Diet Quality, Carotenoid Status, and Body Composition in NCAA Division I Athletes

Abstract

Objectives:

In this paper, we examined diet quality and associations between changes in skin carotenoids and body composition among selected NCAA Division I athletes.

Methods:

Athletes from women’s (rowing, swimming, gymnastics) and men’s (swimming, wrestling) teams at a large Midwest university (N = 129) completed one online food frequency questionnaire and 2 in-person visits, once in-season and once out-of-season, to assess skin carotenoids and body composition. Diet quality was assessed via Healthy Eating Index-2015 (HEI). Carotenoids were measured via resonance Raman spectroscopy and body composition via dual-energy x-ray absorptiometry. ANOVA and Pearson correlations were used to test differences between teams and determine association between changes from in-season to out-of-season.

Results:

Mean HEI score for all athletes was 71.0. Women’s rowing reported the highest diet quality (73.5), men’s wrestling lowest (56.5). Skin carotenoids decreased for all teams, except men’s wrestling, from in-season to out-of-season. Body fat percentage increased for women and decreased for men. There was a moderate inverse association between changes in skin carotenoids and body fat percentage (r = −.334, p = .001).

Conclusions:

Suboptimal diet quality coupled with decreases in skin carotenoids and increases in body fat percentage from in-season to out-of-season may justify dietitian-led interventions year-round to improve dietary patterns in collegiate athletes.

Nutrition in sport is a high priority, as athletes often manipulate dietary intakes for fuel optimization to maximize functional and metabolic adaptations in an effort to enhance performance.^1,2 To provide evidence-based dietary guidance for athletes, recommendations for exercise and sport nutrition have been created to support adequate intakes and periodization of fluid, energy, macro-, and micronutrients to meet the demands of sport.^1–4 Adherence to these recommendations may result in performance gains, such as improved endurance exercise capacity.^1–4 Conversely, inadequate dietary intakes may impede athletes’ abilities to meet the unique requirements for training, performance, and recovery throughout competition cycles.^1,2

In addition to modifying dietary intakes to fuel performance, athletes also may manipulate their dietary patterns to manage body weight or body composition.⁵ This is often evident in weight-sensitive sports, as low body fat percentages (BF%) are considered desirable to maximize strength-to-mass ratio or to achieve an aesthetic physique for competition.⁶ Whereas no conclusive evidence provides optimal ranges for sport-specific BF%, body weight and body composition appear to be related to performance in 3 major categories: (1) gravitational and endurance-type sports, such as rowing and swimming, as gravitational forces work against body mass; (2) weight-class sports, such as wrestling, where failing to “make weight” may eliminate the athlete from competition; and (3) aesthetically-judged sports, such as gymnastics, where body aesthetic is considered a factor in successful performance.⁶ Among these sports, 94% of athletes report using restrictive dieting and other extreme tactics, such as prolonged fasting and active dehydration, to manage weight for competition, predisposing them to suboptimal, and possibly deleterious, dietary patterns.^6–10

Barriers also exist that can prevent college students from engaging in optimal dietary behaviors. These may include a lack of access to nutritious foods, abundance of energy-dense and highly processed food choices in dining facilities, financial limitations, and social pressure.¹¹ Student athletes face additional barriers, such as competing time constraints between academics and sport, appetite fluctuations throughout training cycles, and lack of evidence-based knowledge specific to nutritional requirements for athletes.¹² These barriers, coupled with the pressure to achieve a desirable body weight and body composition, may place collegiate athletes at risk for suboptimal dietary patterns.

