Answers
Calcium is essential for healthy bone growth and for nerve and muscle functions; it may protect against high blood pressure. Calcium is the most abundant mineral in the body. Most of the calcium in the body is located in the bones, providing a “storage bank” to maintain maximum calcium storage throughout life. Stored calcium is released into the body when needed to maintain a constant level in the blood for important body functions such as muscle movements (contract and relax) and transmitting nerve impulses. Without an exact level of calcium in the blood, our heart would not be able to beat and we would not be able to breath or move.
Adequate calcium intake is important at all stages of life.
In childhood and adolescence, it is particularly important to eat and drink calcium rich foods to ensure maximum calcium storage and strong bones. This is because calcium is most easily absorbed into the bones until late adolescence, after which the ability to store calcium slows down and becomes more difficult. Calcium needs are high during pregnancy, when the infant’s bones are developing, and even more so in breastfeeding, when high levels of calcium are passed to the baby through the breastmilk. Later in life, when storage levels are low, it is also important to increase calcium in the diet in order to protect bones from further calcium loss and to prevent osteoporosis, a disease resulting from lack of calcium, in which bones become weak and brittle and can easily break.
The best sources of calcium are: milk, cheese and yoghurt; small fresh or dried fishes with the bones and fish sauces containing the fish bones; white beans; tofu (soybean); almonds and sesame seeds. Some vegetables and leafy greens, such as broccoli and spinach, contain calcium, but large quantities of these foods must be eaten to ensure sufficient calcium.
Iron is needed in the blood and muscles as part of the system that carries oxygen throughout the body to be used for energy production in the cells.
Iron is also involved in getting energy from carbohydrates, protein and fats and is needed for making amino acids and body tissues. Iron needs are greatest during periods of growth and development, so infants, children and pregnant women have the highest needs. Iron deficiency anaemia, which occurs when iron is low, contributes to deaths in pregnancy and childbirth and can result in poor growth and development, low resistance to disease, poor reproductive functions and lower resistance to infections leading to increased illness.
Sources of iron: Iron is found in both animal and plant foods, but the iron in animal foods is in a form that is very easy for the body to absorb and use, while iron from plant foods is not as easily absorbed or used by the body. Good animal sources of iron are: meat, especially red meat, liver, eggs, fish and poultry. Plant sources of iron include beans, soybeans and tofu, leafy green vegetables, dried fruits and foods fortified with extra iron, such as enriched bread.
Vitamin C can help the body’s ability to absorb iron, so eating iron-rich foods together with foods such as lemons, limes, oranges, grapefruits, tomatoes and strawberries will increase the iron we get from foods. Other food components, such as phytates in bran and tannins in teas, can inhibit the absorption of iron and other minerals.
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