Nutrition in Children

• Why is nutrition so important in children?
• Adolesence
• Long term importance of nutrition in children
• Essential nutrient requirements
• Glycaemic index and glycaemic load
• Specific dietary requirements
• Ways to maintain good nutrition in children
• Physical activity
• Strategies to make nutrition more enjoyable for children

The nutritional needs of children and adolescents are different from those of adults because children are growing and developing. Children need a wide range of nutritious foods, with high intake of important minerals and vitamins such as protein and calcium. If your child’s intake of good food is poor, they can fail to gain or lose weight. This may be followed by failure to grow taller.

Why is nutrition so important in children?

Infants and children are more likely to suffer from poor nutrition than compared to adults. There are a number of reasons for this.

• Low Nutritional Stores: Newborn infants have low stores of fat and protein. The smaller your child, the less reserves of energy they have. This means that they can only cope with starvation for shortened periods of time.
• High Nutritional Demands For Growth: The amount of nutrition children require is greatest during infancy. This is because of their rapid growth during this period. When your child is 4 months old, 30% of their nutritional intake is used for growth. By the age of 1 year, this falls to 5%.
• Rapid Development in the Nervous System: Your child’s brain grows rapidly during the last four months of pregnancy and also during the first two years of life. The connections between the nerve cells in the brain are being formed during this time. Good nutrition is important to ensure that this occurs properly.
• Illness: Your child’s nutrition may be compromised following an episode of illness or surgery. The body’s energy requirements are increased, thus intake of food and nutrients should be increased.

Adolescence (11-19 years)

There is an important growth period during adolescence, in which your child will experience a marked increase in the rate of weight gain and height. The growth spurt in children begins on average at 10 to 11 years in girls and at 12 to 13 years in boys, although there is wide variation. During the adolescent growth spurt boys gain about 20 centimetres in height and 20 kilograms in weight. Girls gain around 16 centimetres and 16 kilograms. The maximum weight gain tends to occur about three months after that for height. Adolescence is a very important period for gaining calcium and for building up strong bones, especially in girls. The majority of bone formation occurs during adolescence, thus it is important to ensure adequate calcium intake. Data from studies suggest that for most healthy adolescents the maximal calcium balance is achieved with intakes of between 1200 – 1500 milligrams a day.

Long term importance of nutrition in children

Height
Growth and nutrition are closely related to each other. The average height of a population reflects its nutritional status. In the developed world, the population has gotten taller in height. In undeveloped countries, there are shorter children, due to lack of nutrition and energy intake for adequate growth.

Disease in adult life
There is evidence suggesting that undernutrition whilst the mother is carrying her baby can result in growth restriction. This is associated with an increased incidence of diseases such as high blood pressure, heart disease, stroke, type 2 diabetes mellitus, and lung disease in later life.

Obesity
Australia is involved in a worldwide obesity epidemic, affecting children of all ages. Overweight children are likely to become obese adults, and an overweight child with an obese parent has more than a 70 per cent chance of being obese in young adulthood. Obesity occurs when the total amount of calories that are consumed exceed the total that children use up through metabolic processes (such as playing, sweating and breathing). A gross measure of the degree of obesity can be determined by the Body Mass Index (BMI). This is determined by:

BMI = body weight (in kg) / stature (height, in meters) squared

While in adults, the BMI cut-offs internationally accepted as definitions of overweight and obesity (25 kg/m² and 30 kg/m²) are based on increased risks of morbidity and mortality, no such outcome based definition exists for children. Definitions for children and adolescents have generally been based on data sets collected from other groups of children of corresponding ages.
The use of BMI is less appropriate for infants, children and adolescents because of different rates of gain in weight and height during development. It is common for children to gain weight quickly and their BMI may increase rapidly during puberty. For this reason, it is important to compare BMI calculations against age and gender percentile charts. For example, if a child has a BMI in the 65th percentile, 65% of kids of the same gender and age have a lower BMI. A child above the 95th percentile is considered overweight because 95% of the population has a BMI less than he or she does. A child whose BMI is at the 50th percentile is close to the average of the population. A child below the 5th percentile is considered underweight because 95% of the population has a higher BMI. Children can also have a high BMI because he or she has a large frame or increased muscle mass, not excess fat.

