as a result of the demands of their growing foetus or feeding child. For this reason they have a higher risk of becoming malnourished than non pregnant or non breastfeeding women.
- Alcohol or drug abuse: are associated with reduced appetite, as well as reduced absorption of specific micronutrients. Alcohol or drug abuse therefore creates an increased risk of malnutrition.
Progression of Malnutrition
Malnutrition which is related to poverty often begins early in life, or even in utero (when the foetus is developing in a woman’s uterus), and continues throughout the lifecycle. A child who is malnourished early in life is likely to have their growth retarded as a result, and is unlikely to ever “catch-up” in terms of their body size. As adults, they will be shorter and weigh less than their adequately nourished counterparts.
In many cases malnutrition also has inter-generational effects. For example, a woman who suffered from malnutrition as a child, is more likely to bear underweight infants (infants weighing less than 2.5kg) and low birth weight infants are more likely to suffer nutritional problems throughout their lifecycle.
Malnutrition also commonly begins or worsens following a period of illness, when an individual is unable to eat or drink sufficient amounts of energy to fulfill their daily needs. This in turn reduces the body’s immune function, leading to longer periods of illness and inadequate food consumption. This is particularly true amongst the elderly.
Symptoms of Malnutrition
There are a range of symptoms associated with malnutrition.
Malnutrition in children may lead to illness (e.g. diarrhoea, acute respiratory infection) as a result of reduced immune function. It is also commonly associated with reduced appetite, developmental regression and low levels of physical activity.
In adults malnutrition can also result in illness, eating difficulties or suppressed appetite.
Clinical Examination of Malnutrition
If a health professional suspects a child is underweight, they are most likely to measure the child’s weight and height, to determine whether or not the child is an appropriate weight for their height. They may measure a child’s head circumference and/or mid-upper arm circumference. Practitioners may also look out for the following signs as indicators of malnutrition:
- Short stature;
- Thin arms and legs;
- Visible rib cage or vertebrae;
- Wasted buttocks; and/or
- Poor skin and hair condition.
When malnutrition is suspected in adults, a health professional will measure the patient’s BMI. A BMI less than18.5kg/m2 indicates current malnutrition while a BMI less than 20kg/m2 indicates an individual is underweight, at an increased risk of becoming malnourished and is potentially already malnourished. Other physical appearances which may indicate to a health professional that an adult is malnourished include:
- Loose fitting clothes;
- Fragile skin;
- Poor wound healing; and/or
- Wasted muscles.
Patients who are diagnosed with malnutrition should receive prompt treatment. Those who are not malnourished but at risk of future malnutrition should receive nutritional counseling and be scheduled for repeat screening.
How is Malnutrition Diagnosed?
A child will be diagnosed as malnourished if their weight is low for their height. An adult will be diagnosed with malnutrition if they have a BMI less than18.5kg/m2.
Prognosis of Malnutrition
Malnutrition is a condition with far reaching health and social consequences, particularly if it is not promptly treated.
In both children and adults the effects of malnutrition include an increased risk of:
- Illness and infection: Individuals who are malnourished are more likely to become ill or infected due to the reduced capacity of their immune system associated with malnutrition.
- Mortality: A study of patients admitted to two Sydney hospitals found that those who were malnourished at the time of admission were more likely to die in the following twelve months than those who were not malnourished at the time of admission. Malnutrition is also a contributing factor in more than half of all childhood deaths globally.
The effects of chronic malnutrition during childhood include an increased risk of:
- Cognitive development disorders: Children who are chronically under nourished may have difficulty learning and concentrating while they are malnourished, and this can impair their mental development both at the time of malnutrition and in the future.
- Stunted growth: Malnutrition also affects a child’s physical growth, and a child who is malnourished for a significant time at any point, is likely to become stunted (short for their age during childhood and of short stature as an adult).
- Regressive development: Malnutrition can lead to regressive development. For example, a child who began walking may then stop walking again.
- Susceptibility to chronic diseases: Evidence suggests that malnutrition during pregnancy or early childhood malnutrition leads to an increased risk of chronic disease such as diabetes, coronary heart disease and renal failure later in life.
In adults the effects of malnutrition include an increased risk of:
- Low birth weight offspring: The offspring of women who are malnourished are more likely to suffer from growth retardation as a foetus and be born at a low birth weight. This in turn increases the likelihood of early childhood illness and death, as well as the likelihood that the offspring will suffer from malnutrition.
- Lengthy hospital admission: An Australian study reported that patients who were malnourished at the time of hospital admission were admitted for an average of six days more than adequately nourished admissions.
- Reduced muscle capacity is associated with malnutrition and can reduce an individual’s capacity to perform tasks, particularly strenuous tasks, as well as increase their susceptibility to falls and other injuries.
- Menstrual irregularities: Women who are malnourished are more likely to experience irregular or absent menstrual cycles, which can in turn lead to fertility problems.
- Impaired psychosocial function: There are a range of psychosocial consequences of malnutrition including an increased risk of depression, lack of self-esteem and poor body image, lack of appetite, disinterest in social activities and loss of libido.
How is Malnutrition Treated?
