Dietary assessment of elite orienteering athletes

Abstract

Orienteering is an endurance sport requiring prolonged aerobic effort and high cognitive load, and adequate nutrition is essential to optimise performance, recovery, and long-term health. This cross-sectional study characterised dietary intake in Elite Orienteering Athletes (EOAs) and compared macronutrient and micronutrient intakes with current sports nutrition recommendations. Twenty EOAs (eight males and 12 females) were assessed during the orienteering competition “35° Trofeo Internacional Murcia Costa Cálida” in Spain. Dietary intake was recorded using a four-day weighed food record, including solid and liquid consumption, and compared with Dietary Reference Intakes (DRIs). Nutritional adequacy was expressed as the prevalence of athletes meeting DRIs (95% CI, Wilson method). Mean daily energy intake was 2134 ± 715 kcal/day, with only 5% of athletes meeting the recommended intake. Carbohydrate intake was below recommendations (42.5 ± 6.5% TEI), whereas protein (22.5 ± 15.0% TEI) and fat (37.9 ± 6.0% TEI) were consumed in excess. Calcium and zinc intakes were below DRIs, while phosphorus and sodium exceeded recommended values. Vitamin intakes were generally adequate, although vitamin D intake was insufficient, with only 30% of athletes meeting the DRI. These findings indicate notable nutritional imbalances among EOAs and highlight the need for individualised nutritional strategies to improve energy and carbohydrate availability and optimise key micronutrients to support performance and health.

Supplementary Information

The online version contains supplementary material available at 10.1038/s41598-026-45581-3.

Introduction

Nutrition is determinant of endurance performance, influencing acute exercise capacity, recovery, and longer-term training adaptations¹. To optimise these outcomes, athletes are encouraged to adopt evidence-based nutritional strategies tailored to their individual characteristics and the specific demands of their sport². For athletes with high physical activity levels (PAL), the position stand jointly issued by the American College of Sports Medicine (ACSM), the Academy of Nutrition and Dietetics (AND), and the Dietitians of Canada (DC) recommends carbohydrate and protein intakes above Dietary Reference Intakes (DRIs), which were originally established to define safe and adequate intake ranges for the general population³. These guidelines emphasise that athletes, particularly those at risk of low energy availability, should meet or exceed DRIs for selected micronutrients such as vitamin D, calcium, and iron in order to support energy metabolism, bone health, and recovery⁴.

Macronutrients, including carbohydrates, proteins, and fats, are fundamental to athletic nutrition. Sufficient carbohydrate intake is required to sustain energy production during training and competition and to restore muscle glycogen stores, whereas protein is required for muscle repair and adaptation; however, very high protein intake may displace carbohydrate and thereby compromise glycogen availability^5–7. Dietary fats support sustained energy supply, hormone synthesis, and overall health, with higher intakes of monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids (PUFAs) generally associated with cardiovascular and anti-inflammatory benefits that may favour recovery and endurance performance⁵. In contrast, saturated fatty acid (SFA) intake should be limited to < 10% of total energy intake (TEI) because of its adverse long-term health effects⁸. Dietary fibre also requires intentional planning in athletes, as intake may need to be adjusted according to gastrointestinal tolerance and body composition goals. In addition, fibre contributes to a healthy gut microbiome, intestinal barrier function, and short-chain fatty acid production⁹.

In addition to macronutrients, several micronutrients are vital for endurance athletes. Calcium and vitamin D are essential for bone health, prevention of stress fractures, and optimal muscle function, while iron and folate support haemoglobin synthesis, oxygen transport, and erythropoiesis, which are particularly important given the higher risk of iron deficiency in endurance athletes^6,10–12. Zinc and magnesium contribute to immune function, muscle contraction, and energy metabolism, and inadequate intakes may impair recovery and performance^6,13. Vitamins A, C, and E, together with B-group vitamins (B1, B2, B3, B6, B12), play central roles in antioxidant defence, carbohydrate and oxidative metabolism, and neurotransmitter synthesis, thereby supporting energy production, limiting exercise-induced oxidative damage, and promoting post-exercise recovery^12,14. Ensuring that endurance athletes achieve at least recommended intakes of these key micronutrients is therefore important both for health and for sustaining high training loads¹⁵.

Orienteering athletes (OAs) of the discipline Foot Orienteering (FootO), considered a form of cross-country running that combines prolonged aerobic effort with repeated bursts of higher-intensity activity and technical demands related to navigation and terrain¹⁶. This combination results in high energy expenditure and substantial stress on both the aerobic and anaerobic energy systems. Recent studies in orienteers have reported high weekly training volumes and energy expenditure, and have described predominantly ectomorphic or balanced mesomorphic somatotypes, suggesting a lean physique compatible with endurance performance^17–19. However, these studies have focused mainly on training load, energy expenditure, and body composition, and have provided little detail on whether OAs’ dietary intake aligns with current sports nutrition recommendations.

Evidence from a scoping review suggests that many athletes have suboptimal awareness of appropriate nutrient intakes and sports-specific dietary recommendations, which may lead to macronutrient inadequacies, increased fatigue, higher injury risk, and delayed recovery²⁰. A systematic review²¹ of dietary intake in athletes reported wide ranges for protein [1.1 to 3.4 g/kg body weight (BW)/day] and carbohydrate (2.4 to 4.6 g/kg BW/day) intake, with recommended ranges of 1.2 to 2.0 g/kg BW/day for protein and 3 to 12 g/kg BW/day for carbohydrate in sports nutrition guidelines²¹. Reported saturated fat intakes often approached or exceeded the recommended < 10% of total energy intake, whereas fibre intake typically ranged from 15 g to 45.8 g/day and fat intake from 0.9 to 1.6 g/kg BW/day. Intakes of sodium, calcium, potassium, and zinc also varied widely and were frequently below recommended levels²¹. Despite these data for athletes in general, it remains unclear whether Elite Orienteering athletes (EOAs) achieve age-specific DRIs and sports nutrition guidelines for macro- and micronutrients, given the unique energetic and technical demands of their sport.