It is also important to look at the BMI values over a period of time, as a trend instead of focusing on individual measurements. Single values, taken out of context, might give you the wrong impression of your child’s growth. Prevention is better than treatment.
Once your child is overweight or obese, it is more difficult to loose weight. There are undesirable effects on your child’s body both physically and mentally. Obese children are more likely to develop high sugar levels and high cholesterol levels. This can lead to diseases such as diabetes and blood vessel and heart problems. There may also be effects on your child’s self esteem and body image – obese children may be stereotyped and called names or bullied at school.

Essential nutrient requirements

Energy
Marked variability exists in the energy requirements of children because of different growth rates and physical activity levels. Total energy requirement recommendations are based upon how much energy your child uses, plus 3 to 4 percent to cover the energy needed for growth. The recommended composition of dietary energy intake consists of reduced consumption of cholesterol, total fats, (especially, saturated fat) and an appropriate weight and height for your child’s age.

Protein
Protein is important in children for growth, tissue repair and to make essential hormones and enzymes in the body. When energy intake is insufficient, protein intake must be raised. This is because ingested proteins can be directed towards pathways of energy synthesis. For children, the recommended dietary allowance for protein is about 1g/kg body weight per day. Foods such as milk and cheese are excellent sources of calcium and protein for children.

Fats
Fats are a concentrated and rich source of energy. In children, it is recommended that fat intake total no more than 30% of calories. Saturated fat and trans-fat should be limited to less than 10% of calories, and polyunsaturated fats to less than 10% of calories. The rest of the fat intake should consist of monounsaturated fats.

• Trans fats: These fats are artificially created. This solidifies the oil and limits the body’s ability to regulate it’s cholesterol. These fats are considered to be harmful to your child’s health. Trans fats are found mainly in deep-fried fast foods and processed foods made with margarine.
• Saturated fats: This type of fat is found in foods such as butter and beef fat.
• Polyunsaturated fats: This group includes omega 3 and 6 essential fatty acids (EFA’s).There are high levels found in fish oil, vegetable and nut oils.
• Monounsaturated fatty acids: This is found mainly in chicken fat and vegetable oils such as olive, canola and peanut oil.

Carbohydrates
Carbohydrate recommendations for young children are similar to those recommended for adults (around 55% of total energy intake). To meet their carbohydrate needs, active children should enjoy a diet high in carbohydrate rich foods as well as nutritious high carbohydrate snacks between meals.

Water
Maintaining adequate hydration is essential for the prevention of conditions such as dehydration and heat stress (when heat is absorbed from the environment faster than the body can get rid of it.). Your child’s body has less developed mechanisms to regulate body temperature. They produce more body heat per kilogram of body weight than adults, but their ability to transfer heat through their blood, to the skin is diminished. When exposed to high temperatures, children may absorb more heat than adults, because they have a high ratio of skin exposed to the sun. This shows the importance of regular fluid intake in your child.
It is recommended that active children drink 150 – 200 mLs of fluid 45 minutes prior to exercise, plus an additional 75-100 mL every 20 minutes during exercise. Water is recommended as the best choice of fluid.

Glycaemic index and glycaemic load

As discussed above, carbohydrates should make up at least 55% of total daily calories. In more recent times, the quality and also quantity of these carbohydrates has been shown to be important in blood sugar control. Even though different foods may contain the same amounts of carbohydrates, the effects on blood sugar control may be totally different. This has lead to the development of measures such as the glycemic index (GI) and glycemic load (GL) of a food product.
As parents, we want to provide our children with the best possible foods for maintaining a healthy diet and for control of rises in their blood sugar levels. Low GI and GL foods have been shown to be associated with health advantages such as a decrease in blood sugar levels. This is particularly important if your child suffers from diabetes, to prevent hyperglycemic (elevated blood sugar levels which can cause symptoms such as dry mouth, an increase in going to the toilet to pass urine and nausea) episodes. In the longer term, control of blood sugar levels is also important to prevent diseases such as heart disease, major vessel disease and obesity. The Glycemic Index (GI) is obtained by measuring the effect that a carbohydrate containing food has on blood sugar levels, compared to the effect of the same amount of pure sugar, on blood sugar levels.
The following ranges are usually applied to determine the GI of a particular food:

• Low GI – 55 or less.
• Medium GI – 56 to 69.
• High GI – 70 or more.

