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Mayo Clinic Minute: Female athletes may need more ironIron supplementation in athletes -
Eating a balanced diet, staying active, and maintaining good sleep hygiene are enough for most of us to get by and stay healthy, but the same is not always true for athletes.
For those who put their body through more extreme physical activity and demand peak performance, intense daily exercise requires an increased need of various nutrients, such as vitamins, minerals and fluids. Adding an iron supplement may promote faster recovery, and help athletes bounce back from the effects of daily training, as well as muscle or bone injury.
According to the National Heart, Lung, and Blood Institute , endurance athletes are at risk for iron deficiency. In addition, the NIH reports a negative energy balance is common in endurance athletes, and those participating in weight-making sports, like wrestling, boxing or MMA, as well as aesthetic activities, such as gymnastics, dancing or figure skating.
Athletes who are large in stature might also find it difficult to achieve balanced energy, especially during high-volume training phases. Further complicating things is that high-intensity training can reduce appetite , and hectic travel schedules and poor food availability while traveling for competitions might mean that some athletes have a hard time meeting their energy requirements, which is a big setback.
An important factor in maintaining energy supply is getting enough iron. Hemoglobin carries oxygen from the lungs throughout the rest of the body. It also makes myoglobin, which provides oxygen specifically to the muscles, and iron is also in the creation of some hormones.
Iron comes in two forms in the food we eat: heme iron animal-derived and non-heme iron plant-derived. Iron deficiency progresses in three stages [ 21 ].
Firstly, iron stores in reticuloendothelial cells of the liver, spleen and bone marrow are depleted, which is observed as a fall in serum ferritin and is referred to as iron storage depletion.
The second stage is represented by erythropoiesis, where transport iron is decreased and hence, iron supply to the cells is reduced. This stage is manifested as low serum iron, increased total binding capacity and a decrease in transferrin saturation.
In the last stage of iron deficiency, haemoglobin synthesis falls due to insufficient iron supply, resulting in anaemia [ 21 ]. It is generally agreed that serum ferritin sFer is the index of iron stores in healthy subjects [ 15 ].
Plasma serum ferritin levels are strongly correlated with iron stores in the bone marrow [ 22 ], hence, low levels of serum ferritin indicate latent iron deficiency. Due to this wide inter-individual variation, the lower limit of serum ferritin for indication of latent iron deficiency in female athletes is not well established.
The reference nutrient intake RNI for adult females in the UK is Whilst additional iron is recommended for pregnant and lactating females, an increased iron allowance is not an official recommendation for female athletes.
Although increased loss of several minerals, including iron, from the body during exercise has been well established, there is limited evidence of adverse effect on the body stores [ 27 ]. If this suggestion was to be followed, a daily intake of 10 mg of iron would be added to the UK recommended value of Some literature suggests that although female athletes generally meet their energy and micronutrient needs, they do not achieve the recommended intake of dietary iron [ 1 , 29 ], whilst others report adequate intakes for this population [ 30 ].
Furthermore whether the lack of iron in the diet contributes to lower iron status in this population is opened to further debate. In addition, both studies found that the intakes for most other nutrients, including daily energy, protein and Vitamin C were near recommended levels, except for iron, indicating that poor dietary iron intake might contribute to compromised iron status in this population.
This is in agreement with several other cross-sectional studies investigating the influence of dietary iron sources in female runners [ 2 , 31 , 32 ]. In a study carried out by Nuviala et al. Hassapidou and Manstrantoni [ 2 ] observed similar iron intakes of Koehler et al.
The study indicated that low serum ferritin levels were associated with lower dietary iron density mg per kcal but not total dietary iron intake. Some researchers have indicated that dietary iron intake in female athletes is similar to that of general population. In a large cross-sectional study by Pate et al.
In addition, dietary iron intake was associated with low serum ferritin levels in both groups. Supporting evidence was provided by a study of 40 female runners and 40 matched inactive counterparts [ 35 ], which showed that although the mean iron intake was similar in both groups athletes Woolf et al.