Indeed, despite evidence supporting adherence, athletes at all levels of competition consistently fail to meet established sport nutrition recommendations.^13–16 Gaps in adherence to these recommendations may also be indicative of lower overall diet quality. As lifestyle behaviors established during the collegiate years can significantly influence health outcomes throughout adulthood, it is critical to develop positive dietary patterns during this formative period.¹⁷ This is particularly important for collegiate athletes, who may greatly exceed minimum physical activity recommendations during their active participation in competitive sports but often do not maintain this heightened level of activity in the long term.^18,19

Whereas sport nutrition recommendations are based upon meeting specific targets for fluid, energy, macro-, and micronutrient intakes, individuals often choose foods and beverages based upon availability and palatability. Therefore, tailored dietary guidance for athletes should encourage choosing foods that fit into their active lifestyle and help them to meet specific sport nutrition requirements, while taking into account food preferences and how these choices align with the United States (US) Dietary Guidelines for Americans (DGA) for a health-promoting dietary pattern that will persist beyond years in sport.^1,20,21 Nutrition education and recommendations targeting nutrient needs across an athlete’s competition cycle are also necessary to promote optimal nutritional status during times of transition. Yet, there is little research investigating the diet quality of athletes based upon adherence to guidelines for overall dietary patterns.

As consumption of a nutrient-dense, plant-based dietary pattern is associated with displacement of energy-dense foods, diets high in vegetables and fruits are important to helping athletes achieve performance-related goals and manage body composition.^1,22 Therefore, accurate assessment of vegetable and fruit intakes is paramount to informing individualized recommendations. To improve the accuracy of self-report dietary assessments, biomarkers have been utilized to complement and confirm self-reported intakes.²³ One biomarker of dietary exposure to vegetables and fruits includes objective skin carotenoid measures to define changes in dietary intakes.^23–25 Currently, there are no published studies utilizing this rapid and non-invasive measurement in student athletes nor are there studies investigating the relationship between skin carotenoid changes and changes in BF% between performance seasons.

Assessment of dietary intakes is vital to providing appropriate and individualized dietary guidance to athletes, yet there is a paucity of research investigating the overall dietary patterns of individuals participating in National Collegiate Athletic Association (NCAA) Division I (DI) athletics. As such, little is known about the overall diet quality of collegiate athletes.^13–16 Thus, the purpose of this study was to define dietary patterns in NCAA DI athletes to identify differences in diet quality across a variety of athletic teams at increased risk for deleterious dietary patterns due to the high demands of sport. A secondary aim was to examine the relationship between changes in skin carotenoids and BF% at 2 time points: once in-season and once out-of-season. We hypothesized that athletes were not meeting dietary recommendations in line with the DGA. We also hypothesized that changes in vegetable and fruit intakes, as assessed by skin carotenoids, would demonstrate an inverse association with changes in BF%.

METHODS

Participants

NCAA DI collegiate athletes from a variety of teams participating in endurance-based, weight-class, and aesthetically-judged sports were recruited in-person by study personnel during routine body composition assessment visits and enrolled in this study. Teams included women’s rowing (Wrow), women’s swimming (Wswim), women’s gymnastics (Wgym), men’s swimming (Mswim), and men’s wrestling (Mwr) from a large Midwest university in the US. Participants were English-speaking (≥ 18 years of age) and voluntarily agreed to participate. Athletes were excluded if they were enrolled in another clinical trial, diagnosed with active metabolic or chronic digestive illness (eg, Crohn’s disease), or pregnant.

Upon enrollment, athletes were provided a unique weblink to complete one online dietary assessment. Participants also completed 2 in-person clinic visits with a registered dietitian (RD) trained in sports nutrition. These visits lasted approximately 30 minutes and were completed on The Ohio State University campus at the Jameson Crane Sports Medicine Institute. At each clinic visit, skin carotenoids and body composition were measured objectively, and instructions for completing the online dietary assessment were provided. Athletes received no nutrition education at these visits. Clinic visits occurred in spring and autumn semesters. Visits were then categorized for analysis as occurring in-season or out-of-season for each team. In-season was defined as during competition season, including one month before or after official competition dates, while out-of-season was defined as at least 2 months outside of competition season. Athletes received no compensation for their participation.

Dietary Pattern Assessments

Dietary intake data were obtained using the VioScreen Web-based, self-administered 30-day graphical food frequency questionnaire (Viocare, Inc., Princeton, NJ) that queried participants about their previous 30 days of food and beverage intakes. This tool is based on the validated Fred Hutchinson Cancer Research Center dietary assessment and collects data on 156 food items or food groups.²⁶ This dietary assessment has been used widely in research, including in epidemiological studies such as the Women’s Health Initiative (WHI) as well as multiple lifestyle interventions.^27,28 VioScreen utilizes food and nutrient information from the University of Minnesota Nutrition Coordinating Center Food and Nutrient Database for all analyses (Nutrition Data System for Research, v45).