Foods with a low GI (less than 55) means that they cause a slower and lower rise in blood sugar levels. These include: breads such as mixed-grain and oat breads, barley, pasta, noodles, beans, sweet potatoes, green peas and milk.
Foods with a high GI (greater than 70) means that they cause a faster and higher rise in blood sugar levels. High GI foods include: white bread, steamed white rice, chips and coffee.
By aiming to provide your children with low GI foods, this will help bring down the average GI of their meal and prevent sudden increases in blood sugar levels. Foods with a low GI are also often more healthy and nutritious. These foods allow blood sugar levels to be sustained at a lower level over a longer period of time. After we consume carbohydrate containing foods, the body signals the pancreas to secrete a hormone called insulin to break it down. Insulin acts to lower the body’s sugar levels. When the blood sugar levels decrease to a particular level, the brain is sent a signal and we become hungry again.
By providing children with low GI foods, they are more likely to be satisfied and feel full for longer periods of time. This helps in maintenance of a healthy weight and avoiding the development of diseases such as high cholesterol, increased blood pressure levels and heart disease. The glycemic load (GL) of a food ranks the effect of a specific serving size of that food on the blood sugar levels.

GL Ranges
The following ranges are usually applied to determine the GL of a particular food:

• Low GL – 10 or less.
• Medium GL – 11 to 19.
• High GL – 20 or more.

The following values are applied to define the GL per day:

• Low GL – less than 80.
• High GL – more than 120.

Foods with a low GL means that they cause a more steady and lower rise in blood sugar levels. These include: many fruits and vegetables. Foods with a high GL means that they cause a faster and higher rise in blood sugar levels.
High GL foods include those such as white rice and refined snack foods such as chips and sweetened drinks. Generally, foods with a low fibre content and high carbohydrate levels have high GI and GL values, whereas those with high fibre contents have lower GLs.
Clinical studies have also shown that the dietary GL is linked to risk factors for heart and major vessel disease, diabetes and obesity. For more information on the glycemic index and glycemic load, and tips on how to provide your children with low GI foods, visit these pages on Glycemic Index (GI) and Glycemic Load (GL).
 

Specific dietary requirements for infants, children and adolescents

Infants
In infants up to the age of 6 months, breast milk universally provides the ideal food, containing all nutrients your baby will need to grow and develop. The breast fed infant typically nurses every two to three hours while awake, or eight to twelve times a day. It is recommended that solids should not be started before the age of four months, but not be delayed much beyond the age of six months.
Modern infant formulas provide a suitable form of nutrition when an infant does not have access to breast milk. Traditionally formulas are based on cow’s milk, with varying proportions of casein and whey proteins. There are also formulas based on soy or goat’s milk and lactose-free formulas for infants who cannot tolerate cow’s milk or lactose.
The frequency of feeding is highly variable in a formula fed infant because of differences in the time the stomach takes to empty. Feeds should be guided by the infant’s demand: most infants will demand six to nine feeds a day. They will slowly increase their intake from 30 to 90 ml every three to four hours by the end of the first week of life. Overall, the formula fed infant consumes an average of 100-110kcal/kg per day during the first year of life.
The introduction of solid foods should ideally start with iron-enriched infant cereals at about six months. Gradual introduction of various vegetables, fruits, meats, poultry and fish can then occur. Ensuring that the foods introduced are high in nutrients and providing a good variety of texture is also important.
By twelve months of age, an infant should preferably be consuming a wide variety of family foods and progressed from pureed foods to foods that are chopped into small pieces. Vitamin and mineral supplements are not usually needed for healthy, full-term infants or children. However in lower socioeconomic areas, there may be deficiencies such as water without fluoride and poor intake of foods rich in vitamins and minerals, which means that further supplementation will be required.

Children
From the age of twelve months onwards, children grow at a much slower rate than compared to their infancy phase. While growth slows somewhat, nutrition remains a top priority. Young children are also discovering their independence and may test their choice in food selection, leading to reduced interest in eating. This can give the impression that they are poor or fussy eaters. Generally, this does not compromise normal growth, but if additional constraints are placed on the diet, such as restricting certain types of foods (including cholesterol rich foods), nutritional deficiencies can occur.
Depending on their age, size, and activity level, young children need about 1,000-1,400 calories a day. According to the healthy food pyramid, this can be achieved by:

• six servings of from the breads/cereals/rice/pasta group (1 serving = 1 slice of bread, 1 cup of cereal, 1/2 cup of cooked cereal, rice, or pasta).
• five servings from the fruit and vegetables group (1 serving = 1 cup of raw leafy vegetables, 1/2 cup of other vegetables cooked or raw, 3/4 cup of vegetable/fruit juice, 1 medium apple, banana, orange, pear).
• two servings from the milk/yoghurt/cheeses group (1 serving =1 cup of milk or yogurt, or 2 slices (40g) of cheese).
• two servings from the meat and beans group. (1 serving = 55-85g of cooked lean meat, poultry, or fish, 1/2 cup of cooked dry beans).

