Vitamin Requirements

Minerals are inorganic compounds that work in coordination with the rest of the organic nutrients - macronutrients and vitamins - to guarantee the optimal result of a great number of processes that take place in our organism.

In a general sense, mineral needs increase in girls and boys during adolescence, due to the accelerated growth of bone tissue and the expansion of blood volume and muscle mass. In girls, iron requirements are significantly higher to compensate for menstrual losses.

Three minerals are of particular importance during adolescence:

• Calcium, because it is involved in the mineralization and growth of bone mass.

• Iron, for being part of hemoglobin and myoglobin, proteins necessary for the increase of blood volume and muscle mass.

• Zinc is involved in the development of muscle and bone mass and in the growth of nails and hair.

Calcium needs

Among the most demanded minerals during adolescence is calcium, necessary for its important role in the growth and formation of bone tissue in the first stages of life. The peak of calcium demand during adolescence occurs in girls around 13 years of age while in boys it occurs around 15 years of age, coinciding in both cases with peaks in growth rate.

Calcium deficiencies in adolescence can lead to the following disorders:

• Delay growth and affect the final height of the individual.

• Increasing the risk of osteoporosis later in life. This disorder is more frequent especially in women during postmenopause, causing fractures or micro fractures due to blows or falls.

  Excess calcium in adolescence can cause the following disorders:

• Constipation and renal alterations.

• Interferences in the absorption of other minerals such as iron and zinc.

Foods that provide calcium

• To ensure adequate calcium intake, the adolescent should drink three daily servings of milk or milk products. Dairy products are the ideal foods to meet the mineral demands of bone tissue, because in addition to supplying sufficient calcium, they provide the right proportion of phosphorus to calcium, for the formation and repair of bone tissue.
• Sardines, anchovies, vegetables, nuts, leguminous plants provide calcium in smaller proportions.

Elements that favor calcium absorption: vitamin D, magnesium and lactose.

Elements that hinder calcium absorption:

• Excesses of phosphorus and proteins in the diet.

• The consumption of alcoholic beverages, coffee and caffeine-containing beverages that inhibit its absorption.

  The following table shows the recommended calcium intakes for the Spanish adolescent population.

Iron requirements

Iron needs are increased in adolescence due to three main reasons:

• Increase in hemoglobin caused by the increase in blood volume: iron constitutes a component of hemoglobin, therefore the increase in hemoglobin must be supported by increased intakes of this mineral.
• Increase in muscle mass: Iron is part of myoglobin, a protein responsible for storing oxygen in muscle tissue, so higher levels of iron are required to ensure an increase in muscle mass in adolescents.
• Onset of menstruation in women: Iron needs are greater in the female sex, to compensate for losses due to menstrual bleeding.

Iron deficiencies in adolescence can lead to the following disorders:

• Iron deficiencies can eventually lead to iron deficiency anemia; a clinical sign that causes dizziness, fatigue and headaches among other symptoms.
• They reduce immune function.
• It causes difficulties in concentrating attention and reduces the adolescent's ability to learn.

Foods that provide iron

Iron-containingfoods: Iron is available in a large number of foods in two different forms:

• Heme iron: It is found in the heart, kidneys, liver, red meat, poultry, fish and eggs. Heme iron is m