The presence of iron deficiency in physically active females and endurance athletes as a result of intensive training regimens and competition has been a topic of considerable attention over the last few decades.
This is due to notably high prevalence of latent iron deficiency seen in female athletes which in some cases is reported to be more than twice the level reported in their sedentary counterparts.
Table 1 summarises the findings of studies detailing the prevalence of latent iron deficiency in female athletes. The most convincing evidence highlighting the effects of exercise on iron status and the risk of iron deficiency is presented by Pate et al.
Furthermore, serum ferritin concentrations showed a significant negative correlation with running activity. Supporting evidence was provided by the following studies [ 1 , 30 , 33 , 36 , 37 ]. Researchers reported similar or even higher iron depletion levels in populations of physically active females, recreational female runners and elite female athletes.
Contrary findings were reported by the subsequent studies [ 38 , 39 ]. Di Santolo et al. The study did however report a two to threefold lower iron status indices in non-professional female athletes compared to inactive controls. Ostojic and Ahmetovic [ 39 ] reported similar iron depletion levels in female elite athletes but only found a weak association between training duration and serum ferritin levels.
A large cross-sectional study of female athletes and male athletes investigated haematological indices according to the predominant energy system required in difference sports [ 40 ]. The authors reported that female athletes who participate in sports which require mixed sources of energy supply i.
anaerobic and aerobic , such as rowing, volleyball, handball and some swimming and track and field sports, had the highest risk of iron deficiency compared to predominantly aerobic distance running, triathlon, tennis, cross-country skiing, road cycling or anaerobic sprinting, swimming, alpine skiing sports.
The most plausible explanation for this observation was suggested to be the adaptive responses in muscle tissue which is subjected to a greater need for oxygen in aerobic activities. This notion is also supported by other researchers [ 41 ] who looked at the association between iron status and exercise performance in female rowers at the beginning of a training season.
As expected, there were differences in exercise performance measurements, including VO 2peak , lactate concentration and time trial between female rowers with normal iron status and those who were deficient.
Studies using dietary iron treatment approach rather than pharmaceutical iron supplementation in female athletes are scarce. The summary of diet modification studies is presented in Table 2.
A longitudinal study showed no differences in iron status or swimming performance between an iron-rich diet and free choice diet in swimmers during a 6-month period [ 42 ].
Other dietary intervention studies have demonstrated more positive effects on iron status in female athletes. A four week iron-rich diet, which provided The study however did not assess their performance during the trial and hence, no conclusions can be drawn as to any possible effects on exercise performance.
A study by Lyle et al. Furthermore, the dietary intervention group showed the greatest improvements in exercise performance highlighting the possibility that dietary iron may play a role during exercise adaptation.
A dietary counselling intervention study conducted by Anschuetz et al. Nevertheless, the authors suggested that the diet composition, in particular the presence of enhancers of non-haem iron absorption, has a significant influence on iron absorption in this population.
The importance of iron bioavailability in dietary intervention was also studied by other researchers, who investigated the effects of the addition of lean beef to the diets of distance runners, during a competitive season [ 13 ]. The authors reported no significant differences between the intervention and control groups in iron parameters during a period of 8 weeks.
In fact, some of the iron status indices were found to have decreased in both groups, which may have been due to their intensive training regimens. The most recent study investigating iron status in female athletes used dietary intervention, incorporating a novel and naturally iron-rich Teff bread into the daily diets of female runners [ 1 ].
A six week dietary intervention, which provided The authors did however report significant correlations between the increase in dietary iron intake and changes in serum ferritin concentration. In addition, inadequate dietary iron intake and in particular the level of absorbable and bioavailable iron in the diet, may further contribute to depletion of stored iron.
Practical considerations for the maintenance or improvement of iron in female athletes should incorporate dietary modifications centred on healthy eating practices with particular focus on increasing total dietary iron, especially haem-iron intake, and improving iron bioavailability by altering meal composition.
For instance, iron-rich foods can be consumed with fruit and vegetables, enhancing iron absorption due to the presence of higher levels of Vitamin C.
