5 Nutrition

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Contents

Unit 11: Nutrition

Objectives

At the end of this unit you should be able to:

11-1 What is good nutrition?

Nutrition is the food (nutrients) we eat (our diet). A well-balanced diet provides the correct amount of both macronutrients and micronutrients which are needed for healthy growth and development. This is good nutrition.

Good nutrition is the correct amount of a well-balanced diet for healthy growth and development.

11-2 What are macronutrients and micronutrients?

Nutrients are the building blocks in food which people need for the growth, maintenance of all body tissues and the normal functioning of all body processes. Nutrients can be divided into 2 groups:

The body needs both macronutrients and micronutrients to be healthy.

11-3 What is a well-balanced diet?

A well-balanced diet provides good nutrition. It consists of a wide range of good foods that provide adequate amounts, but not too much, of macronutrients and micronutrients for good health. In contrast, “junk” food often provides too much or too little of one or more nutrients.

Examples of good food are:

Common examples of bad food are sweets, salted chips and cool drinks. Every effort must be made to help people access affordable good foods and avoid bad “junk” foods.

11-4 What is malnutrition?

Malnutrition (bad nutrition) means too much or too little macronutrients or micronutrients. Note that malnutrition does not only mean too little food. Malnutrition may be due to either over-nutrition or undernutrition and can result in health problems.

Malnutrition may be due to too much or too little food.

Note
The World Health Organisation defines malnutrition as “deficiencies, excesses or imbalances” in the diet. Malnutrition may also result from poor absorption or loss of one or more nutrients from the gut.

11-5 Are there different types of malnutrition?

Yes. It is helpful to think of 3 types of malnutrition:

Over-nutrition due to excess micronutrients is uncommon.

11-6 How is nutritional status determined?

Nutritional status is an assessment of whether an individual is receiving the correct amount of a well-balanced diet. The following are used when assessing the nutrition status of individuals or populations:

When interpreted together, these factors indicate whether a person is well nourished or malnourished. Comparing changes over time is also helpful.

11-7 How is nutritional status assessed using body measurements in adults?

To calculate BMI take a person’s weight (in kg), divide it by their height (in m) and divide it by their height (in m) again (i.e weight/height2). The answer to this calculation will place a person in a specific weight category for the BMI. The practical drawback of using BMI is that accurate weight and height is needed plus a calculator.

Table 11-1: Adult weight categories according to BMI

Body Mass Index (BMI) Weight category
Less than 18.5 Underweight
18.5 – 24.9 Healthy weight
25 - 29.9 Overweight
Over 30 Obese

Table 11-2: Adult weight categories according to upper-arm circumference

Adult mid-upper arm circumference Weight category
Less than 23 cm Underweight
23 – 33 cm Healthy weight
More than 33 cm Overweight
Note
Measuring the mid-upper arm circumference is useful to determine undernutrition in people who cannot be weighed (e.g. bedbound). Colour codes arm bands are available to screen both adults and children for undernutrition.

Table 11-3: Adult waist circumference and risk of chronic lifestyle disease.

Adult mid-upper arm circumference Weight category
Less than 23 cm Underweight
23 – 33 cm Healthy weight
More than 33 cm Overweight
Note
Waist circumference is a good indicator of the amount of fat within the abdomen and is a better predictor of risk for chronic diseases of lifestyle (diabetes, heart disease, high blood pressure) than the BMI.

The body mass index is used to screen for overweight and underweight in adults.

11-8 How is nutritional status assessed using body measurements in children?

The best way to assess a child’s nutritional status is by looking at their growth over time in comparison to their expected growth curve. The World Health Organisation (WHO) growth charts are currently used in South Africa and can be found in each child’s Road to Heath booklet. There are growth charts of weight for age, height (length) for age and weight for height. Plotting each value tells something about the child’s nutritional status and growth. Weight is the most common measurement that is plotted on growth charts.

11-9 How can weight be used to assess growth in children?

Plotting the child’s weight on a growth chart shows:

11-10 How is weight compared with other children of the same age?

Growth charts have 5 curves (lines), a median, and 2 “z score” lines on either side of the median that show the range of expected values. When weight is plotted on a growth chart:

Z scores are used to identify children with a weight above or below the normal range for age.

In a similar way height for age and weight for height can also be compared to other children.

Note
+2 and -2 z scores are equivalent to +2 and -2 standard deviations from the mean and are very similar to the 97th and 3rd centiles.

11-11 What does it mean if a child’s weight is more than 2 z scores outside the median?

Children with weights outside these lines (above 2+ or below -2) are considered at risk of malnutrition. The risk is highest if the weight falls outside the +3 or -3 z score lines. If a child’s weight is outside the average range of 2+ to -2, it does not necessarily mean that the child has a nutritional problem. Some children, particularly if they were low birth weight, may always remain smaller than other children even if their nutrition is normal. Therefore it is important to look for other signs of undernutrition or health problems, and to follow the child up. The trend over time in the weight is more important than the weight at a single point. If the weight is dropping off, the child should have a dietary assessment and should also be checked for diseases such as TB.

