ANAEMIA

Posted by Rashi Mundhra on Tue, Mar 27, 2012  
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Blood is the only fluid tissue in the body. It is constantly changing and a highly complex structure. Its intricate function and composition suggests for a need of a variety of nutrients. The functions of blood are as follows:

  1. Supply of oxygen to the tissues
  2. Supply of nutrients such as glucose, amino acids and fatty acids
  3. Removal of wastes such as carbon dioxide, urea and lactic acid
  4. Immunological functions including circulation of white blood cells, and detection of foreign material by antibodies.
  5. Messenger functions that is transport of hormones and the signaling of tissue damage
  6. Regulation of body pH

Anemia is a condition in which a deficiency in the size or number of erythrocytes or the amount of hemoglobin limits the exchange of oxygen and carbon dioxide between the blood and the tissue cells. Classification is based on cell size: macrocytic (large), normocytic (normal), and microcytic (small). And also based on the hemoglobin content: hypochromic (pale colour) and normochromic (normal).

Most anemias are caused by a lack of nutrients required for normal erythrocyte synthesis, principally iron, vitamin B12, and folic acid. Others result from a variety of conditions such as hemorrhage, genetic abnormalities, chronic disease states, or drug toxicity. The anemias that result from inadequate intake of iron, protein, certain vitamins (like B12, folic acid, pyridoxine, and ascorbic acid), copper, and other heavy metals are frequently called as nutritional anemias.

Today we shall focus on Iron Deficiency Anemia:

It is characterized by the production of small (microcytic) erythrocytes and a dimished level of circulating hemoglobin. This microcytic anemia is actually the last stage of iron deficiency and it represents the end point of a long period of iron deprivation.

PATHOPHYSIOLOGY:

The condition can arise from:

  1. Inadequate iron intake secondary to a poor diet
  2. Inadequate absorption resulting from diarrhea, achlorhydria, intestinal disease such as celiac disease, atrophic gastritis, partial or total gastrectomy, or drug interference
  3. Inadequate use secondary to chronic gastrointestinal disturbances
  4. Increased iron requirements for growth of blood volume, which occurs during infancy, adolescence, pregnancy and lactation.
  5. Increased excretion because of excessive menstrual bleeding in females; hemorrhage from injury; or chronic blood loss from a bleeding ulcer, bleeding hemorrhoids, esophageal varices, regional enteritis, ulcerative colitis, parasites or malignant disease
  6. Defective release of iron from iron stores into the plasma and defective iron use owing to a chronic inflammation or other chronic disorder.

STAGES OF DEFICIENCY:

Stage 1: Moderate depletion of iron stores. No dysfunction.

Stage 2: Severe depletion of iron stores. No dysfunction.

Stage 3: Iron deficiency. Dysfunction.

Stage 4: Iron deficiency. Dysfunction and Anemia.

CLINICAL FINDINGS:

EARLY:

  1. Inadequate muscle function
  2. Growth abnormalities
  3. Epithelial disorder
  4. Reduced immunocompetence
  5. Fatigue

LATE:

  1. Defects in epithelial tissue
  2. Gastritis
  3. Cardiac failure

DIAGNOSIS:

Progressive stages of iron deficiency can be evaluated by six different measurements:

  1. Quantity of serum or plasma ferritin
  2. Quantity of serum or plasma iron
  3. Quantity of circulating transferring
  4. Percent saturation of circulating transferring, which measures the iron supply to the tissues
  5. Percent saturation of ferritin with iron
  6. Quantity of soluble serum transferring receptors (SFTR): Transferrin molecules are generated on the red blood cells in response to the need for iron. With iron deficiency, so many transferring receptors are on the cell surface looking for iron that some of them break off and float in the blood. Their presence is an early measurement of developing iron deficiency, with a higher quantity meaning greater deficiency of iron.

MEDICAL NUTRITION THERAPY:

In addition to the iron supplementation, attention should be given to the amount of absorbable dietary iron consumed. A good source of iron contains a substantial amount of iron in relation to its caloric content. Liver; beef; kidney; dried peas and beans; dried fruits; nuts; green leafy vegetables; fortified whole grain breads, muffins, cereals and nutrition bars are among the foods that rank highest in the iron content.

It is estimated that 1.8mg of iron must be absorbed daily to meet the needs of 80% to 90% of adult women and adolescent males and females.

BIOAVAILABILITY OF DIETARY IRON:

Several factors influence the bioavailability of dietary iron. They are:

  1. Bio availability from animal foods called as haem iron is about 25% as compared to 5-15% in plant foods that is non haem iron.
  2. Absorption is maximum up to 50% when the body stores are low, requirements are more or losses are more.
  3. Meat protein factor
  4. Vitamin C intake
  5. Gastric acidity

Factors that decrease the absorption of iron are:

  1. Low need for iron in other words high iron stores
  2. Phytic acid in whole grains and legumes
  3. Oxalic acid in leafy vegetables
  4. Polyphenols in tea, coffee, red wine and oregano
  5. Reduced gastric acidity
  6. Excessive intake of other minerals like zinc, calcium, manganese

INCREASED RISK OF IRON DEFICIENCY:

Increased risk is observed in:

  1. Women
  2. Growing children and adolescents
  3. Pregnancy
  4. Heavy menstruation
  5. Chronic bleeds
  6. Hemorrhoids
  7. Peptic ulcers
  8. Irritation from drugs or alcohol
  9. Acute gastritis
  10. Iron poor diets
  11. Strict vegetarians
  12. Heavy tea/coffee drinkers
  13. Reduced gastric acid secretion
  14. Stomach surgery
  15. Chronic antacid use

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