The purpose of this study was to characterise dietary intake in EOAs and to compare their macronutrient and micronutrient intakes with current sports nutrition recommendations. We hypothesised that, while EOAs would meet age-specific DRIs, their carbohydrate and protein intakes would fall short of guideline values recommended for athletes engaged in high-volume endurance training.

Methods

Study settings and ethical principles

The study was conducted in accordance with the Declaration of Helsinki and was approved by the Ethics Committees of the Wroclaw University of Health and Sport Sciences (approval no. 19/2021) and of the Faculty of Human Kinetics, University of Lisbon (approval no. 13/2022). All participants provided written informed consent. This single cross-sectional study was conducted during the “35° Trofeo Internacional Murcia Costa Cálida”, Spain, organised by the Spanish Orienteering Federation (FEDO) (Federación Española de Orientación) and Orienteering Federation of the Region of Murcia (F.O.R.M.) (Federación de Orientación de la Región de Murcia), which took place from 25 to 26 February 2023 in Cehegín, Region of Murcia, Spain. The competition was an International Orienteering Federation (IOF) World Ranking Event (WRE), valid for international ranking, in which only the world’s best orienteers competed in the elite category (athletes must be included in this ranking to participate). The sample consisted of eight males (age = 23.75 ± 3.45 years) and 12 females (age = 25.56 ± 4.48 years), and was selected as a convenience sample of EOAs of different nationalities who were available during the event. The main inclusion criteria for OAs were set as follows: (1) valid license in IOF¹ or national federation license; (2) being in the age group of 18 to 65 years; and (3) without metabolic disease or any disease that could affect body fat and not having taken hormone treatment or corticoids in the three months prior to the study, except for contraceptives. Body weight was measured using a scale to the nearest 0.1 kg (Seca, model: 7601419004; Seca Gmbh & Co. KG, Hamburg, Germany) and height was measured using a stadiometer to the nearest 0.1 cm (Seca, model 2131721009; Seca Gmbh & Co. KG, Hamburg, Germany). Further details regarding the processes adopted for anthropometric assessment are provided in Silva et al.¹⁷ and Esteve-Ibáñez et al.¹⁸. Sociodemographic data and dietary history were collected through manual completion and subsequently sent to the researchers via email within two weeks.

Sample size estimation

The sample size (n) was calculated according to the Wilcoxon test for paired samples performed in G*Power version 3.1 software, with Cohen’s d = 0.8, a large effect size, expected by the hypothesis of an intake greater than the DRI, alpha = 0.05, and power (beta) = 0.9. In this case, the necessary sample size was N = 20. The same calculation conducted for the paired t-test yielded a sample size of N = 18.4.

Procedures

A dietary history was obtained using a four-day food record based on the food weighing method, which included both solid and liquid intake. One of the recorded days was a weekend day (Saturday or Sunday). This period was considered adequate to obtain sufficient information on orienteers’ usual dietary intake, minimising the risk of bias associated with selecting only one day per week, as described by Ortega et al.²². In these diaries, athletes recorded the number of meals, the amount of food, the ingredients used, and the preparation methods for each dish. To facilitate this task, information on the weight of each portion and the most common household measurements, standardised by the Spanish Society of Community Nutrition and Healthy Guide (SENC), was provided²³. This method facilitates maximum accuracy in estimating the weight and volume of food consumed. Based on this information, a nutritional intake analysis was done using the EasyDiet@ software developed by the Spanish Academy of Nutrition and Dietetics (AEND). The program allows users to input the quantities of food consumed and performs a nutritional analysis, providing values for both macronutrients and micronutrients. The percentage distribution of DRI for macronutrients and micronutrients was based on the nutritional objectives for the Spanish population established in the consensus guidelines of the Spanish Society of Community Nutrition (SENC) and the Spanish Agency for Food Safety and Nutrition (AESAN)^23,24.

Statistical analysis

The relative percentage variation from the DRI was calculated for each nutrient as (intake − DRI)/DRI×100. This metric was utilized as the primary variable for inferential testing and as an unstandardized measure of effect size to quantify the clinical magnitude of nutritional gaps or excesses. Normality was assessed using the Shapiro-Wilk test. Due to the small sample size and the presence of skewed distributions and dietary outliers, descriptive results are reported as Mean ± SD and Median [Q1–Q3] to ensure a robust characterization of the data.

Differences between nutrient intakes and the constant DRI values were assessed by applying the Wilcoxon signed-rank test directly to the relative variation scores, testing for significant departures from a zero-median. Comparisons between sexes were performed using two-sided independent samples t-tests or Mann-Whitney U tests, as appropriate. To control for the inflated Type I error rate arising from multiple testing across dozens of nutrients, all p-values were adjusted using the Benjamini-Hochberg False Discovery Rate (FDR) procedure.

Nutritional adequacy was further evaluated by calculating the prevalence of athletes meeting the recommendations, with 95% confidence intervals (CI) estimated using the Wilson score method. This method was chosen for its reliable coverage in small samples and proportions near the boundaries (0 or 1). Statistical significance was set at an adjusted p < 0.05. All analyses were conducted using R Statistical Software 3.6.3 (R Core Team, 2020).

