Wednesday August 1, 2012
The wonders of protein
By Prof Dr POH BEE KOON
Children need various nutrients for their growth and development. Find out how proteins, an essential nutrient, can do the trick, and learn how to incorporate protein-rich foods into your child’s diet.
YOU may have heard this many times before; protein is an essential nutrient and is beneficial to your child’s health. But do you know how it helps in growth and development?
Proteins are a remarkably versatile nutrient. They help your child’s muscles to contract, his blood to clot and his eyes to see. They keep him active by facilitating chemical reactions through enzymes and defending against infections. Without them, your child’s bones, skin and hair would have no structure.
It is no wonder that the term “protein”, which is derived from the Greek word “protos”, means “of prime importance”.
Proteins are made up of long chains of amino acids, the building blocks of protein. The human body contains an estimated 100,000 different kinds of protein.
The role of protein
Whenever your child’s body is growing, repairing (healing) or replacing tissue, proteins are at work. They play important roles in his body to promote health and prevent disease.
Apart from forming the building blocks of muscles, blood and skin, proteins are also needed to:
> Replace dead or damaged cells and tissues.
> Regulate body processes (some, but not all, hormones are proteins).
> Maintain the volume and composition of body fluids.
> Transport substances like lipids, vitamins, minerals and oxygen around the body.
> Defend the body against diseases through antibodies and strengthen the body’s immune system.
When children are deprived of protein, energy, or both, the result is protein-energy malnutrition (PEM). The most evident result of protein deficiency is the wasting of muscle tissue and weight loss.
A lowering of serum protein levels and hormonal changes may result in oedema (an excessive build-up of fluid in the body’s tissues) and the reduced production of antibodies makes the affected child susceptible to infection.
Although PEM in Malaysia is rare, it is something that you should take note of.
On the other hand, with an abundance of protein-rich foods in Malaysia, there is also the problem of over-consumption of protein. Research has suggested that high-protein diets offer no benefits and may pose health risks like heart disease, osteoporosis, obesity and kidney stones.
For example, excess protein will be converted to body fat, and excessive protein may also overwork the kidneys.
Excessive protein intake can also result in high blood cholesterol as most protein-rich foods are also high in saturated fat – fatty cuts of beef, lamb, sausages, pork, salami, duck and organ meats like kidney and liver.
Sources of protein
Proteins in our diet are derived from two main sources, namely animal protein (such as milk, egg, meat and fish) and plant proteins (such as cereals, nuts, beans and soy products).
Animal proteins are more “biologically complete” than plant proteins because animal proteins contain all the essential amino acids that is needed by the body.
Although plant proteins are incomplete proteins, they are good substitutes for meats or other animal proteins.
In addition, if two plant proteins such as legumes and grains or legumes and nuts/ seeds are mixed together, they will complement each other and provide all the necessary essential amino acids to an individual.
In view of the importance of proteins for your child, as well as the problems that can occur from deficient or excessive intake of protein, the Malaysian Dietary Guidelines has recommended that you:
> Feed your child fish more frequently, daily if possible. To achieve this, get your child to eat a serving of fish daily. Shellfish should be consumed less frequently than fish.
> Increase your child’s intake of milk and dairy products. Milk is not only a valuable source of protein but also a rich source of calcium and vitamins.
A glass (250 ml) of fresh whole milk contains about 8.5g of protein. Add milk that is low in sugar to your child’s oatmeal and cereals. Yogurt and cheese are also good sources of dairy products.
> Feed your child meat, poultry and eggs moderately. Choose a variety of meats and use different methods to cook these dishes. Get your child to consume eggs in moderate amounts, up to an average of one a day (whole or in dishes). Avoid giving egg white to your child who is one year old or younger.
> Adopt healthier cooking methods for fish, meat, poultry and eggs. Recommended cooking methods include steaming, stewing, boiling, poaching, grilling and roasting. Use herbs, spices, and lime or lemon to season and flavour these dishes instead of salt or rich sauces.
> Choose meat and poultry that are low in fat and cholesterol. Minimise saturated fat by choosing lean cuts of meat and poultry. Remove chicken skin and trim visible meat fats before cooking.
> Feed your child legumes daily and include nuts and seeds in his weekly diet. Legumes like peas, lentils, beans, chickpeas, soybeans and peanuts have large amounts of proteins in their seeds. Choose a variety of legumes and their products like tempeh and tofu to prepare meals. Add legumes to your child’s soups and dishes. Serve nuts as snacks or in main dishes, such as in stir-fry vegetables.
How much do they need?
According to the Recommended Nutrient Intake (RNI) for Malaysia, the recommended level of protein intake for children aged between one and six years is 17g to 23g per day. Children between the ages of seven and 12 years need approximately 32g to 46g of protein a day.
Below are examples of how you can get your children aged between one and six years old to meet their recommended protein intake in their everyday meals.
> For breakfast, serve one scrambled egg on toasted bread.
> For lunch, serve ½ a piece of tenggiri fish (Spanish mackerel) with rice and mix vegetables.
> For tea or snack time, serve one cup of milk with some crackers.
> For dinner, serve ½ a chicken drumstick with braised noodles and mix vegetables.
You can mix and match or substitute the above dishes with other protein food sources like tofu, yogurt, cheese, beef, soya milk, chickpeas or lentils (dhal).
Children aged seven years and older can have twice the above amounts in a day; for example, he or she can have one whole piece of tenggiri fish and one whole chicken drumstick. You can also give your child one cup of milk in the morning and another cup during tea time or at night.
Balance is key
Although proteins are very important in your child’s diet, it must be remembered that a balance of essential nutrients (carbohydrates, fats, vitamins, minerals and proteins) are vital for everyone, especially growing children.
To build strength, your child’s muscle cells need physical activity and all the other nutrients. By over-valuing proteins, you might erroneously exclude all the other equally important foods and nutrients.
Too much or too little of anything is bad. Practise balance, moderation and variety in preparing your child’s meals to ensure your child’s proper development and to prevent diseases now and throughout his adult years.
Prof Dr Poh Bee Koon is a nutritionist. This article is courtesy of Positive Parenting Programme by the Malaysian Paediatric Association and supported by an educational grant from Wyeth Malaysia Sdn Bhd. The opinions expressed in the article are the view of the author. For more information, please visit mypositiveparenting.org.