How and when do I use it?
- Physicians are guided by the following outline when considering the frequency of iron blood screening for athletes.2
- Early identification of compromised iron stores (in the IDNA phase) is important since it allows athletes to consider nutritional and supplementation options with their physician and/ or accredited sports dietitian to prevent progression to IDA.
Figure 1. Framework of considerations for the frequency of iron blood screening in athlete populations.
Image text
Considerations and frequency of iron blood screening for athletes
Variables to be considered.
- Minimum: serum ferritin, hemoglobin concentration, transferrin saturation.
- Desirable: Serum soluble transferrin receptor, hemoglobin mass, C-reactive protein.
Standardisation of blood collection.
- Time of day: Preferably in the morning.
- Hydration state: Hydrated preferably assessed by waking urinary specific gravity (<1.025).
- Low to moderate activity in the proceeding 24 hours, including no muscle-damaging exercise (e.g. eccentric) in 2-3 days prior.
- No signs of sickness or infection.
Annually
- No history of iron deficiency.
- No history of irregular/excessive menses or amenorrhea.
- No reports of fatigue after extended rest.
- Strength/power-based sports with minimal endurance component.
- No iron-related dietary restrictions.
- No evidence of low energy availability.
- No intention to undertake hypoxic training in the next 12 months.
- No underlying pathology (e.g. coeliac or Crohn’s disease).
Biannually
- Female.
- Previous history (≥24 months) of iron depletion (e.g. Stage 1).
- Previous history (≥24 months) of irregular/excessive menses.
- Intention to undertake high training loads especially in endurance and team-based sports.
- Minimal (or zero) reports of prolonged fatigue after extended rest.
- No iron-related dietary restrictions (e.g. non-vegetarian, non-vegan).
- No evidence of low energy availability.
- Intention to undertake hypoxic training in the next 12 months.
Quarterly
- Any recent history (<24 months) of iron depletion/deficiency (Stage 1, 2, or 3) irrespective of sex.
- Any evidence of irregular/excessive menses or amenorrhea.
- High training loads in endurance and team-based sports.
- Reporting prolonged fatigue/lethargy even after extended rest.
- Reduced work capacity during training.
- Unexplained poor athletic performance.
- Individuals restricting sources of dietary iron (e.g. vegetarian and vegan) or overall caloric intake.
- Any evidence of low energy availability.
- Intention to undertake hypoxic training in the next 6 months.
This figure has been adapted from Sim et. al.2
- Below is a framework to guide practitioners towards optimal treatment protocols for iron deficient athletes, diagnosed via haematological indices.1
- Iron supplements should only be taken under medical supervision as part of an integrated iron management program, which includes dietary assessment and enhancement of dietary iron intake.
- Current research suggests that a daily dose of 100 mg of elemental iron (or every second day if GI upset is present) for 8-12 weeks can significantly improve ferritin stores.3,4,5 This should be confirmed via a subsequent blood test.
- Consuming the oral iron supplement in the morning, as close to exercise as possible, may result in a greater level of iron absorption.6
Figure 2. Framework to guide practitioners towards optimal treatment protocols for iron deficient athletes, diagnosed via haematological indice
Image text
Athlete blood screening
[left hand side]
IDNA
- sFer <35 µg·L-1·
- [female symbol] [Hb] 120 – 155 g·L-1·
- [male symbol] [Hb] 135 – 175 g·L-1·
Oral iron supplementation (4-12 weeks)
- 100 mg oral iron (ferrous salt) daily in the morning If negative GI side-effects experienced
- 100 mg oral iron (ferrous salt) on alternate mornings If negative GI side-effects persist
- 60 mg (or tolerable dose) oral iron on alternate mornings
OR
- mg controlled release oral iron on alternate mornings
Athlete intolerant or not responding to oral iron treatment
[middle]
Dietary assessment/intervention with an accredited sports dietitian
[right]
IDA
- sFer <12 µg·L-1·
- [female symbol] [Hb] <120 g·L-1·
- [male symbol] [Hb] <135 g·L-1·
IV treatment
Note: Individual responses to IV treatment vary. Follow up blood screen at 1 & 6-months post-treatment recommended.
[key]
Key
- - - Medical professional’s discretion
This figure has been adapted from McCormick et. al.1
- The absorption of oral iron supplements is enhanced by consuming it with a source of vitamin C (~50-100 mg). This can be achieved by choosing a supplement in which Vitamin C is also provided, or by consuming it with an appropriate (e.g. citrus) fruit or juice. Factors that interfere with iron absorption such as calcium (dairy) and tannins (tea and coffee) should be avoided for an hour each side of the time of consumption of the supplement.
- Examples of both inhibitors and promoters of non-haem iron absorption1 are presented in Table 1
Table 1. Dietary factors that either enhance or inhibit iron absorption.
Inhibitors of non-haem iron absorption | Promotors of non-haem iron absorption | |||
|---|---|---|---|---|
Phytates | Found in whole-grain cereals, legumes, nuts and seeds | Vitamin C (ascorbic acid) | Aim 50+ mg. Found in citrus fruit (e.g. oranges, kiwifruit), broccoli, tomato, capsicum | |
Polyphenols/ phenolic compounds | Found in tea (herbal and non-herbal), coffee, red wine and chocolate (cocoa) | Carotenoids | Found in pumpkin, carrots, grapefruit and apricots | |
Calcium | Found in dairy products (e.g. yoghurt, milk, cheese) and multivitamin supplements | Fermented foods | Fermentation reduces the presence of phytates; e.g. sauerkraut, kimchi and miso | |
Other minerals | Zinc and manganese (compete for intestinal absorption) | Cooking your food | Reduces the phytates present in food |
- If an athlete is undertaking specific altitude training, a pre-training screen of iron status is advised. This should be done with enough time (i.e. 8-12 weeks prior) to allow correction of iron depletion (IDNA or IDA) to be achieved prior to the start of the altitude training program.
- Athletes who have ferritin levels of 50-100 μg·L-1 (i.e. just above the levels traditionally considered to represent iron depletion) might consider taking an oral iron supplement (~100 mg daily or alternate day, as above) for two weeks prior to the start of altitude training and throughout the training program, since there is evidence that this supports greater adaptation to the altitude stimulus. Note: IV iron supplementation does not appear to improve the benefits of altitude adaptation more than oral supplementation.4,7,8