Why is nutrition special to you?

• You are not only maturing physically but also psychosocially and cognitively.
• You are always exposed to inadequate intake due to:
  • Irregular meals and snackings.
  • Skipping meals.
  • Eating away from home.
  • Following alternative dietary patterns.

• Therefore, you are likely to obtain less essential micronutrients such as iron, zinc, calcium, folate and iodine.

What causes deficiencies? Nutritional deficiencies in adolescents may be caused by:

• Inadequate intake.
• Poor absorption.
• Increased requirements and losses of nutrients.
• Poor utilization of nutrients.
• Infection.
• Poverty.
• Practising food taboos that could lead to inadequate intakes.

What are the common nutritional deficiencies in adolescents? Nutrients often deficient are:

• Iron.
• Zinc.
• Calcium.
• Folate.
• Iodine.

Iron

Role of iron

• It is important in energy metabolism.
• For males, iron is needed for building up muscle mass.
• For females, you need 10% more iron due to menstrual losses and normal need for linear growth.
• Due to differences in requirements, the recommendations are specified separately for boys and girls.
• The amount of dietary iron absorbed is mainly determined by the amount of iron stores in the body and by the properties of the diet in terms of iron content and bioavailability. See RNI for Malaysia 2005. (You require Adobe Acrobat Reader to view the following document).

Deficiency

• The consequences of iron deficiency are:
  • Impaired physical work.
  • Cognitive impairment.
  • Developmental delay.
  • Adverse pregnancy outcomes.

• Lack of iron is associated with Iron Deficiency Anaemia.
• Anaemia secondary to iron deficiency may impair the immune response and decrease resistance to infection. It also can affect your learning and work performance.

Sources

• There are two types of iron in foods i.e. haem iron and non-haem iron.
• Haem iron is derived primarily from the animal sources such as meats, poultry and fish.
• Non-haem iron is found in plant sources such as dark leafy vegetables, cereals and beans.
• Include iron rich foods as part of your healthy diet.

Zinc

Role of zinc

• Zinc is a trace element and known to be essential in metabolic activity as a component of key cell enzymes.
• Zinc also plays important role in the immune system, growth and sexual maturation.
• Zinc requirement is shown in the RNI for Malaysia 2005. (You require Adobe Acrobat Reader to view the following document).

Deficiency

• Zinc deficiency can occur through various mechanisms such as :
  • Inadequate intake.
  • Malabsorption.
  • Increased requirements and losses.
  • Impaired utilization.
• Zinc deficiency will affect the integrity of the immune system and may effect your physical growth including development of sex characteristics.

Sources

• Rich sources of dietary zinc include meat, poultry, fish, nuts, seeds, legumes and whole grain cereals.
• However, zinc from animal sources has higher bioavailability than plant sources. Plant sources contain fibre and phytate that inhibit zinc uptake by the intestine.
• Choose zinc rich foods as part of your healthy diet.

Sources

• Rich sources of dietary calcium include milk, cheese, yogurt and legumes.
• Choose foods high in calcium as part of your healthy diet.

Calcium content of selected foods

Note: DFE =Dietary Folate Equivalent
Source: Suitor & Baily (2000)
Cited in RNI for Malaysia (2005)

Sources

• Folate is available in a wide variety of foods particularly in legumes and green leafy vegetables.
• Include folate containing foods as part of your healthy diet.

Iodine Role of iodine Iodine is an essential element for your growth and development. It occurs in human body in only small amounts (15-20mg) and because of this, iodine is referred to as ‘trace element’. In human body, it is stored in the thyroid gland where it is used in the synthesis of thyroid hormones. The dietary requirement for iodine is important for the synthesis of thyroid hormones. Thyroid hormones are essential as they regulate protein synthesis and enzyme activities in muscles, brain, heart, kidney and pituitary gland. We only need a small amount of iodine and its requirement is as shown in the RNI for Malaysia 2005. Deficiency Inadequate iodine intake is associated with iodine deficiency. Iodine deficiency is a preventable cause of mental deficiency and cretinism, especially during pregnancy.

Sources

• Iodine is found in variable amounts in foods and drinking water.
• Foods such as clams, fish, crab, prawn, cuttlefish, oysters and other saltwater fish are the richest source of iodine. A wide variety of food also contains iodine such as eggs, meat, milk and milk products, cereal grains and dried fruits.
• Choose iodine-containing foods as part of your healthy diet.