*Review* **Iron Metabolism: Interactions with Energy and Carbohydrate Availability**

#### **Alannah K. A. McKay 1,\*, David B. Pyne 2, Louise M. Burke 1 and Peter Peeling 3,4**



 **\*** Correspondence: alannah.mckay@acu.edu.au

Received: 9 November 2020; Accepted: 27 November 2020; Published: 30 November 2020

**Abstract:** The provision or restriction of select nutrients in an athlete's diet can elicit a variety of changes in fuel utilization, training adaptation, and performance outcomes. Furthermore, nutrient availability can also influence athlete health, with one key system of interest being iron metabolism. The aim of this review was to synthesize the current evidence examining the impact of dietary manipulations on the iron regulatory response to exercise. Specifically, we assessed the impact of both acute and chronic carbohydrate (CHO) restriction on iron metabolism, with relevance to contemporary sports nutrition approaches, including models of periodized CHO availability and ketogenic low CHO high fat diets. Additionally, we reviewed the current evidence linking poor iron status and altered hepcidin activity with low energy availability in athletes. A cohesive understanding of these interactions guides nutritional recommendations for athletes struggling to maintain healthy iron stores, and highlights future directions and knowledge gaps specific to elite athletes.

**Keywords:** carbohydrate; low energy availability; RED-S;iron deficiency; ketogenic diets; hepcidin; exercise
