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Nutritional anemia may be defined as the condition that results from the inability of the erythropoietic tissue to maintain a normal haemoglobin concentration on account of inadequate supply of one or more nutrients leading to reduction in the total circulating haemoglobin.
(Source: Dietetics by B. Srilakshmi)
Anaemia is caused by the absence of certain nutrients in the diet that is required in the formation of haemoglobin or by the poor absorption of these nutrients from the diet, hence low bioavailability.
Some anaemias are caused by:
Either lack of dietary iron or high quality protein,
Lack of pyridoxine(vitamin B6)- pyridoxine catalyses the haem portion of the haemoglobin molecule,
Lack of vitamin C- which helps the absorption of non-haem iron,
Lack of vitamin E- which affects the stability of the red blood cell membrane.
Lack of copper- copper helps in the absorption of iron, its release from the liver and its binding into the haemoglobin molecule.
Causes of anaemia in different age groups
Due to inadequate iron stores at birth due to low birth weight or due to preterm.
Infant who is breastfed by a mother who is a vegan.
Infant who is only taking milk without being weaned on proper foods.
Impaired absorption of folate
Gastrointestinal diseases such as regional enteritis, Crohn's disease and celiac disease.
Deficiency of nutrients in the diet
Due to hook-worm infestation-occult blood loss
Neglect of female child
Chronic intestinal blood loss induced by exposure to a heat labile protein in whole cow's milk.
At the time of menarche
Growth spurt with suboptimal hematopoietic contents.
Intensive exercise conditioning as occurs in competitive athletics iron depletion in girls
Early marriage with pregnancy
Excess blood loss during menstruation
Low maternal age
Infections which may interfere with intake, absorption and assimilation of nutrients
Cultural beliefs, taboos and inappropriate food practices
Pregnancy related complications
Dietary deficiency (folic acid)
Atrophic gastritis and bacterial over growth (B12)
Gastro intestinal blood loss from malignant disease, peptic ulcer disease
Drugs- Certain drugs interfere with the absorption of nutrients causing anaemia
Use of non-steroidal anti-inflammatory drugs.
Psychological problems- Old people may be depressed or stressed as a result of living lonely.
Loneliness- Old people may feel lonely due to the death of spouse or their children living elsewhere, therefore they may not feel like eating and enjoying food.
Poor absorption due to decreased secretion of gastric and intestinal juices.
Chronic inflammatory disease
Chronic infection-tuberculosis, malignancy
Gastrointestinal tract surgery
Blunting of the villi is present in advanced iron deficiency anaemia and may cause leakage of blood and decreased absorption of iron.
High amounts of tannic acid, oxalic acid and phytic acid in the diet which precipitates iron and renders it insoluble and unavailable.
Infestation with tapeworm-diphyllobothrium latum
An over growth of intestinal bacteria within diverticula or duplication of the small intestine may cause vitamin B12 deficiency by consumption of or competition for the vitamin or by splitting of its complex with intrinsic factor.
Drug induced anemia, methotrexate (an immune suppressive) interferes folic acid metabolism.
Some cancers (e.g., leukemia, lymphoma, and multiple myeloma)
Prevalence of anaemia
The prevalence of anaemia among female adolescents aged 12-19 years is 16.4%.
The prevalence of anaemia among pregnant women is 9 %.
The prevalence of anaemia among female adolescents aged 12-19 years is 27.0 %
More than 56 million women are estimated to be suffering from anaemia where at least 32 million are from Asia.
The National plan of action for nutrition (2009-2010) aimed to:
To reduce nutritional anaemia in female adolescents 12-19 years as indicated by haemoglobin levels under 12 g/dl, to 10%.
To reduce nutritional anaemia in pregnant women, as indicated by blood haemoglobin levels below 11 g/dl to 5%.
Types of anaemia
Hypochromic and Microcytic
When there is a lack of iron for the formation haemoglobin, the red blood cells are pale and small and the anaemia is referred to as hypochromic and microcytic.