Results

This section presents the findings from the dietary‑nutritional assessment of the EOAs participating in the study (N = 20; eight males: age = 23.75 ± 3.45 years; height = 178.21 ± 5.87 cm; weight = 65.53 ± 6.11 kg and 12 females: age = 25.56 ± 4.48 years; height = 168.22 ± 5.95 cm; weight = 60.12 ± 7.84 kg). Nutrient adequacy was evaluated by comparing observed intakes with sex‑specific Dietary Reference Intake (DRI) values. In the subsections that follow, nutrient intakes are reported according to the analytical framework described in the Statistical Analysis section, which includes adequacy expressed as the percentage of athletes meeting DRI values with 95% confidence intervals, the median intake relative to the DRI, and the relative percentage deviation from the DRI.

Mean daily energy intake for the overall sample was 2134 ± 715 kcal/day (females: 2004 ± 726 kcal; males: 2352 ± 583 kcal), with males not meeting the lower bound of their sex‑specific DRI range (Table 1). Only 5% of athletes met the recommended energy intake (95% CI: 0.3–23.6%). The negative relative‑variation value (− 20.7%, IQR 45.8) further indicates that energy intake in the group fell below the recommended DRI. As illustrated in Fig. 1, both sexes exhibited intakes below recommended levels, with particularly insufficient adequacy among male athletes.

Table 1.

Daily energy and macronutrient intake in elite orienteering athletes by sex and overall, compared with Dietary Reference Intakes (DRIs).

Nutrients	DRI	Female	Male	All Mean ± SD Median [Q1–Q3]	% meeting DRI (IC 95%)	Relative variation from DRI (%) Median (IQR)	p–value (FDR adjusted)
Energy (Kcal)	F: [2075–2300] M: [2700–3000]	2005 ± 726	2352 ± 583	2144 ± 679 2063 [1665–2713]	5 (0.3–23.6)	-20.7 (45.8)	0.088
Carbohydrates (%)	[45–60]	43.0 ± 6.2	41.7 ± 7.2	42.5 ± 6.5 43.3 [39.0–45.7]	30 (14.6–51.9)	-17.5 (12.6)	< 0.001***
Proteins (%)	[10–15]	24.5 ± 19.0	19.5 ± 5.2	22.5 ± 15.0 18.6 [16.8–20.9]	20 (8.1–41.6)	49.0 (32.6)	< 0.001***
Lipids (%)	[20–35]	37.4 ± 6.9	38.8 ± 4.7	37.9 ± 6.0 38.1 [32.8–40.7]	30 (14.6–51.9)	38.6 (28.7)	< 0.001***
SFA (%)	≤ 10	30.0 ± 7.3	29.7 ± 8.2	29.9 ± 7.5 30.4 [25.8–34.2]	0 (0.0–16.1)	204.0 (83.7)	< 0.001***
MUFAs (%)	≤ 20	36.7 ± 5.7	37.5 ± 4.3	37.0 ± 5.1 38.0 [33.7–40.0]	0 (0.0–16.1)	90.2 (31.6)	< 0.001***
PUFAs (%)	≤ 5	24.1 ± 8.5	22.8 ± 7.4	23.6 ± 7.9 22.7 [18.3–29.9]	0 (0.0–16.1)	354.2 (231.4)	< 0.001***
Cholesterol (mg)	< 300	309 ± 150	409 ± 127	349 ± 147 356 [233–425]	40 (21.9–61.3)	18.8 (64.0)	0.297
Fibre (gr)	25	31.8 ± 15.4	31.0 ± 11.7	31.5 ± 13.7 27.4 [22.7–34.9]	55 (34.2–74.1)	9.6 (49.0)	0.234

Data are presented as mean ± standard deviation (SD) and median [Q1–Q3]. The percentage of athletes meeting Dietary Reference Intakes (DRIs) is shown with 95% confidence intervals (Wilson method). Relative variation from DRIs was calculated as (intake − DRI)/DRI × 100 and is presented as median (interquartile range, IQR). P- values refer to differences from DRIs tested using the Wilcoxon signed-rank test for the overall sample, with false discovery rate (FDR) adjustment for multiple comparisons. TEI – total energy intake; SFA – saturated fatty acids; MUFAs – monounsaturated fatty acids; PUFAs – polyunsaturated fatty acids; ***p < 0.001.

Fig. 1.

Nutrient intake analysis by sex. The boxplots represent the distribution of the relative variation from the recommended DRI (%) for energy and macronutrients in male (blue) and female (red) orienteers. The central line within each box indicates the median; the box boundaries represent the interquartile range (IQR) (25th and 75th percentiles); and the whiskers extend to the most extreme data points within 1.5 × IQR. Individual points represent outliers. The vertical dashed line at 0 indicates no deviance from the recommended DRI. DRI: Dietary Reference Intakes; MUFAs: monounsaturated fatty acids; PUFAs: polyunsaturated fatty acids; SFA: saturated fatty acids.

Macronutrient intake

The mean carbohydrate contribution to TEI was 42.5 ± 6.5%, which was significantly below the DRI recommendations (p < 0.001). Only 30% of athletes met the recommended range for carbohydrate intake (95% CI: 14.6–51.9%), and the negative relative-variation value (− 17.5%, IQR 12.6) indicates a consistent deviation below recommended levels in both sexes. In contrast, total lipid intake was markedly higher than recommended, averaging 37.9 ± 6.00% of TEI (p < 0.001), exceeding the European Food Safety Authority (EFSA)²⁵ guideline of 20–3%. Only 30% of athletes met the recommended range (95% CI: 14.6–51.9%), and the relative-variation value (38.6%, IQR 28.7) confirmed that lipid intake substantially surpassed recommended levels. This reflects a dietary pattern dominated by lipids rather than quality carbohydrate sources such as legumes, whole grains, pasta, potatoes, and rice.