Note
99% of children will have size measurements between the +3 and -3 z lines

11-12 How is undernutrition and over-nutrition of macronutrients in children classified?

Undernutrition of macronutrients in a child can be classified as:

Over-nutrition of macronutrients in a child can be classified as:

A child’s mid-upper arm circumference can also be used to classify malnutrition:

Children with a weight for height below the -3 z line are severely wasted while those above the +3 z line are obese.

11-13 How common is stunting in South Africa?

In South Africa, stunting has remained between 20-30% over the past 20 years for children under 5 years of age. Stunting is more common than underweight or wasting in low- and middle-income countries.

In South Africa 20-30% of young children are stunted.

Note
A 2014 national survey found that 26.4% of children under 3 years of age were stunted.

11-14 What are the causes of stunting in children?

The causes of stunting are:

11-15 What are the consequences of stunting in children?

When children are stunted, they are at risk of:

Stunting contributes to the cycle of poverty.

11-16 How common is over-nutrition in South Africa?

Overnutrition of macronutrients (eating too much), resulting in excessive energy intake, is a significant and growing problem in South Africa:

Obesity is very common in both children and adults in South Africa.

11-17 What are the consequences of over-nutrition?

In both children and adults being overweight or obese can increase the risk of developing many chronic conditions such as hypertension, diabetes and heart disease. Being overweight also worsens arthritis and can impair physical mobility and respiratory function.

Over-nutrition increases the risk of many chronic conditions such as hypertension, diabetes and heart disease.

11-18 How important is micronutrient undernutrition in South Africa?

Recognising micronutrient deficiency is difficult because the effects often go unnoticed. For this reason, micronutrient undernutrition is often referred to as hidden hunger. The micronutrients about which we have good information are vitamin A and iron:

Other micronutrient deficiencies include vitamin B and D, zinc and iodine.

Iron and vitamin A deficiency are common in South Africa.

11-19 What are the causes of micronutrient deficiencies in South Africa?

Micronutrient deficiencies can occur as a result of:

Vitamin A is present in yellow vegetables like carrots and pumpkin as well as green leafy vegetable like spinach. Iron is present in meat, eggs and green vegetables.

11-20 What are the dangers of vitamin A deficiency?

When children lack vitamin A it causes:

11-21 What are the dangers of iron deficiency?

When children lack iron it causes:

Iron deficiency is an important cause of anaemia.

11-22 At what stages of life are nutritional problems found?

Nutritional problems can occur throughout the lifespan but are more common in:

11-23 What are the common nutritional problems in pregnancy?

Common problems in pregnancy are:

11-24 Why is nutrition important in the first thousand days of life?

The first thousand days of an individual’s life, from conception to the age of 2 years, is critical in determining long term growth, health and welfare. Once this window of opportunity has passed it is very difficult for nutritional interventions to make a lasting positive impact on a child’s health.

Childhood is also an important life stage to shape a child’s habits. If a child is learning to enjoy a variety of different healthy foods during this time it is likely that they will wish to eat these foods when they are older. On the other hand overweight children often grow into overweight adults.

Good nutrition during the first thousand days of life is critically important to growth and development.

11-25 Which common adult diseases are associated with undernutrition?

Undernutrition is a risk factor for infections such as TB, but an infection can in turn also lead to undernutrition. Therefore undernutrition and infection exist in a vicious cycle. Good nutrition in TB and HIV infected adults can improve health and quality of life.

Optimal nutrition also plays an important role in the control of many chronic non-communicable diseases. Achieving and maintaining a healthy body weight should be an important goal for all people, especially those living with non-communicable diseases.

Undernutrition and infection exist in a vicious cycle.

11-26 Why is undernutrition important in the elderly?

Because the elderly are frequently undernourished as a result of:

11-27 What is household food insecurity and what is hunger?

Household food insecurity is defined as one or more of the following within the previous 30 days:

More than half of South African households are food insecure.

Hunger is defined as 5 or more positive responses to the above questions. Just over 1 in 4 South African households experience hunger.

Over 25% of South African households experience hunger.

11-28 What are the main causes of undernutrition in South Africa?

The main causes of undernutrition are:

Many of these problems may also result in over-nutrition from bad choices about what the food budget will be spent on. For many people, perceptions about desirable foods are shaped by the marketing of junk food.

Poverty is the main cause of undernutrition in South Africa.

11-29 What is being done to address undernutrition in South Africa?

There are various policies and programmes in place to address nutritional problems. They have the potential to make a significant difference to the nutritional status of South Africans if well implemented with adequate coverage. Strategies include:

11-30 What is the fortification of staple foods?

Fortification of staple foods means adding micronutrients to accessible, affordable foods regularly consumed by a significant proportion of the population at risk of undernutrition. For example:

Fortification benefits the whole population by adding micronutrients to basic foods.

