Anemia: prevention, diagnosis and when to see a doctor

Anemia rarely occurs suddenly: usually it is 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 really informative and when a drop in hemoglobin is a reason for an immediate visit to a doctor.

Symptoms worth paying attention to

Early signs of anemia are nonspecific: fatigue, decreased endurance, shortness of breath at usual loads, rapid heartbeat, headache, dizziness on standing up. 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. In pronounced iron deficiency, pica occurs - a craving for ice, chalk or other non-food substances - as well as restless legs syndrome.

With B12 deficiency, numbness and tingling in the limbs, balance disorders, mood and memory changes 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 can 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 necessary, serum iron, transferrin and its saturation, reticulocytes, vitamin B12 and folate are added.

Ferritin is the main indicator of iron stores. Low ferritin reliably indicates iron deficiency. But ferritin is also an acute-phase protein, and against a background of inflammation or after exhausting exertion it may be falsely normal. That is exactly 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 dynamics.

Practical sampling rules: in the morning, on an empty stomach, after a rest day or light training, in a state of normal hydration. To assess dynamics it is useful to take tests at the same time of the season and in the same 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 significantly better than non-heme iron from plant products. Legumes, dark leafy vegetables, whole-grain products and fortified cereals are also sources of iron.

Vitamin C in the same meal enhances the absorption of non-heme iron. In contrast, tea, coffee, calcium and bran phytates reduce it. A simple tip is to drink tea or coffee between meals, not during them.

• sources of heme iron several times a week (if the diet allows it);
• 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 later. Therefore 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 they should not be taken blindly. Excess iron can accumulate in the body, and in people with hereditary hemochromatosis this leads to damage to the liver, heart and joints. So first come tests, then a decision.

A study by Stoffel and co-authors showed that taking iron every other day can provide better fractional absorption than daily, due to the effect of each dose on hepcidin. This approach is now often discussed as a way to improve tolerability.

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

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

When to see a doctor

You should see a doctor if unexplained fatigue, reduced endurance, shortness of breath or dizziness persist for several weeks, or if tests reveal reduced hemoglobin or ferritin.

Emergency care is needed for fainting, chest pain, severe 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 vomit;
3. anemia in men or postmenopausal women without a clear cause;
4. a combination of anemia with jaundice, bruises or changes in other blood parameters.

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

Jaundice, dark urine, enlargement of the spleen, a simultaneous decrease in several blood parameters or unexplained bruises 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 value is not enough: ferritin, CRP and red cell indices are needed.

Prevention is based on sufficient energy, a thoughtful diet and sensible organization of meals relative to training. Iron supplements are effective but must 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 disease.

We also recommend our materials on the causes of anemia in athletes, on the interpretation of 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).
4. Sim M, Garvican-Lewis LA, Cox GR, et al. Iron considerations for the athlete: a narrative review. Eur J Appl Physiol. 2019;119(7):1463–1478.
5. Stoffel NU, Cercamondi CI, Brittenham G, et al. Iron absorption from oral iron supplements given on consecutive versus alternate days and as single morning doses versus twice-daily split dosing in iron-depleted women: two open-label, randomised controlled trials. Lancet Haematol. 2017;4(11):e524–e533.
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7. Mountjoy M, Ackerman KE, Bailey DM, et al. 2023 International Olympic Committee's (IOC) consensus statement on Relative Energy Deficiency in Sport (REDs). Br J Sports Med. 2023;57(17):1073–1097.