The analysis of fat quality further demonstrated substantial excesses across all lipid fractions: SFA averaged 29.9 ± 7.5% (p < 0.001), MUFA averaged 37.0 ± 5.1% (p < 0.001), and PUFA averaged 23.6 ± 7.9% (p < 0.001). These percentages refer to the distribution within total fat, not TEI. When expressed relative to TEI, SFA contribution exceeded the guideline of < 10% of TEI, given that overall fat intake was already above the recommended range^25,26. Relative-variation values were markedly positive for all lipid fractions (SFA: 204.0%, IQR 83.7; MUFA: 90.2%, IQR 31.6; PUFA: 354.2%, IQR 231.4), indicating substantial excess consumption.

Protein intake also significantly exceeded the DRI recommendations, accounting for 22.5 ± 15.0% of TEI (females: 24.5 ± 19.0%; males: 19.5 ± 5.2%) (p < 0.001). Only 20% of athletes met the DRI for protein intake (95% CI: 8.1–41.6%), and the positive relative-variation value (49.0%, IQR 32.6) demonstrates that protein intake was consistently above recommended levels. Mean dietary fibre intake was 31.5 ± 13.7 g/day, aligning closely with the recommended range for adults (25–38 g/day; p = 0.234).

In summary, carbohydrate intake was the only macronutrient consistently below recommended levels, whereas protein, total fat, and all lipid fractions were consumed in excess (Table 1).

Mineral intake

Figure 2. Mineral intake analysis by sex. The boxplots illustrate the distribution of the relative variation from the recommended Dietary Reference Intake (DRI) (%) for minerals in male (teal) and female (pink) orienteers. The central vertical line within each box represents the median; the box boundaries denote the interquartile range (IQR) (25th and 75th percentiles); and the whiskers extend to the most extreme data points within 1.5 × IQR. Individual points represent outliers. The vertical dashed line at 0 indicates no deviance from the recommended DRI.

Fig. 2.

shows the relative variation in mineral intake compared to the recommended DRIs in females and males.

Calcium intake averaged 805 ± 422 mg/day (females: 711 ± 344 mg; males: 945 ± 509 mg, p = 0.044), remaining below recommended levels for most athletes. Twenty‑5% met the DRI for calcium (95% CI: 11.2–46.9%), and the relative-variation value (− 27.9%, IQR 53.4) reflects a marked deviation below recommended intake. Zinc intake was also insufficient, at 11.3 ± 3.07 mg/day (p < 0.001), with only 15% of athletes meeting the DRI (95% CI: 5.2–36.0%) and a relative-variation value of − 25.1% (IQR 18.2). These deficiencies occurred despite the presence of mineral-rich foods in the athletes’ diets.

Iron intake averaged 15.3 ± 4.33 mg/day (p = 0.292), slightly above the general recommendation, with 55% of athletes achieving the DRI (95% CI: 34.2–74.2%) and a relative-variation value of 13.3% (IQR 62.2). Foods contributing to iron intake included lean meats, poultry, fish, legumes, and fortified cereals.

The mean potassium intake among OAs was 3546 ± 965 mg/day, exceeding both the national reference range for the adult population (2500–3000 mg/day, according to AESAN²⁴ and the adequate intake established by EFSA²⁵(3500 mg/day). However, no significant difference was observed compared with the DRI (p = 0.911). Only 55% of athletes met the recommended intake (95% CI: 34.2–74.1%), with a relative-variation value of 1.4% (IQR 39.7).

Magnesium intake averaged 422.7 ± 122.2 mg/day (p = 0.011), exceeding the DRI of 320–420 mg/day. 75% of athletes met the recommendation (95% CI: 53.1–88.8%), with a relative-variation value of 20.6% (IQR 38.5).

Phosphorus (1441 ± 516 mg/day) and sodium (4370 ± 1894 mg/day) intakes exceeded recommendations (both p < 0.001). High phosphorus intake was linked to foods such as meats, fish, dairy products, legumes, soy, and nuts, whereas excess sodium intake was associated with processed and salty foods, pastries, snacks, and cured meats. 90% of athletes met or exceeded the phosphorus DRI (95% CI: 70.0–97.2%) with a relative-variation value of 103.0% (IQR 69.7), while 95% met or exceeded the sodium DRI (95% CI: 76.4–99.7%) with a relative-variation value of 186.8% (IQR 176.1).

In the overall sample, significant differences were observed between DRI values and the mean intakes of phosphorus, sodium, and zinc (p < 0.001), magnesium (p = 0.011), and calcium (p = 0.044). Calcium (25%; 11.2–46.9%) and zinc (15%; 5.2–36.0%) showed the lowest adequacy levels, with relative-variation values of − 27.9% (IQR 53.4) and − 25.1% (IQR 18.2), respectively. In contrast, phosphorus, sodium, magnesium, and potassium showed substantially higher intakes relative to their DRIs, in some cases exceeding recommended values by wide margins (Table 2). These patterns indicate a nutritional profile characterised by inadequate calcium and zinc intake alongside excessive consumption of phosphorus and sodium, with magnesium and potassium generally within or above recommended ranges.

Table 2.

Mineral intake in elite orienteering athletes by sex and overall, compared with Dietary Reference Intakes (DRIs).

