Definition
Anemia is a relatively common health condition characterized by a lack of red blood cells. Red blood cells are cells found in the blood. Among other things, they serve to supply oxygen to tissues and organs.
People with anemia may feel tired and run out of breath more easily than usual because their heart has to work harder to supply their body with oxygen.
According to the World Health Organization, 25% of the world's population suffers from anemia. Half of these cases are attributed to nutritional iron deficiency. Women who have heavy periods, preschool children, and pregnant women are most at risk of anemia.
The life of a red blood cell
The kidneys secrete a hormone, erythropoietin, which causes the bone marrow to produce new red blood cells. These globules circulate in the blood for 120 days. Then they are destroyed in the spleen. Every day, about 1% of red blood cells are renewed.
Causes
Several situations can give rise to anemia.
- An iron deficiency.
- Vitamin deficiency.
- A chronic illness or disease of the bone marrow.
- A genetic disease, which causes, for example, too rapid destruction of red blood cells.
- Hemorrhage, which is blood leaking out of the blood vessels.
Red blood cells, iron and hemoglobin
Red blood cells are blood cells mainly made up of hemoglobin. Hemoglobin is made up of a protein (globin) and a pigment (heme). It is the latter that gives the red color to the blood. It binds iron which carries oxygen from the lungs to the cells. Oxygen is necessary for the production of energy in cells and allows organs to perform their functions. The oxygen-bound pigment takes on a vermilion-red hue and circulates through the arteries. Hemoglobin also carries carbon dioxide (waste from the combustion of oxygen) from cells to the lungs. It then turns purplish red and circulates through the veins.
Main types of anemia
Iron deficiency anemia. It is the most common form of anemia. Heavy periods and a diet low in iron are the most common causes. Iron deficiency anemia changes the size of red blood cells, which become smaller than normal (microcytic anemia).
Vitamin deficiency anemia. This type of anemia produces deformed and very large red blood cells (macrocytic anemia). The most common are those caused by vitamin B12 or vitamin B9 (folic acid) deficiency. The first can occur due to an insufficient dietary intake of this vitamin, its poor absorption in the intestine or a condition called pernicious anemia.
Anemia caused by a chronic disease. Many chronic conditions (and sometimes their treatments) can reduce the amount of circulating red blood cells in the blood. This is the case with cancer, Crohn's disease and inflammatory diseases such as rheumatoid arthritis. Kidney failure can also cause anemia because the kidneys secrete erythropoietin, the hormone that stimulates the production of red blood cells. However, these retain their normal size and appearance (normocytic anemia).
Hemorrhagic anemia. Severe blood loss after a serious accident, surgery or childbirth, for example, can quickly cause anemia. Certain gastrointestinal problems (a peptic ulcer, intestinal polyps or colorectal cancer) can also lead to it, but this time by causing a slight and constant loss of blood in the stool (sometimes invisible), over a long period.
Hemolytic anemia. This type of anemia is characterized by too rapid destruction of red blood cells. It can be attributable to an immune system reaction (autoimmune or allergic), to the presence of toxins in the blood, to infections (for example, malaria), or even to be congenital (sickle cell anemia, thalassemia, etc.). The congenital form mainly affects individuals of African origin.
Sideroblastic anemia. This term covers a group of very rare anemias in which red blood cells cannot fix iron in hemoglobin. It is an enzymatic problem of hereditary or acquired origin. The red blood cells are then smaller than normal.
Aplastic anemia. This rare disease occurs when the bone marrow no longer produces enough blood stem cells. Thus, there is not only a lack of red blood cells, but also white blood cells and blood platelets. In 50% of cases, aplastic anemia is caused by toxic agents, certain medications or exposure to radiation. It can also be caused by serious illnesses, such as bone marrow cancer (for example, leukemia).
Diagnostic
Since symptoms alone cannot be used to make a diagnosis, it is necessary to undertake a laboratory examination of a blood sample. A complete blood count (hemogram) is normally prescribed by the doctor.
