Table 2 Comparison of effects of dietary iron treatment methods on iron status in female athletes

Tsalis et al. [42]

21 male and 21 female swimmers, iron-repleted (sFer >30 μg/L, Hb > 12 g/dl) aged 12–17 years BMI 20

Study design:

- NS differences in iron status and exercise performance among 3 groups.

Supplementation and dietary randomised control trial

6-month intervention

A: Fe supplement (47 mg/d)

B: diet rich in Fe (26 mg/d)

C: placebo

Dietary assessment:

Records of daily food intake

Performance assessment:

Swimming tests

Ishizaki et al. [43]

8 collegiate rhythmic gymnasts, aged 18–19 years, BMI 19.7, sFer <20 μg/L

Study design:

- SIG increased sFer and δ-ALAD activity (enzyme responsible for RBC turnover) after diet intervention.

Dietary intervention

4-weeks intervention in 2 years cohorts:

−1^st year self-selected diets

- No effect on other parameters of iron status.

−2^nd year fixed diet for 4 weeks (15 mg Fe/day)

Dietary assessment:

3-day FD 3 times in 1^st / 2^nd year at baseline, 4, 8 weeks

Performance assessment:

None

Lyle et al. [11]

60 exercising (2.3–2.5 days/week) females, previously sedentary, iron-repleted (sFer >20 μg/L, Hb > 12 g/dl) aged 18–19 years

Study design:

- Moderate aerobic exercise compromised iron status.

Supplementation and dietary randomised control trial

12-week intervention

- Meat diet was more effective in protecting Hb and iron status than were iron supplements.

A: Fe 50 mg + low diet Fe

B: Fe 10 mg + low diet Fe

C: placebo

D: meat diet (18 mg Fe)

Dietary assessment:

7-day FD

Performance assessment:

Walking and treadmill tests

Anschuetz et al. [12]

12 male and 5 female collegiate middle distance runners and 6 male and 2 female non-running controls, aged 18–24 years, sFer <30 μg/L

Study design:

- sFer SIG greater in MHIA than LMIA group.

Dietary advice counselling intervention

4-week dietary advice counselling intervention in LMIA group only

- SIG correlations between absorbable dietary Fe and sFer, sFe, TIBC and Hb.

LMIA: low/medium Fe availability diet

- No significant difference in iron status indices between LMIA and MHIA groups post-intervention

MHIA: medium/high Fe availability diet

C: control

Dietary assessment:

3-day FD

Performance assessment:

None

Burke et al. [13]

14 male and 14 female collegiate cross country runners, aged 18–24 years, sFer >60 μg/L

Study design:

- NS improvements in haematocrit and TIBC in intervention group females.

Dietary randomised control trial

8-week intervention

- No differences between the groups in other parameters of iron status.

IG: 9 oz lean beef/week

- No difference in VO_2max changes between the groups.

C: control group

Dietary assessment:

3-day FD

Performance assessment:

Treadmill tests

Alaunyte et al. [1]

11 female runners, recruited from running clubs, aged 20–44 years, BMI 23, sFer >30 μg/L

Study design:

- NS improvements in iron

Dietary intervention

6-week intervention (18.5 mg Fe/d)

- SIG correlations between ↑ dietary iron and ↑ sFer (r = 0.8, P < 0.05).

Dietary assessment:

Multiple 24-h recalls

Performance assessment:

None