Treating malnutrition often involves interventions from a range of health professionals which, depending on the specific nature of the individual’s malnutrition, may include:
- Dieticians may be involved in screening and assessment of the patient’s nutritional status, determining their daily energy requirements as well as provision of nutritional supplements as required;
- Pharmacists may provide prescription food supplements;
- Laboratory specialists may be involved in monitoring the individual’s progress, for example checking for side effects to feeding supplements or monitoring an individual’s response to micronutrient therapy;
- Nurses are often the main point of contact with hospital in-patients and play a pivotal role in identifying individuals with potential nutritional deficiencies and monitoring their eating patterns (e.g. observing meal times);
- Hospital doctors and GPs may be involved in the ongoing monitoring of the individual’s nutritional status as well as treating associated conditions (e.g. diarrhoea);
- Care assistants may offer feeding or psychosocial support to malnourished patients.
Malnourished children need immediate attention. Children who display signs of mild or moderate malnutrition may remain in the care of their parents/guardians, but will probably need to return to a health facility for future weight checks. In cases where malnutrition is severe, children will most likely be admitted to hospital for treatment.
Health professionals will discuss the child’s condition and habits with their parents/guardians. Discussion will include the child’s eating habits and any potential barriers to nutritious food intake (e.g. financial circumstances, cultural beliefs which prevent the consumption of certain foods) which may affect the parent’s ability to adequately nourish their child.
A health professional will probably also provide counseling regarding appropriate infant and child feeding patterns, for example the importance of breastfeeding, preparation of infant foods, the importance of micronutrients and appropriate meal sizes for children. They are also likely to advise that malnourished children benefit from physical contact, structured playtime, physical activity and maternal involvement throughout their treatment.
Treatment of severe malnutrition is best carried out in hospital. In the first week it typically focuses on stabilising the child through the provision of intravenous feeding and treating any coexisting complications. For example, wide spectrum antibiotics are often prescribed to prevent infection, rehydration is usually, glucose is commonly given to prevent hypoglyaecemia (low blood sugar) and electrolytes and micronutrients given to balance or increase required concentrations in the child’s body.
The focus then shifts to rehabilitating the child and feeding is cautiously reintroduced, usually in the form of specially prepared, protein-energy and nutrient rich formulas, when the child’s appetite returns. Feeding is usually performed regularly (i.e. every four hours) until the child gains sufficient weight to be discharged.
Prior to a child being discharged, a health professional will usually provide the parents with advice about appropriate feeding and preventative intervention, including giving high energy foods and supplements, ensuring children are immunised and given six monthly vitamin-A supplements. Parents are also likely to be advised of the need for daily structured play, and follow up visits to a clinic to check weight and development.
In the majority of adult cases, malnutrition will be treated by ensuring the availability of nutritious food, advising the patient regarding nutritional eating habits and developing an eating plan which meets the patient’s nutritional requirements. In determining an eating plan for the patient, their daily energy requirement in terms of total protein energy and micronutrients should be determined. A health professional will also consider any additional metabolic demands the individual may have, due to illness or injury, which may require oral nutritional supplements (e.g. vitamin supplements). Counseling usually encourages malnourished patients to:
- Consume energy and protein rich foods (e.g. cream, butter);
- Eat three meals plus three snacks per day;
- Consume nourishing beverages such as fruit juice and smoothies;
- Take micronutrient supplements if required.
Health professionals should also be able to provide referrals if help obtaining or preparing food is needed. They will attempt to refer to an agency which can provide a needing individual with nutritionally appropriate food is prepared in such a way that they can consume it (e.g. precooked for those unable to prepare their own food, of the right consistency for those who have difficulty chewing or swallowing).
In more severe cases of malnutrition, food supplements may be required to ensure an individual consumes their daily nutritional requirements in terms of total energy and micronutrients. A practitioner may consider prescribing food supplements in cases where the patient has:
- A BMI less than 18.5kg/m2;
- Lost more than 10% of total body weight in the past 3-6 months;
- A BMI less than 20kg/m2 and has lost more than 5% of total body weight in the last 3-6 months;
- Eaten little or nothing for the past five days or are unlikely to eat for the next five days;
- Increased nutritional needs due to reduced absorption, nutrient losses or increased metabolic needs.
There are a range of methods by which supplements can be administered, and wherever possible, they are administered via the gastrointestinal tract either in the form of:
- Food fortification, for example provision of micronutrient fortified bread, which may be administered in inpatient or community settings (in conjunction with adequate monitoring and support) for individuals with specific micronutrient deficiencies;
- Proprietary oral nutritional support, for example provision of micronutrient tablets, may be administered in inpatient or community settings (in conjunction with adequate monitoring and support) for individuals with specific micronutrient deficiencies;
- Enteral tube feeding (providing nutritionally complete food directly to the gut via a tube) may be administered in inpatient or community settings (in conjunction with adequate monitoring and support) and used either alone or in conjunction with oral nutrition for patients who are unable to consume their daily nutritional requirements orally.
In cases where gastrointestinal feeding is not possible (e.g. intestinal failure), nutritional support may be given via parenteral nutrition (intravenous infusion of nutrients).
Nutritional supplements, whether delivered orally, enterally or intravenously should be planned by a professional with training in nutrition support. Daily supplements will be planned to reflect the patient’s daily nutritional demands, taking into consideration additional requirements which may arise with, for example, severe malnutrition, reduced absorption or additional demands related to surgery.
|For more information on nutrition, including information on types and composition of food, nutrition and people, conditions related to nutrition, and diets and recipes, as well as some useful videos and tools, see Nutrition.|
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