This is caused by a deficiency of Vitamin B12 and folic acid as both of them are co-enzymes in the DNA synthetic pathway. A lack of the vitamins results in damaged or inadequate synthesis of DNA. Therefore, if the development of the red blood corpuscles in the bone marrow is impaired by insufficient folate or Vitamin B12, the cells which enter the blood stream are irregular in size and shape, but usually larger than normal, and contain their full complement of haemoglobin.
Dimorphic anaemia occurs due to a deficiency of both iron and either folate or vitamin B12.
Anaemia can also be caused due to the deficiency of nutrients such as copper, protein, energy, vitamin B6 and vitamin E.
Iron deficiency anaemia
This is the most common form of anemia throughout the world affecting mainly women in their reproductive years, infants and children. Iron is a component of haemoglobin, the substance which gives red blood cells their colour. Hemoglobin is required to transport oxygen around the body, to respiring tissues and cells, for the production of energy and for the maintenance of all cell functions.
Myoglobin holds oxygen in readiness for muscular work and also requires iron.
Cell enzymes, such as, cytochromes also contain iron.
Iron is stored in the liver, spleen and bone marrow in the form of specialized iron-binding proteins called ferritin and haemosiderin.
Oxygen molecules which have been absorbed through the alveolus of the lungs into the bloodstream attach themselves to haemoglobin in the red corpuscle and are transported round the body.
Causes of iron deficiency anemia
Insufficient iron intake
People who do not include iron-rich foods in the diet are at risk of developing anaemia.
Good sources include: Liver, kidney, plain chocolate, watercress, oats, and dates.
Reasonable sources include: White bread (added by law), curry powder, dried fruit, pulses, and wholegrain cereals, leafy green vegetables such as drumstick leaves, "brede malbar", and spinach amongst others.
Iron from plant sources is not as available as in animal sources. This is because iron found in plant sources is in its non-haem form which is not easily absorbed as haem iron found in animal sources. As such, only about 3-5% of iron is absorbed in a normal healthy person.
The average cereal legume based diets as consumed in most developing countries would appear adequate in iron content (20-22 mg) for an adult. However, the availability of iron from such diets is very poor.
A pregnant anemic mother gives birth to an infant whose iron stores are inadequate and in turn the infant is prone to get anaemia.
Insufficient absorption of iron
This can occur as in:
Diarrhoea (sprue and pellagra)
Lack of acid secretion by the stomach
In chronic renal diseases when antacid therapy is given.
Gastrectomy- Iron absorption is impaired by decreasing hydrochloric acid and transit time through the duodenum.
Excessive amounts of oxalates (present in spinach) in the diet renders iron insoluble
Phosphates (present in rhubarb and egg yolk) renders iron insoluble.
Phytates present in wholegrain cereals, pulses, renders iron insoluble.
Tannins present in tea, pulses, condiments, spices renders iron insoluble.
Too much dietary fibre present in plant foods also hinders the absorption of iron.
Not including enough vitamin C rich foods in the diet when including plant sources of iron in the diet.
Insufficient utilisation of iron
Due to chronic gastrointestinal disturbances, insufficient utilization of iron can occur. Moreover, defective release of iron from iron stores into the plasma and defective iron utilization due to chronic inflammation or other chronic disorder result in insufficient utilisation of iron.
A good supply of iron is required in:
Infancy- to cater for the expanding blood volume especially of premature infants and low birth weight infants as they may not have a sufficient store of iron.
Adolescence- For rapid growth, development of muscles and onset of menses in girls.
Pregnancy and lactation
If the required amount of iron is not supplied in these groups, iron deficiency anaemia can definitely occur. Furthermore, losses of iron can also occur due to excessive sweating in tropical climate.
Blood losses that result in anaemia can occur due to several causes namely:
Hemorrhage caused by accident,
Chronic diseases such as tuberculosis, ulcers or intestinal disorders,
Excessive blood donation
Excessive blood loss during menstruation and childbirth.