Similarly, the intake of iron absorption inhibitors such as tannins in tea or coffee or calcium in milk, can be decreased or at least avoided in the same meal. To conclude, the majority of research studies support the hypothesis of the beneficial effect of dietary iron interventions on the balance of iron in iron-depleted female athletes.
However, the direct impact on exercise performance among female athletes is unclear. Nevertheless, there seems to be evidence that dietary iron interventions may assist in maintaining iron status in female athletes, especially during intensive training and competition regimens.
Alaunyte I, Stojceska V, Plunkett A, Derbyshire E. Dietary iron intervention using a staple food product for improvement of iron status in female runners.
J Int Soc Sports Nutr. Article PubMed Central PubMed Google Scholar. Hassapidou MN, Manstrantoni A. Dietary intakes of elite female athletes in Greece.
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McClung JP, Gaffney-Stomberg E, Lee JJ. Female athletes: a population at risk of vitamin and mineral deficiencies affecting health and performance.
J Trace Elem Med Biol. Article CAS PubMed Google Scholar. Burden RJ, Morton K, Richards T, Whyte GP, Pedlar CR. Is iron treatment beneficial in, iron-deficient but non-anaemic IDNA endurance athletes? A meta-analysis. Br J Sports Med. Google Scholar. Zimmermann MB, Hurrell R. Nutritional iron deficiency.
Mettler S, Zimmermann MB. Iron excess in recreational marathon runners. Eur J Clin Nutr. Burke LM, Millet GE, Tarnopolsky MA. Nutrition for distance events. J Sports Sci. Article Google Scholar. Hinton PS. Iron and the endurance athlete. Appl Physiol Nutr Metab.
Gera T, Sachdev HS, Boy E. Effect of iron-fortified foods on hematologic and biological outcomes: systematic review of randomized controlled trials. Am J Clin Nutr. Lyle RM, Weaver CM, Sedlock DA, Rajaram S, Martin B, Melby CL.
Iron status in exercising women - the effect of oral iron therapy vs increased consumption of muscle foods. CAS PubMed Google Scholar. For the best experience on this site and added security, please update to a modern browser. Iron is an essential mineral that assists in the transport of oxygen from the lungs to the rest of the body.
We need sufficient oxygen transport to enable our muscles to execute work. Iron is especially important for athletes due to the high work demands placed on their muscles during training and competition. The body gets iron through the food we consume.
An absence of iron-rich foods in the diet can lead to iron deficiency anaemia. Symptoms of iron deficiency anaemia include fatigue, pale skin, reduced exercise capacity and frequent illness.
You may also experience this from low energy availability or inadequate sleep so its useful to have a blood test done to determine if there is a deficiency. A blood test will consider 3 main areas of iron in the body, ferritin which is how iron is stored, trans ferritin which is how iron is transported and the total amount of iron as mineral in your body.
There are two different forms of dietary iron.
UPDATED: January 26, Athltes is an aupplementation Iron supplementation in athletes that assists in the transport Age-defying vegetables oxygen from the lungs to Natural skin remedies rest of the body, allowing muscles to work. Supplementatipn such, iron is especially important for athletes with increased Dental care for seniors Iron supplementation in athletes their muscles during training supplementation competition. Iron supplements are also used to address iron deficiency, but like all supplements, there is some level of risk for consumers. Yes, athletes may use oral iron pills, chews, and liquids without the need for a Therapeutic Use Exemption TUE. Iron pills, chews, and liquids taken by mouth are permitted, and there are numerous prescription products and over-the-counter medications. However, if an athlete chooses to use a dietary supplement for iron as opposed to a prescription or over-the-counter medication with a Drug Facts panel on the labelthey assume all the risks inherent to the supplement industry. Trained athletes and active clients are monitoring and tracking just about Atthletes these days. Athletew athletes track daily macronutrientsa critical piece of performance. This ensures they are providing adequate fuel to support their activity levels. However, one factor not typically tracked is micronutrient consumption. Athletes may be falling short on these critical nutrients.
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