Total Healthy Eating Index-2015 (HEI) scores were calculated to determine compliance with the 2015–2020 DGA recommendations as a measure of diet quality.^20,29 The HEI provides numeric values reflecting the adequacy of intakes for each component of a dietary pattern to generate a total diet score ranging from zero to 100.^29,30 The total score is a composite sum of 13 components, which include total fruits, whole fruits, total vegetables, greens and beans, whole grains, dairy, total protein foods, seafood and plant proteins, fatty acids, refined grains, sodium, added sugars, and saturated fats.^29,30 For all components, a higher score is indicative a better quality in line with the DGA recommendations, with a total score of 100 representing maximum compliance with the guidelines.

Carotenoid Assessments

At both clinic visits, skin carotenoids were measured in triplicate on the palm of the hand with a Pharmanex NuSkin Biophotonic Scanner S3 (NuSkin Enterprises, Provo, UT), and the mean calculated for subsequent analyses. This scanner emits a LED light on the surface of the skin for approximately 2 minutes and employs resonance Raman spectroscopy to estimate carotenoid levels, reported in Raman intensity counts (RRS counts). This method has been shown to be reliable and reproducible and has been correlated with plasma carotenoid concentrations (r = .73, p < .001) as an exposure biomarker for change in vegetable and fruit intakes.²⁸

Body Composition Assessments

We used whole-body dual-energy x-ray absorptiometry (DXA; Lunar iDXA, GE Healthcare, Chicago, IL) to measure 3-compartment body composition, including lean mass, fat mass, and bone mineral content, to assess total BF%.³¹ The instrument was calibrated according to manufacturer guidelines prior to use, and all software was up-to-date. The same certified general x-ray machine operator completed all scans to eliminate potential inter-technician variability. Participants were instructed to come well-hydrated and to abstain from exercise the day of their scheduled scan, but they were not required to fast. Participants were asked to wear light athletic apparel, removing heavy clothing, shoes, and jewelry. They were instructed on proper alignment, lying flat on the center of the bed with arms at sides 2 inches from body and legs straight and shoulder-width apart with feet flexed. A positioning strap was utilized to ensure all body parts remained within the scanning window. If needed, broad participants had a second positioning strap placed around the chest and arms to ensure placement within scanning window. Utilization of DXA has been documented to be accurate and reliable, with estimates demonstrating a precision error < 0.9% for total BF%.^31,32

Data Analysis

Results were reported as mean ± standard deviation values for the entire cohort as well as by team for total HEI score, HEI component scores, skin carotenoids, and BF%. Only those with completed dietary assessments were included in analysis of HEI scores, and only those completing both in-season and out-of-season clinic visits were included in analyses of skin carotenoid and BF% data. One-way analysis of variance (ANOVA) with Tukey post hoc comparisons was used to identify differences across teams for mean total HEI score, skin carotenoids, and BF%. To examine associations among change in skin carotenoids and change in BF% between in-season and out-of-season, Pearson correlation analyses were used. Data analyses were conducted using IBM SPSS statistical software, version 25. Significance was set to a critical level of p ≤ .05.

RESULTS

All athletes who were approached for inclusion consented to participation, and a total of 143 NCAA DI athletes were enrolled. Fourteen participants completed no dietary assessment and only one clinic visit; therefore, they were excluded from final analyses. Of the final cohort, comprised of individuals with one complete dietary assessment and/or those with both in-season and out-of-season clinic visits (N = 129), 21.7% (N = 28) athletes only completed the dietary assessment, 17.8% (N = 23) only completed in-season and out-of-season skin carotenoid and DXA scans, and 60.5% (N = 78) completed the dietary assessment as well as both in-season and out-of-season skin carotenoid and DXA scans (Table 1). Overall, 87% of dietary assessments (N = 92) were completed by athletes immediately upon enrollment in the spring semester, which was in-season for the Wrow team and out-of-season for the Wswim, Wgym, Mswim, and Mwr teams. Most participants were women (69.8%). Approximately 47% of athletes (N = 60) were on the Wrow team, and 16.3% (N = 21) were on the Wswim team, 7.0% (N = 9) on the Wgym team, 17.8% (N = 23) on the Mswim team, and 12.4% (N = 16) on the Mwr team.