Minerals	DRI	Female	Male	All Mean ± SD Median [Q1–Q3]	% meeting DRI (IC 95%)	Relative variation from DRI (%) Median (IQR)	p-value (FDR adjusted)
Calcium (mg)	F: 1000 M: 1000	711.5 ± 344.3	945.1 ± 509.6	805.0 ± 422.0 721.5 [473.5–1007.7]	25 (11.2–46.9)	− 27.9 (53.4)	0.044*
Phosphorus (mg)	700	1517.5 ± 494.8	1326.5 ± 558.7	1441.1 ± 515.7 1421.2 [1249.1–1736.7]	90 (70.0–97.2)	103.0 (69.7)	< 0.001***
Iron (mg)	F: 18 M: 10	15.0 ± 4.9	15.7 ± 3.5	15.3 ± 4.33 14.0 [13.1–18.0]	55 (34.2–74.2)	13.3 (62.2)	0.292
Magnesium (mg)	F: 330 M: 350	422.6 ± 146.1	422.8 ± 83.6	422.7 ± 122.2 398.0 [342.7–465.8]	75 (53.1–88.8)	20.6 (38.5)	0.011**
Potassium (mg)	3500	3409.8 ± 1068.7	3751.3 ± 808.6	3546.4 ± 965.2 3547.9 [2840.0–4229.3]	55 (34.2–74.1)	1.4 (39.7)	0.911
Sodium (mg)	≤ 1500	4263.6 ± 2015.9	4530.4 ± 1595.2	4370.3 ± 1818.8 4301.9 [2975.2–5616.9]	5 (0.3–23.6)	186.8 (176.1)	< 0.001***
Zinc (mg)	15	11.1 ± 3.3	11.7 ± 2.8	11.3 ± 3.07 11.2 [9.5–12.2]	15 (5.2–36.0)	− 25.1 (18.2)	< 0.001***

Data are presented as mean ± standard deviation (SD) and median [Q1–Q3]. The percentage of athletes meeting Dietary Reference Intakes (DRIs) is shown with 95% confidence intervals (Wilson method). Relative variation from DRIs was calculated as (intake − DRI)/DRI × 100 and is presented as median (interquartile range, IQR). P-values refer to differences from DRIs tested using the Wilcoxon signed-rank test for the overall sample, with false discovery rate (FDR) adjustment for multiple comparisons. Female (F) and Male (M) DRIs are indicated where sex-specific values exist; *p < 0.05; ** p < 0.01; ***p < 0.001.

Sex-specific comparisons revealed no significant differences between males and females in the absolute intake of any nutrient (all p > 0.05). However, when analysing the relative variation from the DRI, a significant sex difference emerged for iron: males showed a smaller deviation from their sex-specific DRI than females, as illustrated in Fig. 2. No sex differences were observed in the relative variation for calcium or any other mineral or vitamin.

Vitamin intake

Vitamin intake relative to DRIs (Fig. 3) revealed the highest mean intakes for vitamin C and vitamin B12, particularly in males, exceeding 250% of the DRI.

Fig. 3.

Vitamin intake analysis by sex. The boxplots illustrate the distribution of the relative variation from the recommended Dietary Reference Intake (DRI) (%) for vitamins in male (teal) and female (pink) orienteers. The central vertical line within each box represents the median; the box boundaries denote the interquartile range (IQR) (25th and 75th percentiles); and the whiskers extend to the most extreme data points within 1.5 × IQR. Individual points represent outliers. The vertical dashed line at 0 indicates no deviance from the recommended DRI.

Intakes of vitamins B1 (thiamine), B2 (riboflavin), B3 (niacin), B6, E, and A were generally between ~ 100–150% of recommendations (with vitamin B1 slightly higher) across the sample. Vitamin D intake (3.74 ± 2.41 µg/day; p = 0.043) was substantially below both historical FAO/WHO targets (5 µg/day) and current DRI recommendations (15 µg/day)^10,27. Only 30% of athletes met the recommended vitamin D intake (95% CI: 14.6–51.9%), and the relative-variation value (− 31.5%, IQR 72.2) indicates a clear deviation below recommended levels. This pattern reflects low consumption of foods such as fatty fish, whole milk, liver, and butter.

Folic acid intake (428 ± 160 µg/day; p = 0.837) approximated the 400 µg/day guideline¹². 55% of athletes met the DRI (95% CI: 34.2–74.2%), with a relative-variation value of 2.1% (IQR 69.6), though lower values were observed in females, reflecting limited intake of folate-rich vegetables. Vitamin A intake (1012 ± 723 µg/day; p = 0.911) was close to the recommended 700–900 µg/day¹⁴, with 55% of athletes meeting the DRI (95% CI: 34.2–74.2%) and a relative-variation value of 14.6% (IQR 80.4).

B-complex vitamins showed consistent adequacy. Vitamin B1 averaged 1.68 ± 0.416 mg/day, with 95% of athletes meeting the DRI (95% CI: 76.4–99.7%) and a relative-variation value of 63.8% (IQR 53.4). Vitamin B2 averaged 1.85 ± 0.543 mg/day, with 75% meeting the DRI (95% CI: 53.1–88.8%) and a relative-variation value of 24.5% (IQR 47.7). Vitamin B3 intake was 24.2 ± 6.55 mg/day, with 85% meeting the DRI (95% CI: 64.0–94.8%) and a relative-variation value of 54.0% (IQR 59.1). Vitamin B6 intake averaged 2.5 ± 0.619 mg/day, with 95% meeting the DRI (95% CI: 76.4–99.7%) and a relative-variation value of 36.2% (IQR 42.7). Vitamin B12 intake was 4.73 ± 2.76 µg/day, with 85% meeting the DRI (95% CI: 64.0–94.8%) and a relative-variation value of 120.8% (IQR 181.5).

Vitamin C intake (169 ± 90.8 mg/day; p < 0.001) was well above recommendations, with 85% of athletes meeting the DRI (95% CI: 64.0–94.8%) and a relative-variation value of 159.7% (IQR 232.8). Vitamin E intake averaged 15.4 ± 5.90 mg/day (p = 0.014), with 75% meeting the DRI (95% CI: 53.1–88.8%) and a relative-variation value of 23.2% (IQR 52.2).

Overall, intakes of vitamins A, C, E, and the B-complex group exceeded recommended levels for most athletes, whereas vitamin D showed the lowest adequacy, as illustrated in Table 3; Fig. 3, showing both numeric values and distribution of vitamin intakes relative to DRIs.

Table 3.

