deficiencies can lead to anaemia
is the very essence of life and nature has devised a very ingenious
method to continuously supply blood to every part of the body, in fact
every cell of the body. Oxygen along with other nutrients is supplied
continuously by the circulating blood, with the heart at the center of
this system. Oxygen is required for all metabolic functions of the
cells and production of energy for these activities. Blood consists of
various cells, including red blood cells which contain hemoglobin,
white blood cells which are the basis of the body’s defence
mechanism and immunological functions of the body and platelets which
are required for plugging any breach or leak in the circulating
vessels. The liquid part of the blood, known as plasma, contains
various proteins, salts, enzymes, hormones and many other important
chemicals. Red blood cells (RBCs) contain hemoglobin which imparts a
red colour to the blood and it consists of four amino acid chains and
iron containing moiety known as heme. Oxygen is transported by the
heme from the lungs to the tissues. Normally an average adult male has
about 15 gm of hemoglobin and female about 14 gm per 1000 milliliters
of the blood. Interestingly, during foetal life and at birth the
hemoglobin is about 17-18 gm and any in excess of this is destroyed
during the first few days of life. The red blood cells which contain
hemoglobin are about 8 microns in size, discoid in shape and very
pliable so that they can travel through the very narrow thread-like
capillaries. These cells are produced in the hollow of the long and
flat bones and have an average life of about 120 days and are
continuously replaced. On an average about 1 per cent of red blood
cells are replaced every day.
The word anaemia in Greek means a lack of blood. Actually it is a deficiency of hemoglobin and there are various grades of this deficiency. Anaemia can result from a large number of causes, including nutritional deficiencies, acute or slow loss of blood due to trauma or diseases, destruction of red blood cells due to various metabolic and immunological abnormalities or toxins, disease of the bone marrow, general systemic diseases like infections and variouses varieties of cancers, kidney failure because kidney produces an important hormone, erythropoietin, which is required to stimulate the bone marrow to produce red blood cells and finally there may be genetic abnormalities in the formation of the hemoglobin molecules itself. The best-known examples of these abnormalities are thalassemia and sickle cell disease. In this write-up we will mainly concern ourselves with the nutritional aspect of anaemia because that is where public awareness can help in the prevention and treatment of this disease.
Nutritional basis of anaemia
There are three critical nutrients which are required in the formation of red blood cells and hemoglobin in particular. These include iron and two important groups of Vitamin B complex folic acid and cobalt containing Vitamin (B12) known as cobalamine. There is a widespread deficiency of these nutrients producing anaemia of various grades in the population. The iron-deficiency anaemia particularly is widely prevalent all over the world, specially in the deprived sections of the population in the developing countries. It is estimated that half a billion of the world population may have iron-deficiency anaemia. In India, according to an estimate, 20 per cent of adult males, 40 per cent of children and non-pregnant females and 60-80 per cent of pregnant females suffer from iron-deficiency anaemia. Normally we require about 10-15 mgs of iron in the diet out of which hardly 10 per cent is absorbed. But the actual requirement of iron in the body is about 1 mg in the males and 4 mg in the females. In spite of this relatively small requirement, there is a widespread deficiency of this nutrient. Iron is available in large amounts in red meat, liver, egg yolk, bone marrow and for vegetarians it is contained in fruits, leafy green vegetables, dry fruits and jaggery. Milk is a poor source of iron. Iron is also available in cereals but it is often lost during refinement and processing. This is true of both wheat and rice. In spite of this wide distribution in food, iron deficiency is prevalent because of poor intake of food due to poverty, decreased absorption due to various gastrointestinal diseases, blood loss due to ulcers, piles and excessive loss during menses in the females and increased requirement during adolescence, pregnancy and lactation. In the elderly population this may be both due to dietary deficiency as well as a lack of acid in the stomach which is required for the absorption of iron.
Anaemia due to iron deficiency can be recognised easily on clinical examination and by laboratory tests in which the iron levels in the blood, bone marrow and various other tests can show if there is a deficiency of iron. This can be corrected through dietary management and iron therapy which can be given in the form of tablets or syrup, if required, by intramuscular or intravenous injections. The last route is used only in special cases and is not preferred because of risk of allergic reactions. If the hemoglobin level is very low (less than 6 gm) or if the anaemia needs to be corrected on an urgent basis, for instance before performing surgery, the initial correction can be made by blood transfusion. But there is no doubt that preventive measures in the form of dietary management and taking measures to correct losses or malabsorption are the preferred methods of treatment.
Folic acid and B12 deficiency
The other two components required for blood formation are required for rapidly growing cells in the body, including red blood cells. These two nutrients are required for the formation of nucleic acids required in the early stages of the growth of these cells. Folic acid and B12 are required in the formation of nucleic acid in various enzymatic reactions and if they are deficient, the size of the red blood cells grows bigger than normal and that is why this type of anaemia is also known as megaloblastic anaemia. Folic acid is available in green leafy vegetables, fruits, liver and other glandular meat. Eggs and milk are relatively poor sources of folic acid. The daily requirement is about 50-100 micrograms but increases during pregnancy. In spite of fairly widespread distribution in food substances folic acid deficiency is common due to lack of proper food intake, overlooking specially boiling of food, old age, alcoholism, pregnancy, lactation and premature births. Intestinal diseases can impair absorption of folic acid even if it is present in the diet and many drugs can decrease its utilisation when it is absorbed. Folic acid deficiency can be treated with oral tablets and if required, can also be injected. Using supplements of folic acid during pregnancy is necessary and should be a routine. In the USA folic acid deficiency has drastically come down after the introduction of mandatory fortification of bread with folic acid, something like iodisation of salt in our country.
Vitamin B 12, on the other hand, is available only through animal sources, including milk. This is readily available in the red meat, liver, egg and yeast. Vegetarians, therefore, find it difficult to fulfil their requirement for this vitamin. Its requirement is very small and we hardly need 1-2 micrograms of this vitamin per day. An average diet should contain enough of Vitamin B12. But this is also destroyed during cooking and diseases of the stomach and intestine can impair the absorption of this vitamin. There is a specific type of anaemia known as pernicious anaemia in which the mechanism of absorption is impaired because of deficiency of a special protein in the stomach known as intrinsic factor. In this form of anaemia, in addition to low hemoglobin, problems with the nervous system can also occur. B12 deficiency is usually treated by injections but crystalline form of B12 than can be taken orally is also available. Usually a injection containing 1000 micrograms once a month is enough to meet the requirement.
Anaemia is a debilitating disease and
even though its diagnosis is fairly simple patients do not go to a
doctor in time. Anaemia that develops rapidly due to blood loss or
hemolysis is usually readily diagnosed and treated. In fact, if blood
loss is marked it will not only give rise to symptoms of anaemia but
also lead to vascular collapse which needs immediate treatment by
blood transfusion. But anaemia that develops gradually due to
nutritional factors or chronic blood loss is often missed because the
patient goes on adjusting to the slowly declining hemoglobin level.
One often comes across patients with a hemoglobin of just 6-7 gms who
do not seem to complain too much about it. But this not to suggest
that this should be accepted or is totally harmless. These people
actually experience fatigue, weakness, breathlessness and palpitation
on exertion. They are unable to perform any physical activity
requiring muscular work. The functions of various organs like the
heart, brain and eyes and impaired. Their nails are brittle and often
show flattening or spooning, specially in iron-deficiency anaemia. The
population which should be specially screened for anaemia includes
infants, adolescents, adults, females, specially during pregnancy and
lactation, and elderly population with decreasing food intake and
chronic gastrointestinal problems. For x other than the one caused by
nutritional factors expert medical advice should be taken.