Here are the 3 main parameters:
- Hemoglobin level: the concentration of hemoglobin (the respiratory pigment contained in red blood cells) in the blood, expressed in grams of hemoglobin per liter of blood (g/l) or per 100 ml of blood (g/100 ml or g/dl).
- Hematocrit level: the ratio, expressed as a percentage, of the volume occupied by the red blood cells of a blood sample (passed through the centrifuge) compared to the volume of whole blood that this sample contains.
- Red blood cell count: The number of red blood cells in a given volume of blood, normally expressed as millions of red blood cells per microliter of blood (millions/µl).
Normal values
Settings | adult woman | adult male |
Normal hemoglobin level (in g/l) | 138 ± 15 | 157 ± 17 |
Normal hematocrit level (%) | 40,0 ± 4,0 | 46,0 ± 4,0 |
Red blood cell count (millions/µl) | 4,6 ± 0,5 | 5,2 ± 0,7 |
Remark. These values of hemoglobin level and hematocrit level correspond to the norm for 95% of people. This means that 5% of individuals have abnormal values while being in good health. On the other hand, results at the lower limits of normal may reflect the onset of anemia if they were usually higher.
Other blood tests may be required to help establish a diagnosis and find the cause of the anemia. Depending on the case, we can carry out the examination of the size of the red blood cells, the dosage of iron or of different vitamins in the blood, etc.
Symptoms of anemia
Most people with mild anemia don't notice it. The intensity of the symptoms varies according to its severity, the type of anemia and its speed of onset. When anemia comes on gradually, the symptoms are less obvious. Here are the main symptoms.
- Tiredness
- Pale skin
- Acceleration of the heart rate and more pronounced shortness of breath on exertion
- Cold hands and feet
- Headaches
- Dizziness
- Greater vulnerability to infections (in case of aplastic anemia, sickle cell anemia or hemolytic anemia)
- Other symptoms may appear in some severe forms of anemia, such as pain in the limbs, abdomen, back or chest, visual disturbances, jaundice and swelling in the limbs.
Note. Anemia increases the risk of death from disease, heart attack or stroke in older people.
People and risk factors for anemia
People at risk
- Women with heavy periods.
- Pregnant or breastfeeding women, as they are at higher risk of nutritional deficiencies.
- People whose heredity predisposes them to anemia.
- People with a chronic disease, autoimmune disease, or gastrointestinal disorder (which may cause bleeding or interfere with nutrient absorption).
- The elderly, as the absorption of vitamins may be compromised.
- People exposed to nuclear radiation or who have received radiotherapy treatments for cancer.
- People with a serious viral infection, such as hepatitis or human immunodeficiency virus (HIV).
Risk factors
- A diet deficient in iron, vitamin B9 (folic acid), or vitamin B12. Vegans are at higher risk for vitamin B12 and iron deficiency because they don't consume animal protein.
- Alcoholism.
- Consumption of certain medications. For example, nonsteroidal anti-inflammatory drugs (NSAIDs) and blood thinners can cause internal bleeding.
- Other drugs may interfere with the absorption or metabolism of folic acid. Examples include Dilantin®, an anticonvulsant, and methotrexate, an immunosuppressant. They can cause folic acid deficiency anemia when taken long term. The risk is increased in people whose folic acid stores are low. Because this interaction is well known, people who need to take this type of medication are also prescribed folic acid supplements.
- Exposure to certain chemicals, including lead.
Prevention of anemia
Basic preventive measures
Most anemias related to dietary deficiency can be prevented by the following measures.
Eat a diet that contains enough iron, vitamin B12 and folic acid. Pregnant or breastfeeding women, those with heavy periods and people whose diet includes little or no intake of animal products should pay particular attention. The body can store folic acid for 3-4 months, while vitamin B12 stores can last 4-5 years. As for iron: a 70 kg man has reserves for about 4 years; and a 55 kg female, for about 6 months.