Vitamin intake in elite orienteering athletes by sex and overall, compared with Dietary Reference Intakes (DRIs).

Vitamins	DRI	Female	Male	All Mean ± SD Median [Q1–Q3]	% meeting DRI (IC 95%)	Relative variation from DRI (%) Median (IQR)	p-value (FDR adjusted)
Folic acid (µg)	400	408.7 ± 176.3	432.5 ± 134.0	418.2 ± 157.4 408.3 [259.8–538.2]	55 (34.2–74.2)	2.1 (69.6)	0.891
Vitamin A (µg)	F: 800 M: 1000	961.0 ± 589.9	1084.0 ± 843.5	1010.2 ± 683.7 917.0 [530.3–1159.5]	55 (34.2–74.2)	14.6 (80.4)	0.911
Vitamin B1 (mg)	F: 0.9 M: 1.2	1.5 ± 0.4	1.9 ± 0.3	1.67 ± 0.41 1.68 [1.45–1.99]	95 (76.4–99.7)	63.8 (53.4)	< 0.001***
Vitamin B12 (µg)	2	4.2 ± 2.8	5.5 ± 2.4	4.73 ± 2.64 4.42 [2.65–6.28]	85 (64.0–94.8)	120.8 (181.5)	< 0.001***
Vitamin B2 (mg)	F: 1.4 M: 1.6	1.7 ± 0.5	2.0 ± 0.5	1.83 ± 0.53 1.78 [1.53–2.05]	75 (53.1–88.8)	24.5 (47.7)	0.011**
Vitamin B3 (mg)	F: 15 M: 20	22.9 ± 6.0	27.0 ± 6.4	24.6 ± 6.33 25.1 [22.9–28.5]	85 (64.0–94.8)	54.0 (59.1)	< 0.001***
Vitamin B6 (mg)	F: 1.6 M: 1.8	2.4 ± 0.6	2.7 ± 0.6	2.51 ± 0.60 2.42 [2.06–2.92]	95 (76.4–99.7)	36.2 (42.7)	< 0.001***
Vitamin C (mg)	60	171.4 ± 93.2	145.3 ± 91.3	160.9 ± 90.9 155.8 [78.3–217.9]	85 (64.0–94.8)	159.7 (232.8)	< 0.001***
Vitamin D (µg)	5	3.2 ± 2.1	4.6 ± 2.5	3.75 ± 2.31 3.42 [1.57–5.18]	30 (14.6–51.9)	− 31.5 (72.2)	0.043*
Vitamin E (mg)	F: 11 M: 12	14.5 ± 6.9	15.9 ± 3.6	15.0 ± 5.73 13.6 [11.5–17.5]	75 (53.1–88.8)	23.2 (52.2)	0.014**

Data are presented as mean ± standard deviation (SD) and median [Q1–Q3]. The percentage of athletes meeting Dietary Reference Intakes (DRIs) is shown with 95% confidence intervals (Wilson method). Relative variation from DRIs was calculated as (intake − DRI)/DRI × 100 and is presented as median (interquartile range, IQR). P-values refer to differences from DRIs tested using the Wilcoxon signed-rank test for the overall sample, with false discovery rate (FDR) adjustment for multiple comparisons. Female (F) and Male (M) DRIs are indicated where sex-specific values exist; *p < 0.05; ** p < 0.01; ***p < 0.001.

Taken together, the dietary assessment revealed a heterogeneous pattern of nutrient adequacy, characterised by insufficient intakes of key nutrients such as carbohydrates, calcium, zinc, and vitamin D, together with excessive intakes of protein, total lipids, and several fatty‑acid fractions. These findings provide the basis for the subsequent discussion of their potential implications for the nutritional profile of EOAs.

Discussion

The study evaluated the dietary intake of EOAs, a discipline classified as an endurance sport due to its prolonged aerobic demands²⁸ and characterised by the combination of high-intensity interval exercise with navigation²⁹. OAs demonstrate substantially increased energy expenditure and pronounced fluid and electrolyte losses during exercise¹⁸, and research confirms that a proper diet has a positive impact on an athlete’s performance, body composition, and recovery after exercise³⁰. Very few studies have been conducted on dietary assessment in orienteering, especially among EOAs. Moreover, data collected with detailed dietary records in real-world competitive settings are limited, and it remains unclear whether EOAs meet age-specific DRIs while falling short of athlete-focused carbohydrate and protein guidelines. Therefore, the assessment was conducted as a single cross-sectional study during the “35° Trofeo Internacional Murcia Costa Cálida” in Spain, organised by FEDO and F.O.R.M. Dietary intake was subsequently assessed using a four-day food record based on the food-weighing method, capturing both solid and liquid intake.

Analysis of the EOAs’ diet assessment showed that energy intake averaged 2144 ± 679 kcal/day. Both sexes generally fell below recommended ranges, with lower adequacy among males. This aligns with previous reports of low energy availability (LEA) among endurance athletes, particularly females, which can lead to Relative Energy Deficiency in Sport (RED-S) and compromise bone health, menstrual function, and immunity^31–33. A recent case study further illustrated these risks, reporting a 23-year-old EOA who developed anorexia nervosa. The study highlighted how prolonged engagement in endurance-based competition, combined with dietary restrictions, can result in serious health consequences, emphasising the need for careful monitoring of energy intake and health in high-level endurance sports³⁴. It should be added that research by Moss et al.⁶ showed that 76.8% of endurance athletes do not consume enough energy, and 95.8% do not consume enough carbohydrates. Therefore, it is not surprising that the EOA group had a significantly lower carbohydrate intake (42.5 ± 6.5% of TEI) compared to the recommended 55–65% of TEI or 6–10 g/kg/day for endurance athletes^3,13,35. The results are consistent with studies of other diseases affecting endurance athletes^36,37, runners^38,39, and ultrarunners^40,41 as well as elite and sub-elite endurance, team, and strength athletes⁴². Such low carbohydrate intake may compromise glycogen availability, which is critical for endurance performance, and could partly explain the reliance on lipids as an energy source^3,35. Insufficient carbohydrate availability may reduce glycogen stores, impair high-intensity efforts, and increase reliance on fat oxidation, as evidenced by the elevated lipid intake (37.9 ± 6.0%). In orienteering, where sustained running is coupled with continuous decision-making and navigation under fatigue, inadequate carbohydrate availability may also impair cognitive performance and increase the likelihood of navigational errors, amplifying performance costs beyond the physiological domain.

