A Preliminary Study of Nutrients Related to the Risk of Relative Energy Deficiency in Sport (RED-S) in Top-Performing Female Amateur Triathletes: Results from a Nutritional Assessment

Abstract

Background/Objectives: As an endurance multi-sport race, triathlon places significant energy demands on athletes during performance and training. Insufficient energy intake from food can lead to low energy availability (LEA) and Relative Energy Deficiency in Sport (RED-S). We aimed to measure symptoms related to LEA, examine the risk of RED-S, and find how diet relates to the risk of RED-S in highly trained female amateur triathletes. Methods: Our sample was 20 top-performing female triathletes competing in Quarter Ironman (IM), Half IM, IM, or Double IM triathlons for 5.5 ± 2.5 y who were during the preparatory phase of training (training load 11 ± 3.76 h/week, a single workout 84 ± 25 min). Triathletes completed 3-day food diaries, training diaries, and the Low Energy Availability in Females Questionnaire (LEAF-Q). Exercise energy expenditure was estimated using wrist-worn activity trackers. To examine dietary patterns related to the first signs of LEA, predating RED-S, we created two groups: the L-LEA group (LEAF-Q score 0-5, no symptoms related to LEA, low risk of RED-S, n = 10) and the H-LEA group (LEAF-Q ≥ 6, at least one LEA-related symptom, high risk of RED-S, n = 10). Results: The risk of RED-S was prevalent in 30% of female triathletes, and 50% showed at least one symptom related to LEA. Macronutrient intake was similar in all participants, but triathletes from the H-LEA group tended to eat more plant-sourced protein and fiber. They consumed less saturated fatty acids but ingested more significant amounts of n-6 polyunsaturated fatty acids (PUFAn6). Conclusions: We conclude that foods higher in plant proteins, fiber, and PUFAn6 might predispose female triathletes to LEA by reducing the diet's energy density.

Keywords: PUFA; diet; endurance; energy intake; female athletes; fiber; plant protein; sports nutrition; triathlon.

Figure 1

Low Energy Availability in Females Questionnaire (LEAF-Q) scores in top-performing female amateur triathletes. Triathletes with LEAF-Q scores ≥ 8 were classified as at risk of Relative Energy Deficiency in Sport (RED-S). Triathletes who scored ≥ 6 and exhibited at least one symptom related to LEA were deemed at high risk of RED-S and assigned to the H-LEA group. Diet: LA, lacto-vegetarian; LO, lacto-ovo-vegetarian; OO, ovo-vegetarian; OV, omnivorous; PE, pescatarian.

Figure 2

Relative total energy expenditure (rTEE), relative energy intake (rEI), and relative energy deficit (rED) in female amateur triathletes. Relative energy deficit is shown in absolute values. L-LEA, low LEA (LEAF-Q score 0–5 pts); H-LEA, high LEA (LEAF-Q score ≥ 6 pts).

Figure 3

Energy intake from macronutrients. ECHO, energy intake from carbohydrates [%]; EPROT, energy intake from proteins [%]; EFAT, energy intake from fats [%]; LEAF-Q, Low Energy Availability in Females Questionnaire. All study participants are displayed in one radar plot with different colors allocated to various LEAF-Q scores: LEAF-Q score ≤ 2 pts (blue), LEAF-Q score 3–5 pts (green), LEAF-Q score 6–7 pts (orange), LEAF-Q score 8–10 pts (red), and LEAF-Q score ≥ 11 pts (dark red). Each polygon represents one participant.

Figure 4

Daily intake of fiber (fiber) [g/d], leucine (Leu) [g/d], valine (Val) [g/d], isoleucine (Ile) [g/d], proteins of animal origin (APROT) [g/kg/d], and proteins of plant origin (PPROT) [g/kg/d]. LEAF-Q, Low Energy Availability in Females Questionnaire. All study participants are displayed in one radar plot with different colors allocated to various LEAF-Q scores: LEAF-Q score ≤ 2 pts (blue), LEAF-Q score 3–5 pts (green), LEAF-Q score 6–7 pts (orange), LEAF-Q score 8–10 pts (red), and LEAF-Q score ≥ 11 pts (dark red). Each polygon represents one participant.

Figure 5

Daily intake of fiber [g/d], proteins of plant origin (PPROT) [g/d], and proteins of animal origin (APROT) [g/d]. L-LEA, low LEA (LEAF-Q score 0–5 pts); H-LEA, high LEA (LEAF-Q score ≥ 6 pts).

Figure 6

Daily intake of fat (FAT) [g/d], n-6 polyunsaturated fatty acids (PUFAn6) [g/d], n-3 polyunsaturated fatty acids (PUFAn3) [g/d], monounsaturated fatty acids (MUFA) [g/d], and saturated fatty acids (SFA) [g/d]. LEAF-Q, Low Energy Availability in Females Questionnaire. All study participants are displayed in one radar plot with different colors allocated to various LEAF-Q scores: LEAF-Q score ≤ 2 pts (blue), LEAF-Q score 3–5 pts (green), LEAF-Q score 6–7 pts (orange), LEAF-Q score 8–10 pts (red), and LEAF-Q score ≥ 11 pts (dark red). Each polygon represents one participant.

Figure 7

Daily intake of saturated fatty acids (SFA) [g/d], monounsaturated fatty acids (MUFA) [g/d], n-3 polyunsaturated fatty acids (PUFAn3) [g/d], and n-6 polyunsaturated fatty acids (PUFAn6) [g/d]. L-LEA, low LEA (LEA 0–5); H-LEA, high LEA (LEA ≥ 6).

Figure 8

Daily intake of fiber (fiber) [g/d], leucine (Leu) [g/d], valine (Val) [g/d], isoleucine (Ile) [g/d], proteins of animal origin (APROT) [g/kg/d], proteins of plant origin (PPROT) [g/kg/d], fat (FAT) [g/d], n-6 polyunsaturated fatty acids (PUFAn6) [g/d], n-3 polyunsaturated fatty acids (PUFAn3) [g/d], monounsaturated fatty acids (MUFA) [g/d], and saturated fatty acids (SFA) [g/d]. Two groups (L-LEA and H-LEA) are displayed in each radar plot with two different colors. L-LEA, low LEA (LEAF-Q score 0–5 pts); H-LEA, high LEA (LEAF-Q score ≥ 6 pts).