Состояние обмена железа при повышенных физических нагрузках

Представлен обзор мировой литературы, посвященной изучению состояния обмена железа в организме спортсменов на основании оценки рутинных показателей. Проведена оценка обеспеченности организма спортсменов железом в существующих работах двумя способами: 1) определение концентрации ферритина и, реже, других показателей, таких как насыщение трансферрина и сывороточное железо, и их сравнение с референтными (или пограничными) величинами; 2) сравнительный анализ маркеров гомеостаза железа у спортсменов и контрольной группы. Установлено, что большинство спортсменов характеризуется истощением запасов железа, в то же время в ряде работ продемонстрировано, что распространенность железодефицита у спортсменов существенно не отличается от фонового уровня в популяции. Рассмотрена взаимосвязь маркеров обмена железа в организме с физиологическими параметрами спортсменов. Рекомендовано сочетание нескольких способов мониторинга обмена железа, включая как прямое определение железа в индикаторных биосубстратах, так и оценку концентрации железосодержащих белков.

The iron metabolism status in the athletes

The intense physical activity significantly impacts iron metabolism of the organism. Consequently, the athletes and persons exposed to high physical load are characterized by a high rate of the iron metabolism disturbances. Therefore, the objective of the present study is the review of the world scholarly published articles devoted to the investigation of the iron metabolism in the athletes based of routine markers assessment. Assessment of iron status in athletes in the articles was performed using two approaches: 1) analysis of ferritin concentrations and, less frequently other markers like transferrin saturation and serum iron, and their comparison to the reference (or cut-off) values; 2) comparative analysis of iron metabolism markers in comparison with the control values. Using various cut-offs for serum ferritin it has been revealed that the majority of athletes are characterized by low iron stores. At the same time, a number of studies demonstrated that the incidence of iron deficiency in athletes is not different from the background levels in the population. A comparative analysis of iron status in the athletes and control values provided more heterogenous data. In particular, despite the fact that the majority of studies has indicated the presence of iron deficiency, a significant number of studies demonstrated the absence of significant group difference as compared to the controls, and, moreover, higher values of iron status as compared to the control group. Review of studies dealing with iron status assessment using chemical analysis of hair, saliva and other substrates also revealed multidirectional trends. The association of iron status with physiological parameters of athletes is discussed. Despite being rather contradictory, the existing data indicate the tendency to iron deficiency in the organism of athletes. At least partially, the observed contradictions may be mediated by the use of various markers and substrates. Therefore, the combined analysis of the different methods for iron status monitoring, including a chemical analysis of the iron in various substrates and assessment of iron-binding proteins concentration is recommended. At the same time, the decision on the necessity of iron supplementation should be based on the results of personalized diagnosis, taking into account the possibility of iron overload and subsequent toxicity.