Table 1.

Demographic Information and Descriptive Statistics for a Cohort of NCAA Division I Athletes

Characteristic	Category	Frequency % (N)
Sex	Female	69.8 (90)
	Male	30.2 (39)
Team	Women’s rowing	46.5 (60)
	Women’s swimming	16.3 (21)
	Women’s gymnastics	7.0 (9)
	Men’s swimming	17.8 (23)
	Men’s wrestling	12.4 (16)
Assessments completed	Dietary assessment only	21.7 (28)
	In-season and out-of-season dual-energy x-ray absorptiometry and skin carotenoid scans only	17.8 (23)
	Both dietary assessment and in-season and out-of-season dual-energy x-ray absorptiometry and skin carotenoid scans	60.5 (78)

Mean total HEI score for all athletes was 71.0 ± 11.2. Wrow had the highest HEI score (73.5 ± 9.7), and Mwr had the lowest score (56.5 ± 5.7, Table 2). There was a statistically significant difference in total diet quality among teams (p = .002). Total diet quality between individual teams was significantly lower for Mwr compared to Wrow (p = .001) and Wswim (p = .007). We noted no other statistically significant difference among teams. Overall, athletes demonstrated highest diet quality in HEI component scores for total protein foods (mean score 4.6 ± .9 out of 5), whole fruits (4.5 ± 1.0 out of 5), and total fruits (4.3 ± 1.2 out of 5). In contrast, they demonstrated lowest diet quality in the fatty acids (mean score 5.1 ± 2.8 out of 10) and whole grains (6.3 ± 3.0 out of 10) components. Figure 1 shows the overall patterns of diet quality based upon HEI component scores for each team.

Table 2.

Mean Healthy Eating Index-2015 Scores in a Cohort of NCAA Division I Athletes

	Team
Variable	Women’s Rowing (N = 56) Mean ± SD	Women’s Swimming (N = 17) Mean ± SD	Women’s Gymnastics (N = 7) Mean ± SD	Men’s Swimming (N = 19) Mean ± SD	Men’s Wrestling (N = 7) Mean ± SD	p
HEI-2015	73.5 ± 9.7a	72.8 ± 10.8a	68.9 ± 12.9a,b	68.2 ± 12.7a,b	56.5 ± 5.7b	.002

Mean Healthy Eating Index-2015 (HEI) scores are depicted to demonstrate overall diet quality reported by each team on 30-day food frequency questionnaires. Scores were assessed by one-way ANOVA followed by Tukey post hoc tests. Superscripts denote significant differences between groups (p ≤ .05).

Figure 1.

Radar Plot of Healthy Eating Index-2015 Component Scores in a Cohort of NCAA Division I Athletes

Component Healthy Eating Index-2015 (HEI) scores for each team are displayed simultaneously to visualize overall dietary patterns. The solid line at the outermost edge of the plot represents an HEI score of 100, or a dietary pattern that is maximally compliant with the US Dietary Guidelines for Americans, where the center of the circle represents a score of 0 for all components of the HEI. Scores are plotted as percentage of goal for each component.

Mean skin carotenoid score for all athletes was 34,607 Raman intensity counts in-season and 33,458 out-of-season. Women’s rowing demonstrated the highest score while in-season and Wswim while out-of-season (Table 3). All teams had lower skin carotenoids when out-of-season compared to in-season except Mwr. Women’s rowing had a significantly greater change in skin carotenoids from in-season to out-of-season compared to Mwr (p = .02).

Table 3.