Perinatal bleeding may result from obstetric complications like placental abruption.
Prolonged periods of lactation deplete iron stores with each successive pregnancy.
Using intrauterine contraceptive device in women, menorrhagia (increased blood loss) may result in further depletion of already poor stores of iron.
Reappearance of malaria is also an important factor that causes anaemia.
Drugs that cause anaemia
Having drugs can alter nutrient metabolism, influence eythropoiesis and blood coagulation and sometimes lead to increased red blood cell destruction.
Anaemia can occur in patients who have chronic infections, inflammatory conditions, autoimmune disorders or cancer. Due to the inflammatory response macrophages in the liver, spleen and bone marrow the iron, making it unavailable for erythropoiesis and therefore slowing the rate of production of red blood cells. In addition red blood cells are destroyed more rapidly than usual and reduced production of red blood cells cannot keep pace. Iron absorption is reduced, possibly because intestinal cells inhibit release of iron into blood.
Diagnosis of anaemia
As the stages of iron deficiency progresses, this can be evaluated by four different measurements:
The plasma ferritin level gives a measure of iron stores.
Haemoglobin and hematocrit measurements can show the probability of getting anaemia. Most patients develop symptoms of anemia when the haemoglobin level is less than 10 g/dL
Transferrin saturation can be used as a gauge of iron supply to the tissues. If the level is less than 16 %, then it is considered to be insufficient for erythropoiesis.
Iron deficiency is a syndrome caused by malnutrition. Aside from anaemia, many clinical findings are observed namely:
Diminished work performance
Due to a lack of iron, myoglobin in muscle is affected and thus the muscles function inadequately. Therefore, there is decreased work performance and the patient cannot tolerate too much of exercise. This can have deep economic implications on the person and on the country also.
It has been shown that young adolescents, who are anaemic, usually score lower marks in tests of academic performance.
Decreased immune function
A deficiency of iron decreases the number of T-cells and the production of antibodies. Thus, a sign of early iron deficiency is reduced immune function, whereby cell-mediated reponse of antibodies and phagocytic action of neutrophils is impaired, which makes the individual prone to having infections.
Structure and function of epithelial tissues
The skin can appear pale
The inside of the lower eyelid may be light pink instead of red.
Finger nails may become thin, brittle and flat and eventually koilonychia (spoon-shaped).
The mouth changes- atrophy of the lingual papillae, a completely smooth waxy and glistening appearance of the tongue (glossitis).
Angular stomatitis and dysphagia
Gastritis occurs frequently and may result in achloryhydria.
If a chronic stage is reached and the condition remains untreated, cardiovascular and respiratory changes occur which can finally lead to cardiac failure.
Changes in behavior
Anaemic children are found to be particularly more irritable and restless in the classroom. Moreover, they may have craving for unusual non-food substances known as pica such as ice, dirt, and chalk among others. Breath holding spells and temper tantrums are also seen in these children.
Long- term iron deficiency symptoms show a malfunction of a variety of body systems. The symptoms are:
Breathlessness on slight exertions
Dimness of vision
Paraesthesia in fingers and toes
Growth abnormalities especially noted in children
Oedema of feet
Treatment of anaemia
Foods rich in iron must be taken- Red meat, seafood (fish and shellfish) and poultry are the best sources as they contain haem iron which is readily absorbed in the body.
Foods rich in iron
Clams, oysters, shrimp, crab muscle and sardines
Iron-fortified, ready-to-eat cereals and instant cooked cereals.
Green leafy vegetables- for examples, drumstick leaves, spinach, "brede malbar", cauliflower leaves, radish leaves, mint.
Organ meats (liver and giblets), liver sheep
Cooked dry beans and peas (white beans, lentils, chickpeas, kidney beans)
Dried fruits such as dates, prunes.
When foods from plant sources are taken, foods containing ascorbic acid must be consumed together and as far as possible, in the same meal, so that the iron can be converted in its haem form.