Fat quality analysis revealed substantial SFA (p < 0.001), MUFA (p < 0.001), and PUFA (p < 0.001) excesses. These values indicate that total fat intake was well above the recommended range of 20–35% of TEI, with SFA exceeding the less than 10% energy guideline^3,35. When on a low-fat diet, the levels of essential fatty acids and some minerals (especially zinc) may be too low, and the low-fat diet itself may negatively affect health and performance⁴³. The results obtained are consistent with observations by researchers who found that athletes⁴⁴ and elite Ethiopian runners⁴⁵ reached or exceeded the recommended body fat levels. Meanwhile, too little fat intake (13.4%) was observed in elite Kenyan runners⁴⁶.

Protein intake in EOAs exceeded recommendations (22.5 ± 15.0% vs. 15–20% of energy), also surpassing the general guidance for endurance athletes (15–20% of TEI or 1.2–2.0 g/kg/day)³. These findings align with previous studies showing that most athletes meet or exceed recommended protein intake^38,42,44. Notably, the only study describing the dietary profile of elite orienteering competitors⁴⁷ showed that pre-competition breakfasts were characterised by low macronutrient intake (carbohydrate, protein, and lipid), which supported the notion that suboptimal fuelling may occur in this discipline. In contrast, fibre intake in EOAs averaged 31.5 ± 13.7 g/day, p = 0.234, which was close to adult recommendations (25–38 g/day, p = 0.189), suggesting adequate consumption of plant-based foods despite a carbohydrate pattern that may not align with sport-specific needs⁶. Consistent with prior evidence, meeting fibre recommendations was more common among women than men (p < 0.05)⁶.

The average calcium intake (805 ± 422 mg/day, p = 0.044) was significantly below the recommended 1,000 mg/day for adults and endurance athletes^6,10, potentially increasing the risk of impaired bone health with long-term inadequate intake. Zinc intake was also insufficient (11.3 ± 3.07 mg/day), compared to the recommended 8–11 mg/day, considering increased needs in athletes due to sweat losses and metabolic demands^6,13. The inadequate intake of calcium and zinc is consistent with other endurance athlete studies reporting inadequate intake of bone-related nutrients^6,11. These deficiencies increase the risk of stress fractures and impaired recovery, particularly in female athletes, who are more vulnerable to low calcium and iron status^7,11. Other studies also confirmed lower-than-recommended levels of calcium^6,38,48,49 and zinc^6,49 intakes among athletes.

Conversely, phosphorus (1441 ± 516 mg/day) and sodium (4370 ± 1819 mg/day) intakes exceeded recommendations (> 100% above the DRI), likely reflecting a greater contribution from processed foods and cured meats. Excess sodium intake (> 4 g/day) exceeds the WHO limit of 2 g/day sodium or 5 g salt/day, which may raise concerns about cardiovascular strain, particularly during periods of high training load⁵⁰. Similar observations were reported by Moss et al.⁶, who found that most endurance athletes consumed sodium above recommended levels. In contrast, iron intake in the present sample (15.3 ± 4.33 mg/day) was slightly above general adult recommendations (8–18 mg/day)⁶. However, monitoring remains essential, especially among female athletes, given menstrual losses¹¹ and the higher incidence of iron deficiency reported in athletic populations⁴⁸. Notably, previous studies have documented iron intakes below recommended levels in endurance athletes, reinforcing the need for ongoing surveillance and individualised guidance^6,49,51. Although mean iron intake was slightly above general recommendations, the distribution indicated lower intakes among females, suggesting targeted monitoring is warranted.

The EOA’s potassium intake (3546 ± 965 mg/day) met and even exceeded general recommendations, which may help maintain electrolyte balance and support muscle function during prolonged exercise. However, statistical analysis in comparison with the DRI revealed no significant differences (p = 0.911), indicating considerable interindividual variability. The average magnesium intake (422.7 ± 122.2 mg/day) exceeded the DRI (p = 0.011), which is consistent with its role in energy metabolism and muscle function during endurance exercise. These findings contrast with those of Moss et al.⁶, who reported that more than half of endurance athletes failed to meet magnesium recommendations, but partially align with the results of Clarkson and Haymes⁴⁸, who observed adequate magnesium intake among athletes.

Vitamin D showed the lowest intake among EOAs (3.75 ± 2.31 µg/day). Importantly, we assessed dietary intake but did not measure 25(OH)D; therefore, low intake should not be interpreted as vitamin D insufficiency per se. Nevertheless, athletes did not meet even the minimum recommended intake. These results align with findings in elite Spanish athletes, among whom 82% displayed insufficient serum 25(OH)D levels despite regular outdoor training and favourable climate conditions⁵². A systematic review and meta-analysis estimated that approximately 30% of elite athletes worldwide have vitamin D insufficiency (< 50 nmol/L), with prevalence reaching up to 74% in winter months^53,54. Furthermore, differences between indoor and outdoor athletes are minimal, indicating that sun exposure alone does not guarantee adequate vitamin D status⁵⁵. These results highlight that dietary intake and lifestyle factors play a critical role, and that monitoring and diet-first strategies (with supplementation only when clinically indicated) should be considered as part of broader nutritional approaches supporting bone health, muscle function, and immunity^10,56.