Mean in-season and out-of-season Skin Carotenoids and Body Fat Percentages in a Cohort of NCAA Division I Athletes

Variable	Visit	Women’s Rowing (N = 36) Mean ± SD	Women’s Swimming (N = 20) Mean ± SD	Women’s Gymnastics (N = 9) Mean ± SD	Men’s Swimming (N = 21) Mean ± SD	Men’s Wrestling (N = 15) Mean ± SD	p
Skin carotenoids (Raman intensity counts)	In season	38718 ± 9173	36769 ± 10491	33636 ± 6562	31050 ± 11479	27422 ± 9792
	Out of season	34831 ± 9431	35904 ± 10922	32757 ± 5679	30843 ± 8250	30986 ± 7412
	Change	−3887 ± 7840a	−864 ± 4552a,b	−879 ± 4786a,b	−207 ± 7267a,b	3564 ± 11163b	.035
Body fat (%)	In season	23.3 ± 3.4	23.3 ± 2.7	19.1 ± 2.3	14.4 ± 3.6	14.5 ± 5.2
	Out of season	26.2 ± 3.5	24.3 ± 3.2	19.7 ± 2.1	13.6 ± 3.1	13.0 ± 4.8
	Change	2.8 ± 2.7a	1.1 ± 1.5b	0.6 ± 2.4a,b,c	−0.8 ± 1.8c	−1.4 ± 1.6c	< .001

Means for skin carotenoids, which served as biomarkers of vegetable and fruit intakes, and body fat percentages are presented in-season and out-of-season by team. Mean differences in these variables were assessed by one-way ANOVA followed by Tukey post hoc tests. Superscripts denote significant differences between groups (p ≤ .05).

Mean changes in body composition were also evident from in-season to out-of-season. For women’s teams, mean BF% was 22.7% in-season and 24.7% out-of-season, with Wrow demonstrating the highest BF% at both time points. For men’s teams, mean BF% was 14.4% in-season and 13.4% out-of-season, with Mwr exhibiting greater mean BF% in-season and Mswim when out-of-season. Collectively, the women’s teams demonstrated an increase in mean BF% (Wrow = +2.8%, Wswim = +1.1%, Wgym = +.6%); the men’s teams experienced a decrease in mean BF% (Mswim = −.8%, Mwr = −1.4%) from in-season to out-of-season. Wrow demonstrated a greater increase in BF% from in-season to out-of-season compared to Wswim (p = .03), Mswim (p < .001), and Mwr (p < .001). Mswim demonstrated a decrease in BF% from in-season to out-of-season compared to Wswim (p = .05); Mwr also experienced a decrease in BF% compared to Wswim (p = .02). Changes in skin carotenoids were found to have a moderate inverse association with changes in BF% (r = −.334, p = .001) for the entire cohort, but there were no statistically significant differences within teams.

DISCUSSION

It is well-established that dietary intakes influence the training, performance, and recovery of athletes.¹ However, little is known about the overall dietary patterns of individuals participating in NCAA DI athletics. To our knowledge, this is the first study to document the diet quality and association between changes in vegetable and fruit intakes and body composition within a large cohort of athletes participating in weight-sensitive sports at a NCAA DI university. Our results fill an important gap in knowledge regarding the dietary behaviors of these individuals and provide insight that will inform nutrition intervention in this population.

Based upon guidelines for interpretation of HEI scores using a graded approach, athletes in our cohort would be assigned a grade of C for their diet quality, indicating a dietary pattern inconsistent with adherence to the DGA and suggesting a need for improvement.³⁰ However, whereas overall diet quality remains inadequate, our athletes report varying degrees of adherence to recommendations based upon individual dietary components. For example, though they demonstrate low diet quality for intakes of fatty acids and whole grains, they exhibit greater levels of adherence to guidelines for protein foods and fruit. These results indicate athletes may exhibit suboptimal dietary behaviors for only some components of their overall dietary patterns, and therefore, may need tailored nutrition programming to address specific areas of concern.