Foods that contain substances (phytates, oxalates, tannins) which can interfere with the absorption of iron must not be taken together with iron rich foods. Examples of such foods are: coffee, tea, egg yolks, phytates in fibre-containing foods.
Inorganic iron in the ferrous form- ferrous sulphate can be administered orally.
A second type of anaemia called pernicious anaemia involves vitamin B12. The body requires both vitamin B12 and folic acid for the synthesis of DNA to make new cells and healthy red blood cells. A deficiency of these nutrients can lead to pernicious anaemia.
Pernicious anaemia is a condition where the body cannot make enough red blood cells due to insufficient absorption of vitamin B12 from the diet. The body's inability to absorb vitamin B12 is due to a lack of intrinsic factor, a protein produced by the parietal cells of the stomach.
Causes of pernicious anaemia
Vitamin B12 is found exclusively in animal foods. A diet poor in animal foods and microorganisms such as yeast may lead to vitamin B12 deficiency. Alcoholism, poverty and dietary fads can also cause B12 deficiency. Breastfed babies of strict vegetarians and vegans are more prone because they are not able to store up enough vitamin B12 in their bodies.
Inadequate absorption and utilization
People who lack the intrinsic factor are unable to absorb vitamin B12. Conditions such as Addison's disease, type 1 diabetes, Graves' disease, and vitiligo can cause an autoimmune response which prevents the absorption vitamin B12. Furthermore, children are born with a condition called congenital pernicious anaemia. This disorder prevents their bodies from making intrinsic factor. Surgery to remove part or all of the stomach also can lead to a lack of intrinsic factor because the surgery removes the cells that make the protein.
Conditions in which too many bacteria proliferate too fast in the intestine can prevent the body from absorbing vitamin B12. The bacteria use up all the vitamin B12 before the intestine can absorb it. This is a common cause of pernicious anemia in older people.
Some gastrointestinal conditions, such as celiac disease and Crohn's disease, also interfere with vitamin B12 absorption. Tape worm infections also hinder absorption of Vitamin B12.
Signs and symptoms of pernicious anaemia
Tiredness as the body does not have enough red blood cells to carry oxygen to respiring tissues and cells.
Dizziness, palpitations and rapid heartbeats and shortness of breath.
Cold hands and feet.
Yellowish skin or pale skin, pale gums and nail beds.
Enlarged heart /heart failure
Digestive tract problems-such as nausea, poor appetite, weight loss, and diarrhoea.
Gastric secretions lack pepsin, acid and intrinsic factor.
Over a time, vitamin B12 can lead to nerve damage. This can cause symptoms such as tingling and numbness in the hands and feet, muscle weakness, problems walking, and irritability. Nerve damage also can cause problems such as memory loss, dementia (a loss of brain function), depression, and psychosis (mental illness). Dmyelination of white fibres of spinal cord occurs in severe cases.
Pernicious anaemia is associated with an increased risk of gastric cancer. Signs and symptoms are mental apathy, growth retardation and megaloblastic bone marrow. In young females there may be infertility.
Pernicious anaemia is diagnosed based on the following:
Medical and family history
Blood tests to see whether the red blood cells are larger than normal.
A reticulocyte count-This test measures the number of young RBCs in the blood. The results tell the doctor whether the bone marrow is making enough healthy RBCs. People who have pernicious anemia have low reticulocyte counts.
A test for blood levels of vitamins-This test measures level of vitamin B12, folate, and vitamin C in your blood.
Tests for homocysteine and methylmalonic acid levels-People who have pernicious anemia have higher than normal levels of these substances in their blood.
An antibodies test.-This test measures whether the body is making antibodies to attack the stomach cells that make intrinsic factor. Results of this test will show the cause of the pernicious anaemia.
Bone marrow tests- These tests show whether the bone marrow is healthy and making enough healthy red blood cells. People who have pernicious anaemia have larger than normal bone marrow cells.
