BIG Nutrition: Iron absorption after morning exercise


BIG Nutrition: Iron absorption after morning exercise

Iron is a key nutrient for athletes and deficiency in this nutrient is possible due to the increased demand in those who are active, may not consume enough, and/or have poor absorption of iron. A recent Sports Medicine Bulletin reported findings of a very small research study (16 people) examining morning or evening exercise and its impact on iron absorption and a hormone involved in iron absorption.

The questions in this very small study were:

  • Is a hormone, hepcidin, a regulator in iron absorption higher post-exercise?
  • Are there variations in the hormone level in the morning versus evening and in post-exercise versus a rested state?
  • Does exercise have an effect on absorption of iron from an iron rich meal?

The findings support that:

  • Hepcidin levels were higher in the post-exercise state than in the rested state.
  • While the hepcidin was higher after exercise, it was highest in the morning compared to the evening. The researchers hypothesize that there may be a variation in the hormone level because of circadian rhythms.
  • With higher levels of the hormone, the best absorption of iron came after a morning workout.

With all research, it is important to consider the context and strength of the evidence. With only 16 people, all trained athletes, 10 men and 6 women from Australia, these results may have limited applicability to other people. One other aspect is the potential risk. In this case, they tested an iron rich meal rather than supplements, so unless a person has a condition where iron intake is cautioned, it is low risk and may be helpful to consume an iron rich meal (eg, lean beef, lentils, spinach) after exercise, especially a morning workout, to promote iron absorption.

Happy and healthful eating,

Donna G. Pertel, MEd, RD, LDN

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