- Main natural sources of iron: red meat, poultry, fish and clams.
- Main natural sources of vitamin B12: animal products and fish.
- Main natural sources of folate (folic acid in its natural form): organ meats, dark green leafy vegetables (spinach, asparagus, etc.) and legumes.
For women planning a pregnancy, in order to prevent spina bifida in the fetus, it is recommended to start taking folic acid (400 mcg of folic acid daily with food) at least 1 month before conception and to continue during the first months of pregnancy.
In addition, since the birth control pill depletes folic acid, any woman who decides to have a child should stop contraception at least 6 months before conception so that the fetus can benefit from a sufficient quantity of folic acid during the early stages of sounddevelopment.
Other preventive measures
If you have a chronic condition that can cause anemia, it is important to have proper medical follow-up and occasional blood tests. Discuss it with your doctor.
Take all the necessary precautions if you have to handle toxic products.
Medical treatments for anemia
Treatments vary depending on the type of anemia. People with fragile health or suffering from another disease (cancer, heart disease, etc.) are those who feel the benefits of treatment the most.
- Stop taking the drug that is causing the anemia or exposure to a toxic product.
- Correct a deficiency in iron (by mouth), vitamin B12 (by mouth or injections) or folic acid (by mouth), if necessary.
- For women with heavy periods, hormone therapy may help (birth control pill, IUD with progestogen, danazol, etc.).
- Optimally treat the chronic disease causing the anemia. Often, adequate treatment of the latter is enough to make the anemia disappear.
- In case of sideroblastic anemia, taking pyridoxine (vitamin B6) can contribute to the treatment.
- In case of acquired (non-congenital) hemolytic anemia, immunosuppressants and corticosteroids are prescribed.
- In the case of sickle cell anemia, the painful attacks are relieved with the help of painkillers.
- In severe anemia, injections of synthetic erythropoietin, blood transfusion or bone marrow transplantation may be considered, as appropriate.
Special care
For people with aplastic anemia, hemolytic anemia or sickle cell anemia, certain precautions are necessary.
Guard against infections. Aplastic anemia, which also affects white blood cells, increases vulnerability to infections. Wash hands often with antiseptic soap, avoid contact with sick people, get enough sleep, get vaccinated and take antibiotic therapy as needed.
Hydrate well. Poor hydration increases blood viscosity and can cause painful crises or lead to complications, especially in the case of sickle cell anemia.
Avoid excessively intensive exercises. For one thing, even light exercise can cause fatigue in an anemic person. On the other hand, in case of prolonged anemia, it is important to spare the heart. This one has to work a lot more because of the deficient transport of oxygen linked to anemia.
Watch out for impacts, cuts and injuries. In people who have a low level of blood platelets, the blood clots less well and blood loss should be avoided as much as possible. For example, shaving with an electric razor rather than a blade, preferring soft-bristled toothbrushes and refraining from practicing contact sports.
Complementary approaches to anemia
Therapeutic touch. Only one randomized clinical trial has been published on this subject. In this trial, involving 92 college students with anemia, subjects in the experimental group received 3 therapeutic touch treatments for 15 to 20 minutes, 3 days apart. The subjects in the placebo group received, at the same frequency, treatments simulating the movements of therapeutic touch and the subjects in the control group received no intervention. The results indicate an increase in hemoglobin and hematocrit levels both in the subjects of the experimental group and in those of the placebo group, unlike the control group. However, the increase in hemoglobin levels was greater in the therapeutic touch group than in the placebo group.
Chinese pharmacopoeia. Various decoctions that serve to tonify the Kidneys and regenerate the Blood are used in Traditional Chinese Medicine to treat anemia. Traditionally, Chinese doctors also use cordyceps and velvet antler, a velvety substance that coats the antlers of red deer and elk.