If the haemoglobin level is under 4g/dl blood transfusion should always be given.
Physical activity should be less until the haemoglobin level is above 7g/dl
Shots of hydroxocobalamin of 1000 mcg should be given intramuscularly twice during the first week.
Folic acid must never be used alone in the treatment of pernicious anemia as it does not prevent the development of neurological disorders but may quicken them.
Plenty of foods that contain vitamin B12 must be taken:
Fish, shellfish, meat, and poultry
Eggs and dairy products (such as yogurt and cheese)
Breads, cereals, and other foods fortified with vitamin B12
Soy-based beverages and vegetarian burgers fortified with vitamin B12
A high protein diet of 100 to 150 g of protein is recommended- supplementation of liver extracts would be effective.
Achlorhydria retards digestion, hence a moderate amount of fat should be taken and fried foods must be avoided.
A soft/clear liquid diet is to be taken until glossitis disappears.
Spicy foods must be avoided to avoid irritation of GI tract.
High protein high calorie beverage two to three times daily must be given.
Foods containing ascorbic acid such as citrus fruits must be consumed.
To cope up with production of blood, ferrous sulphate of about 200 mg should be taken thrice daily.
Megaloblastic anaemia- folate deficiency
Megaloblastic anaemia is normally associated with malnutrition, infection and pregnancy where a deficiency of folate is likely.
Causes of megaloblastic anaemia
Poor dietary intake
The condition is common among poor vegetarians who do not consume enough milk, fresh fruits and vegetables. Moreover, folic acid is not a heat stable vitamin and is easily destroyed by prolonged cooking. Therefore, folic acid may not be available so much from the diet.
Megaloblastic anaemia is present in those infants' diet which is deficient in vitamin C as folic acid cannot be converted to its active form folinic acid. Coeliac disease and tropical sprue also decreases folic acid absorption from the gut. Folic acid absorption in pregnancy is impaired and babies born to mothers who have a deficiency of folic acid are also prone to be anaemic.
It has to be noted that Vitamin B12 deficiency can eventually result in folic acid deficiency.
During growth and pregnancy, the requirement for folic acid increases significantly and a deficiency may result in these stages of life. In hemolysis, when there is cell multiplication there is folic acid deficiency.
Infestation and infection
Chronic infections and parasitic infestation such as malarial infection may impair absorption of folic acid from the gut and cause megaloblastic anaemia.
Oral contraceptives may impair folic acid absorption in some women. Loss of folic acid occurs in hemodialysis. Drugs such as sulphasalazine, anticonvulsants hinder folate absorption resulting in anaemia.
Methetrexate (immune suppressive), triamterene (diuretic) and pyrimethamine (antimalarial) interfere in the metabolism of folate. Alcoholism also results in folic acid deficiency.
Signs and symptoms
The symptoms are generally same as in iron deficiency. However, glossitis is less common in vitamin B12 deficiency. Neurological complications are rare.
Haemoglobin levels may be as low as 4g/dL. Glossitis is often present but paraesthesia is a common sign.
FIGLU (formirnino glutamic acid excretion test) in the urine is a test of folic acid deficiency.
Level of folic acid in the plasma is less than 3 ng/ml.
There is free hydrochloric acid in gastric juice.
Level of homocysteine in the serum is increased during folate deficiency as homocysteine cannot be converted to methionine in the absence of folic acid.
A dose of 5 to 10 mg of folic acid should be taken daily.
Patients with less than 5g/dL of haemoglobin require blood transfusion.
Vitamin B12 of doses 10-15 microgram daily should be given as vitamin B12 work in conjunction with folic acid.
Foods rich in folic acid are:
Green gram dhall,
By regular consumption of green leafy vegetables, cereals such as whole wheat, pulses and foods of animal origin anaemia can be prevented. Fruits rich in vitamin C such as oranges, guavas and kiwi must be consumed to aid in the absorption of erythropoietic nutrients such as folic acid and iron.Research article