BSc Nursing 1 St Year Nutrition And Biochemistry Nursing Chapter 7 Minerals Question And Answers

Minerals

Question 1. Classification of minerals.
Answer.

The mineral elements constitute only a small proportion of the body weight and there is a wide variation in their body content

Minerals perform several vital functions which are absolutely essential for the existence of man

These functions include calcification of bone, blood clotting, neuromuscular irritability, acid base balance and water-electrolyte balance.

Classification

The elements of the body are divided into 5 major groups

Group 1

• These are components of macromolecules such as carbohydrates, proteins and lipids.
• Examples
  • Carbon (C)
  • Hydrogen (H)
  • Oxygen (O)
  • Nitrogen (N)

Group 2

• These are nutritionally important minerals or principal elements
• Their daily requirement is more than 100 mg
• Their deficiency can prove fatal
• They are also known as macro elements
• Examples
  • Sodium (Na)
  • Potassium (K)
  • Chloride (Cl)
  • Calcium (Ca)
  • Phosphorus (P)
  • Magnesium (Mg)
  • Sulfur (S)

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Group 3

• These are known as trace elements
• They are essential elements and their requirement is less than 100 mg
• Their deficiency can lead to serious disorders
• Examples
  • Chromium (Cr)
  • Cobalt (Co)
  • Copper (Cu)
  • Iodine (I)
  • Iron (Fe)
  • Manganese (Mn)
  • Molybdenum (Mb)
  • Selenium (Se)
  • Zinc (Zn)

Group 4

• These are additional trace elements
• They may be possibly essential
• Their exact role is not known
• Examples
  • Cadmium (Cd)
  • Nickel (Ni)
  • Silicon (Si)
  • Tin (Sn)
  • Vanadium (Vn)

Group 5

• These are not essential elements and may be toxic
• They have no known function in the body
• They may enter the body through polluted air, water, soil or food
• Examples
  • Arsenic (As)
  • Cyanide (Cn)
  • Mercury (Hg)

Question 2. Functions of minerals.
Answer.

Functions

Intracellular calcium is involved in:

• Muscle contraction.
• Release of hormones, neurotrausmitter and neuromodulators.
• Activation of a number of enzymes.
• Glycogen metabolism.
• Cell division.

Extracellular calcium provide calcium ion for the:

• Maintenance of intracellular calcium.
• Bone mineralisation.
• Blood coagulation.
• Membrane excitability.
• Plasma membrane potential.

Question 3. Factors affecting iron absorption.
Answer.

Factors Which Decrease Iron Absorption

• Phytates present in corn, soya and cereals decrease iron absorption
• Oxalates, present in leafy vegetables and chocolates decrease iron absorption
• A diet with high phosphorus content decreases iron absorption
• Tea, coffee and eggs decrease iron absorption
• Dietary fibers decrease iron absorption
• Alkaline pH decreases iron absorption
• Impaired absorption of iron is found in malabsorption syndromes such as steatorrheoa
• In patients with partial or total surgical removal of stomach / intestine, iron absorption is impaired
• Parasitic infection (hookworm) decreases iron absorption

Question 4. Write sources and effect of deficiency of iron.
Answer.

Dietary Sources

• Rich sources – organ meats (liver, heart and kidneys)
• Good sources – leafy vegetables, pulses, cereals, fish, dried fruits, apple and meat
• Poor sources – milk, wheat and rice
• Haeme iron which comes from animal products and is from haemoglobin and myoglobin is efficiently absorbed (20 to 30 %)
• Non haeme iron which is present in plants is inefficiently absorbed (1 to 5 %)

Clinical Features Of Iron Deficiency

• Hypochromic microcytic anemia
• Blood Hb below 12gm %
• Apathy – dull and inactive
• Sluggish metabolic activities
• Retarded growth
• Loss of appetite
• Serum ferritin decreased
• Serum transferrin decreased
• RBC protoporphyrin increased

Question 5. Functions Of Calcium.
Answer.

Functions Of Calcium

• Calcium is required for bone formation
• Calcium plays a role in muscle contraction Calcium increases the interaction between actin and myosin
• Calcium is necessary for transmission of nerve impulse
• Calcium influences cell membrane structure
• Calcium plays a role in the transport of water and ions across the cell membrane
• Calcium activates the enzymes pancreatic lipase, ATPase and succinate dehydrogenase
• Calmodulin is a calcium binding regulatory protein Calcium calmodulin complex activates the enzymes adenylate cyclase and protein kinase
• Certain hormones exert their action through the mediation of calcium and thus calcium acts as a second messenger or third messenger for such hormonal action e.g. – epinephrine and anti diuretic hormone
• Calcium is required for the release of certain hormones from the endocrine glands e.g. insulin, parathyroid hormone and calcitonin

Question 6. Write the factors interfering in absorption of calcium.
Answer.

Factors Which Interfering In Calcium Absorption

• Phytates present in cereals form insoluble calcium salts and inhibit calcium absorption
• Oxalates present in vegetables like cabbage and spinach form insoluble calcium salts and inhibit calcium absorption
• High content of dietary phosphorus results in the formation of insoluble calcium phosphate and inhibits calcium absorption
• Free fatty acids inhibit calcium absorption by reacting with calcium to form insoluble calcium soap . This is particularly observed when fat absorption is impaired
• High pH (alkaline conditions) inhibits calcium absorption
• High content of dietary fibers interferes with calcium absorption
• High content of magnesium in the diet decreases calcium absorption
• High content of iron in the diet inhibits calcium absorption.