Milk
Milk is an important part of a child’s diet as it is a good source of calcium and vitamin D, which helps build strong bones. Young children should be getting at least 500 milligrams of calcium a day. This is easily provided by two servings of dairy foods every day.
Iron
After 12 months of age, children are at increased risk for iron deficiency because their intake of iron-fortified formula or breast milk is greatly reduced. Young children should be getting about seven milligrams of iron each day.
It is important to ensure that your child is receiving enough iron, as low iron levels can affect a child’s growth and may lead to learning or behavioural difficulties. Iron deficiency anaemia – a condition where there is a decreased number of red blood cells in the body can also develop. Red blood cells help carry oxygen throughout the body and depend on iron to be produced. If there are not enough red blood cells, tissues and organs in the body do not receive enough oxygen and fail to function as well as they should.
It is very important to realise that cow’s milk is low in iron. Drinking a lot of cow’s milk (more than three cups of milk) also put your child at risk of developing iron deficiency. Children can also be filled with milk and less likely to eat iron rich foods. In some cases, milk can decrease the absorption of iron and irritate the lining of the gut (intestine). This may result in small amounts of bleeding and loss of iron through the stools.
To help avoid iron deficiency occurring, you should try and limit your child’s milk intake to less than three cups a day and increase iron rich foods such as green leafy vegetables and lean meats.

Adolescents
Nutritional needs during adolescence are influenced primarily by the commencement of puberty with the onset of growth spurts and changes in body composition and organ systems. There is an increase for energy and almost every nutrient. Growth during adolescence is accompanied by an increased proportion of body fat for girls and an increased proportion of lean body mass and blood volume in boys.
The most common nutrient and vitamin deficiencies involve iron and calcium. Iron deficiency is the most prevalent dietary deficiency in:

• Older adolescent girls
• Pregnant teenagers
• Vegetarian teenagers
• Lower socioeconomic groups
• Athletes who have increased iron losses.

Rapid growth in adolescence leads to increased vulnerability to iron deficiency. Increases in lean body mass, blood volume, and red cell mass raise iron needs for the body. It is also more common in teenage girls due to iron loss from menstruation and decreased dietary intake. We should therefore encourage adolescents to eat iron fortified breads and cereals and other iron rich foods such as lean meat, dried fruits, nuts and green leafy vegetables. It is recommended that pregnant teenagers take iron supplements.
Calcium intake is particularly important for women. Intake tends to be low in adolescent diets due to factors such as drinking less milk in favour of carbonated drinks and avoiding dairy products due to concerns about weight gain. Bone mass achieved during adolescence is important to decrease the chance of osteoporosis in later life. We should encourage at least two to three serves of milks, yoghurts and cheeses each day.
Adolescence is a time of independence and new body images, and can be a transitional stage when food habits change and adolescents are seeking more control over their food intake. Common eating behaviours during this time include eating away from home, increased intake of fast foods, snacking and skipping meals. Adolescents have increased energy requirements, which require high calorie snacks. However, commonly chosen snack foods are typically high in fats, sugars and salts. We should aim to increase nutritious snacking through promoting healthy snacks such as increased fruit and vegetables.

Ways to maintain good nutrition in children

The National Health and Medical Research Council (NHMRC) have released a set of recommended dietary guidelines for Australian children. These guidelines apply to the general population of healthy children from birth to eighteen years.

1. Encourage and support breastfeeding:
There is no doubt that breast milk is the best diet for babies. In developing countries where there is a high incidence of infection and contamination within the environment, breast feeding improves survival. Breast feeding also helps promote an intimate relationship between the mother and baby. It may also provide an advantage in long term development of the brain and it’s related structures, especially in pre-term infants. The most likely nutrients in breast milk that are responsible for this are long chain polyunsaturated fatty acids.

2. Children and adolescents need sufficient nutritious foods to grow and develop normally:

• Growth (weights and heights) should be checked on a regular basis for young children.
• Physical activity is important for all children and adolescents.

