# Relative energy deficiency in sport: a cross-sectional study of nutritional, biochemical and hormonal profiles in Czech female endurance athletes at risk of low energy availability

## TL;DR

This study found that female endurance athletes are at higher risk of low energy availability, which affects their hormonal and nutritional health.

## Contribution

The study provides new insights into the prevalence and biochemical markers of RED-S in female endurance athletes using a multifactorial approach.

## Key findings

- Athletes had higher LEAF-Q scores and more menstrual issues compared to controls.
- Athletes with LEAF-Q ≥8 showed lower estradiol, progesterone, leptin, and phosphorus levels.
- They also had higher hepcidin and free T3 concentrations, indicating metabolic and hormonal disruptions.

## Abstract

Regular physical activity is associated with substantial health benefits, provided the body has sufficient energy sources. However, a long-term low-calorie intake can cause the syndrome of Relative Energy Deficiency in Sport (RED-S) with a significant health threat to athletes. Therefore, the objective of the current study was to evaluate markers of RED-S in a cohort of female athletes.

The study was carried out in a cohort of female endurance athletes (n = 23) and healthy female control subjects (n = 21) recruited from a total of 42 athletes and 45 controls who underwent the Low Energy Availability in Females Questionnaire (LEAF-Q) survey. Anthropometric, nutritional, and laboratory analyses were performed on study subjects.

A higher LEAF-Q score signifying low energy availability (LEA) was observed in athletes compared to controls (8 vs. 5, p < 0.005). Menstrual problems were significantly more common in athletes, with 33.3% of athletes having amenorrhea (p < 0.001). Compared to control women with LEAF-Q < 8, energy expenditure was higher (p < 0.001) in athletes with LEAF-Q ≥ 8, and athletes had a negative energy balance (90%) with a very low value of energy availability (24.3 kcal/kg FFM/day). Athletes with a LEAF-Q score ≥8 had lower serum concentrations of estradiol (p < 0.001), progesterone (p < 0.001), leptin (p < 0.001), white blood cells (p < 0.005) and phosphorus (p < 0.005). Furthermore, they had significantly higher concentrations of hepcidin (p < 0.05) and free T3 (p < 0.05).

LEA is prevalent in female endurance athletes, and its diagnosis deserves a multifactorial approach with anthropometric and nutritional analyses, and the use of a wider range of laboratory markers.