Anemia: prevention, diagnosis, and when to see a doctor

Anemia rarely appears suddenly: it is usually preceded by months of gradual depletion of iron or vitamin stores. This means that in most cases it can be detected early and prevented. The editorial team explains how to organize prevention, which tests are truly informative, and when a drop in hemoglobin is grounds for seeing a doctor immediately.

Symptoms worth paying attention to

The early signs of anemia are nonspecific: fatigue, decreased endurance, shortness of breath on usual exertion, rapid heartbeat, headache, dizziness on standing. An athlete often notices that the usual pace has become harder and recovery takes longer.

External manifestations are pallor of the skin and mucous membranes, brittle nails, hair loss, cracks in the corners of the mouth. With pronounced iron deficiency, pica occurs — a craving for ice, chalk, or other non-food substances, as well as restless legs syndrome.

With a B12 deficiency, numbness and tingling in the limbs, balance disturbances, and changes in mood and memory may appear. These symptoms require attention, because neurological damage can be irreversible with prolonged deficiency.

Important: symptoms correlate poorly with the degree of anemia. A gradual decrease in hemoglobin is compensated by the body, so a person may have substantial anemia and feel only fatigue.

Which tests to take and how to read them

The basic panel includes a complete blood count with red-cell indices (MCV, MCH, RDW), ferritin, and C-reactive protein. If needed, serum iron, transferrin and its saturation, reticulocytes, vitamin B12, and folate are added.

Ferritin is the main indicator of iron stores. Low ferritin reliably points to iron deficiency. But ferritin is also an acute-phase protein, and against a background of inflammation or after exhausting exertion it can be falsely normal. That is precisely why it is assessed together with CRP.

For athletes, various threshold values of ferritin are discussed in the scientific literature, and there is no single generally accepted one. Interpretation should be left to a doctor, who will take into account sex, sport, symptoms, and the trend.

Practical rules for the blood draw: in the morning, on an empty stomach, after a rest day or light training, in a state of normal hydration. To assess the trend it is useful to take tests at the same time of the season and in a single laboratory.

Prevention through nutrition

The basis of prevention is sufficient energy availability and a varied diet. Heme iron from red meat, poultry, and fish is absorbed much better than non-heme iron from plant products. Legumes, dark leafy vegetables, whole grains, and fortified cereals are also sources of iron.

Vitamin C in the same meal enhances the absorption of non-heme iron. On the other hand, tea, coffee, calcium, and the phytates of bran reduce it. A simple tip is to drink tea or coffee between meals rather than during them.

• sources of heme iron several times a week (if the diet allows);
• legumes, dark leafy vegetables, and fortified products;
• vitamin C together with plant sources of iron;
• tea and coffee — between meals;
• B12 for vegans — mandatory.

Athletes should take into account the hepcidin effect of training: in studies, iron absorption was better in the morning and in the first hours after training than several hours after it. So iron-rich food should be eaten without delay after a morning session.

Vegans need vitamin B12 supplements — this is a standard recommendation. It is also useful for vegetarians and vegans to periodically monitor ferritin.

Iron supplements: a sensible approach

Iron supplements are an effective way to eliminate a deficiency, but taking them blindly is not advisable. An excess of iron can accumulate in the body, and in people with hereditary hemochromatosis this leads to damage of the liver, heart, and joints. So first — tests, then — a decision.

The study by Stoffel and colleagues showed that taking iron every other day may provide better fractional absorption than daily intake, because of the effect of each dose on hepcidin. This approach is today often discussed as a way to improve tolerability.

The side effects of oral preparations are nausea, constipation, abdominal pain, and dark stool. Their severity depends on the dose and form. Intravenous iron is used for medical indications, for example in cases of intolerance or impaired absorption, and only in medical facilities.

Iron supplements should be stored out of the reach of children: accidental iron poisoning in children can be fatal. This is a standard warning on the packaging of iron preparations.

When to see a doctor

It is worth seeing a doctor if for several weeks there persists unexplained fatigue, decreased endurance, shortness of breath, or dizziness, or if tests reveal lowered hemoglobin or ferritin.

Emergency help is needed in cases of fainting, chest pain, pronounced shortness of breath at rest, black tarry stool, or vomiting blood. These signs may indicate bleeding or severe anemia.

1. fainting, chest pain, shortness of breath at rest;
2. black stool or blood in the vomit;
3. anemia in men or postmenopausal women without a clear cause;
4. a combination of anemia with jaundice, bruising, or changes in other blood indicators.

Iron deficiency in men and postmenopausal women always requires a search for the cause, primarily the exclusion of hidden bleeding from the gastrointestinal tract and celiac disease. One cannot limit oneself to merely prescribing a supplement.

Jaundice, dark urine, an enlarged spleen, a simultaneous decrease of several blood indicators, or unexplained bruising are signs that require a consultation with a hematologist.

Editorial conclusions

Anemia can be detected early if you regularly take basic tests and interpret them correctly. For athletes, a single hemoglobin indicator is not enough: ferritin, CRP, and red-cell indices are needed.

Prevention is based on sufficient energy, a well-thought-out diet, and a sensible organization of meals with respect to training. Iron supplements are effective, but should be prescribed based on test results.

It is important not to limit oneself to treating an indicator: especially in men and postmenopausal women, iron deficiency may be the first sign of a serious illness.

We also recommend our materials on the causes of anemia in athletes, on interpreting ferritin, and on the nutrition of vegetarians in sport.

References

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3. World Health Organization. Haemoglobin concentrations for the diagnosis of anaemia and assessment of severity. Geneva: WHO; 2011 (WHO/NMH/NHD/MNM/11.1).
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