Interestingly, similar patterns of inadequate vitamin D intake have been observed in clinical populations living in sunny regions. De la Rubia Ortí et al.⁵⁷ reported low dietary vitamin D intake among patients with multiple sclerosis in the Valencian region, although their study did not directly assess vitamin D status (25(OH)D), which was associated with elevated interleukin-6 (IL-6) levels, suggesting a potential association rather than a demonstrated causal link. This reinforces the notion that sun exposure alone does not guarantee adequate vitamin D status, highlighting the need for dietary strategies and carefully supervised supplementation when clinically indicated in both athletic and clinical settings.

Folic acid intake among EOAs averaged 418 ± 157.4 µg/day (p = 0.891) and was close to the general recommendation of 400 µg/day¹², but may be insufficient in light of increased metabolic demands associated with endurance sports and orienteering. Evidence suggests that more than half of endurance athletes fail to meet folate requirements, which can compromise oxygen transport, muscle recovery, and energy metabolism⁶. Furthermore, OAs require high-quality diets rich in micronutrients to sustain cognitive performance and prolonged physical effort⁵⁸. Therefore, ensuring adequate folate intake through diet or carefully monitored supplementation should be considered a priority in nutrition strategies for athletes engaged in endurance and orienteering disciplines.

The average intake of vitamin A and vitamin C was above the recommended levels, while vitamin E intake averaged 15.4 ± 5.90 mg/day and exceeded the sex‑specific recommendation of 11–12 mg/day. These findings are consistent with those of Passos et al.⁵⁹, who reported that vitamin A and vitamin C intake exceeded the daily reference values, whereas vitamin E intake was below the recommended levels in amateur marathoners. A study of ultra-endurance athletes showed that their intake of vitamins E and C was insufficient⁶⁰.

Conversely, B-complex vitamins (B1, B2, B3, B6, B12) were significantly above DRIs, likely due to high consumption of animal protein and plant-based foods. Interestingly, a study by Moss et al.⁶ showed that the recommended daily intake of vitamin B12 (46.8% vs. 22.9%) was not met by more women than men (p < 0.05).

Significant discrepancies were observed between DRI values and the macronutrient intakes of EOAs, with a sex‑specific difference limited to iron when assessed as relative variation from the DRI; no sex differences were found in absolute intakes. Overall, athletes showed suboptimal carbohydrate intake, excessive protein and fat, inadequate vitamin D, low calcium and zinc, and high sodium and phosphorus. These imbalances may impair glycogen-dependent performance, recovery, skeletal health, and cardiometabolic function. Systematic nutrition strategies - optimising carbohydrate periodisation, limiting saturated fat (< 10% TEI), correcting micronutrient deficiencies, and moderating sodium—are recommended. Future studies should combine controlled dietary interventions with biochemical and performance outcomes to assess effectiveness.

Practical implications

To optimise health and performance in Orienteering:

• Increase carbohydrate intake to meet endurance demands and restore glycogen stores.

• Reduce saturated fat while maintaining MUFAs and PUFAs for cardiovascular and anti-inflammatory benefits.

• Ensure adequate intake of calcium, vitamin D, and folate from dairy, fortified foods, leafy greens, and fatty fish.

• Monitor sodium intake and limit processed foods to comply with WHO guidelines.

• Maintain high-quality protein intake but avoid excessive amounts that displace carbohydrates.

• Emphasise food-based strategies to improve vitamin D, calcium, and zinc intake, rather than assuming supplementation as the primary approach.

Strengths and limitations

This study provides novel insights into EOAs, an underrepresented group in sports nutrition research, showing that DRI recommendations are not consistently met even at elite performance levels. Limitations include self-reported dietary records, a lack of biochemical markers, the need to interpret adequacy indicators cautiously due to potential day-to-day intake variability, small effect sizes, and a modest sample size (n = 20), which may limit statistical power and generalisability. The use of a single competition‑based data collection period may also limit the capture of habitual nutrient intake. Larger studies incorporating objective biomarkers and diverse athletic populations are needed to confirm these findings.

Conclusion

EOAs demonstrated significant nutritional imbalances, including low energy and carbohydrate intake, excessive saturated fat, and inadequate calcium, zinc, and vitamin D, with no significant sex differences in absolute nutrient intakes. These patterns may influence performance, recovery, and long‑term health, although such implications should be interpreted with caution in the absence of biochemical markers. Findings highlight the need for individualised nutritional strategies emphasizing energy and carbohydrate adequacy, micronutrient optimisation, while prioritising diet‑first approaches to vitamin D (with supplementation only when clinically indicated). Future research should investigate the impact of targeted dietary interventions (supported by biomarker‑based assessments of nutrient status) on athletic performance and health outcomes in this population.

Supplementary Information

Below is the link to the electronic supplementary material.

Author contributions

W.M-K., V.S.S., E.D.R., and M.Z.G. contributed to the conceptualization of the manuscript, performed data analysis, and prepared the original draft. W.M-K. and E.D.R were involved in the data collection. P.C., A.D, H.E-I., I.S., and D.A.S.S were responsible for methodology, manuscript review, and editing. All authors have read and agreed to the published version of the manuscript.

Funding

The authors self-funded this study; thus, no financial support was received.

Data availability

The data analyzed during this study are available from the corresponding author on reasonable request.

Declarations

Competing interests

The authors declare no competing interests.

Ethics declarations

All experimental procedures were reviewed and approved by the Ethics Committees of the Wroclaw University of Health and Sport Sciences (approval no. 19/2021) and of the Faculty of Human Kinetics, University of Lisbon (approval no. 13/2022).