11-31 What is micronutrient supplementation?

Micronutrient supplementation is a short-term solution to address micronutrient deficiencies by providing drops, syrups or tablets to specific vulnerable groups. For example:

Micronutrient supplementation is only given to groups at risk of deficiency.

11-32 What is the National School Nutrition Programme?

In geographic areas with high poverty levels, public primary schools where most of the learners are identified to be in need have a school nutrition programme provided by the Department of Education. The main goal is to improve the learning capacity of students by improving their nutrition with a school feeding scheme.

11-33 What is the Nutritional Therapeutic Programme?

The Nutritional Therapeutic Programme aims to identify and support people who are undernourished or at risk of becoming undernourished, such as:

People meeting the programme’s entry criteria receive products such as enriched porridge, enriched energy drinks, or an enriched spread such as peanut butter for 6 months. Challenges with this programme include:

These obstacles can render the programme ineffective in addressing undernutrition.

11-34 What are food parcels and who gets them?

A temporary support system for individuals or households who are food insecure is the provision of food parcels. These parcels most often consist of staple foods (such as maize flour, samp and rice), non-perishable protein sources (such as tinned fish, peanut butter and beans) and other basic food items (such as oil, tea and sugar).

People may be identified through contact with the healthcare system or by non-governmental organisations that work in the community. Funding for parcels may be from Department of Social Development or from non-governmental organisations. The criteria for receiving a food parcel differ between organisations.

11-35 What other resources are available for individuals and households facing hunger?

In urban areas, there are often many different community-based projects aimed at alleviating hunger for vulnerable people. These are most often organised by non-governmental or faith-based organisations. Economic meals are prepared and distributed to people who are identified as being food insecure (food kitchens).

Most nutrition services for older people are provided by non-governmental organisations that aim to support older persons in the community. Some of these programmes are subsidised by the Department of Health or the Department of Social Development, and include home-based care and community-based senior clubs. Services provided at senior centres usually include healthcare, counselling and recreational or empowerment activities in addition to the provision of meals.

Case study 1

While assessing the nutritional status of a woman with diabetes her weight is recorded as 90 kg and her height as 1.69 m. Her mid-upper arm circumference and waist circumference are also measured.

1. What is her body mass index and is it normal?

Her BMI of weight (in kg) divided twice by her height (in cm) is 31.5. This indicates that she is obese as the normal range for BMI in adults is 18.5 to 24.9.

2. What is the usefulness of measuring her mid-upper arm circumference?

It is a simple and easy screen for underweight or overweight. Her measurement is above the normal range of 23 to 33 cm.

3. Why is waist circumference helpful?

A high waist circumference is a good predictor of chronic illness. Her measurement is 103 and that places her at severe risk.

4. What is your assessment of this woman’s nutritional status?

She is obese and a diabetic. It is important that she is given good nutritional advice and encouraged and supported to lose weight. This will not only improve her diabetic control but also lower her risk of hypertension and heart disease.

Case study 2

You see a 5-month-old child with a cough at the local clinic. He had a normal weight at birth but his weight-for-age is now below the -2 z-score. He is no longer breastfed. The mother says they cannot afford milk formula and she often goes to bed hungry. She has not gone to the clinic before as she is embarrassed that she has no income.

1. What is the meaning of a weight-for-age below the -2 z score?

It means the child’s weight is below the normal range for children of 5 months of age. This indicates that the child is underweight and probably undernourished.

2. How could you tell whether this child is also stunted?

If he was stunted his length-for-age would also be below the -2 z score. Stunting indicates chronic undernutrition. With a recent illness such as diarrhoea he may not be stunted but have a low weight-for-length suggesting sudden weight loss.

3. What is the probable cause of his low weight-for-age?

Most likely a poor diet. He is not being breastfed and the mother cannot afford formula. It is possible that this child might also have an illness such as TB and therefore needs to carefully examined. There is likely to be social problems as the mother has not attended clinic. If the child was exclusively breastfed it would have provided all the macronutrients and micronutrient for normal growth and development.

4. How could you help this mother improve the child’s diet?

She must be encouraged to attend clinic regularly and be educated about the nutritional needs of a young child. She probably needs food parcels and a child grant to help both her and her child have a good diet. Follow up is important to make sure that the child gains weight and grows normally.

Case study 3

A parent asks about the national policy that provides children from 6 months to 5 years of age with a dose of vitamin A twice a year. The family wants to know if this is needed even in well-nourished children.

1. Should vitamin A supplementation be given to all children?

Yes. Vitamin A deficiency is common in South Africa.

2. What foods are rich in vitamin A?

Vitamin A is present in yellow vegetables like carrots and pumpkin as well as green leafy vegetable like spinach.

3. What problems are caused by vitamin A deficiency?

Clinical problems include poor appetite, poor growth, increased risk of infections and dry eyes.

4. Is vitamin A deficiency always caused by a poor diet?

No. It can also be caused by malabsorption such as environmental enteropathy.