3. Enjoy a wide variety of nutritious foods:
Children and adolescents should be encouraged to:

• Eat plenty of vegetables, legumes and fruits
• Eat plenty of cereals (including breads, rice, pasta and noodles), preferably wholegrain
• Include lean meat, fish, poultry and/or alternatives
• Include milks, yoghurts, cheese and/or alternatives

Reduced-fat milks are not suitable for young children under 2 years, because of their high energy needs, but reduced-fat varieties should be encouraged for older children and adolescents.

• Choose water as a drink
• Alcohol is not recommended for children

Care should be taken to:

• Limit saturated fat and moderate total fat intake
• Low-fat diets are not suitable for infants
• Choose foods low in salt
• Consume only moderate amounts of sugars and foods containing added sugars

4. Care for your child’s food: prepare and store it safely:
This is important to ensure decreased spread of infections within children.

Physical activity

Physical activity is an important part of everyday life for children and adolescents. It plays an important part in physical growth and the development of a range of skills. It also provides a mechanism for balancing energy intake and energy output and decreases the incidence of obesity. In girls, physical activity is related to bone density in adulthood. The physical activity guidelines for Australians make the following recommendations:

• Children should be active every day in as many ways as possible.
• Children should achieve at least 30 minutes of moderate-intensity activity on most, preferably all, days.
• If possible, children should enjoy some regular, vigorous exercise for extra health and fitness.

Strategies to make nutrition more enjoyable for children

Snacks and lunchbox ideas:
As part of a healthy diet children should eat 3 main meals and 2-3 snacks a day. In children, snacks are an important part of daily food intake. They should be tasty, easy to prepare and full of nutrition. Ideal snacks include:

• Slices of fruit bread / buns.
• Slices of fruits / vegetables.
• Small handfuls of plain / wholemeal crackers with cheese, fruits or vegetables.
• Small cup of popcorn / dried fruits.
• Tub of low fat yoghurt.
• Homemade / low fat muffins

Drinks in school
For the lunchbox
Fill with a variety of healthy foods. Include plenty of fresh fruit, vegetables and bread or crackers. Incorporate low fat protein food such as meats, fish, dairy products or eggs. Different breads and rolls such as wholemeal, multigrain, white hi-fibre, bagels, pocket, focaccia, turkish and flat breads can be used for variety. Margarine spreads should be used sparingly. Sandwiches can be cut into different sizes and shapes for novelty. There are many fillings, which can be tried, depending on the child’s taste – lean beef or chicken with lettuce, tomatoes, avocados, etc.
It is important to involve the child in choosing their own lunch from a range of healthy options. Children who are involved in their own food choices may be more likely to adhere to good eating habits.

References

1. Butte N. Dietary Energy Requirements in Adolescents. UpToDate [journal online] 2006 [cited 28th June 2006] Available from URL: http://www.uptodate.com
2. Dietary Guidelines Advisory Committee. Dietary guidelines: build a healthy base [online]. 2000 [cited 28th June 2006] Available from URL: http://www.health.gov/DIETARYGUIDELINES/dga2000/document/build.htm
3. Dietary Guidelines for Children and Adolescents in Australia [online]. 2003 [cited 8th May 2006]. Available from URL: http://www.nhmrc.gov.au/publications/synopses/dietsyn.htm
4. Dwyer J. Harrisons Principles of Internal Medicine; Nutritional Requirements and Dietary Assessment. USA: The McGraw-Hill Companies; 2006
5. Lissauer T, Clayden G. Illustrated Textbook of Paediatrics. Spain; Mosby International Limited, 2003.
6. Margarey A, Daniels L, Boulton J. Prevalence of overweight and obesity in Australian children and adolescents: reassessment of 1985 and 1995 data against new standard international definitions. MJA 2001; 174: 561-564
7. NSW Health, Nutrition & Pain, Community Information Series, Hunter Integrated Pain Service; 2005
8. Phillips S, Motil K. Dietary History and recommended dietary intake in children. UpToDate [journal online] 2006 [cited 28th June 2006] Available from URL: http://www.uptodate.com
9. What are the major differences in dietary requirements for highly active compared with normally active children? [online]. 2000 [cited 8th May 2006]. Available from URL: http://www.mja.com.au/public/nutrition/question3.html

• Augustin L, Franceschi S, Jenkins D, et al. Glycemic index in chronic disease: a review, European Journal of Clinical Nutrition, 2002; 56: 1049-1071.