Despite suboptimal intakes, our cohort reports higher diet quality than other similar US populations. Total HEI scores are 45.5% higher than 20- to 29-year-old US adults and 12% higher than those in a recent cross-sectional study of US college students, where scores of 48.8 and 63.4, respectively, were reported.^33,34 Differences in diet quality between our cohort and other similar populations may be a result of an emphasis on nutrition for athletic performance and management of body composition within weight-sensitive sports, leading to inherent differences between these athletes and other groups.⁶ However, there remains a lack of available data allowing for comparison of diet quality between our cohort and NCAA athletes participating in a variety of other sports. Future research should evaluate the dietary patterns of a larger, representative sample of athletes to determine diet quality to allow for such a comparison.

In addition to differences that may be characteristic of weight-sensitive athletes, higher diet quality in this cohort may also be indicative of access to resources which may not be available to the general young adult or collegiate student populations. These resources may include provision of food and beverages via access to athlete-specific dining facilities and team meals, or access to nutrition education and counseling with sports RDs. Research suggests access to such resources improves the diet quality of athletes.^35–44

Following the deregulation of the provision of meals and snacks by the NCAA in 2014, many DI collegiate athletic programs, including the program at our university, expanded nutritional services to address the needs of student athletes and reduce barriers to achieving optimal nutrition.⁴⁵ Available resources include prepared team meals and access to fueling stations, which are dining locations positioned near training and competition facilities where convenient grab-and-go foods and beverages are offered. Within Power 5 Conference schools (including members of the Atlantic Coast Conference, Big 10 Conference, Big 12 Conference, PAC-12 Conference, and Southeastern Conference), 81% of universities have more than one fueling station, with the majority serving between 100 to 500 student athletes daily.⁴⁵

Access to environments offering these nutrient-dense meals and snacks prior to or directly after training sessions or performance events provides an important opportunity to supplement student athletes’ diets at our institution. Typical fueling station inventory at our university includes a variety of fruits, ready-to-eat vegetables, low-fat white and chocolate milk, low-fat yogurt, mixed nuts, whole grain granola bars, sandwiches made with whole grain bread, lean proteins, vegetables, and more. Furthermore, athletes at our university receive routine buffet team meals pre- or post-athletic activity containing whole fruit, salad, whole grains, lean proteins, and cooked vegetables. It is possible that the access afforded to these athletes may explain the higher overall diet quality observed in our cohort compared to other populations, as research suggests the food environment influences the quality of dietary patterns in many groups, including college students.^35,36

In addition to providing foods and beverages to athletes, some collegiate teams have hired RDs trained in sports or performance nutrition to offer dietary assessments, evidence-based nutrition education, dietary guidance, and individualized counseling to athletes.^46,47 These interactions with sports RDs improve the diet quality of athletes.^37–44 At our institution, sports RDs are in high demand, but due to understaffing, often do not meet consistently with teams and individual athletes to provide nutrition counseling. The coaching staff often determines frequency of team education from the sports RD; therefore, there are differences in exposure among teams in our cohort. As such, frequency of contact varies from once per week to once per year, and counseling and education from sports RDs are delivered regularly only while athletes are in-season. Although not a primary aim of the current study, we observed that teams with greater frequency of contact with a sports RD trend toward higher diet quality than those with less exposure. Women’s teams, who received RD-led education on a weekly or monthly basis, demonstrate higher diet quality than men’s teams, who received this contact annually. This trend, together with other literature, suggests that when athletes receive education and counseling by a sports RD, there is a positive shift in diet quality, supporting the inclusion of trained nutrition professionals in staffing for collegiate athletics.^37–44 However, although the prevalence of full-time sports RDs in collegiate settings has increased slowly, only 73 schools employ at least one full-time sports RD (6.6% of NCAA member schools).⁴⁶

During the academic year, all athletes in this cohort are provided access to fueling stations, prepared meals, and sports RD-led education, although consistent use of these resources is higher when athletes are in-season than when they are out-of-season. Whereas the impact of this change was not assessed directly, most athletes demonstrate a decrease in skin carotenoids from in-season to out-of-season, indicating a decrease in consumption of vegetables and fruits over this time period.^24,25 Whereas no reference range nor population-specific normative values exist for comparison due to large inter-individual variation in carotenoid status, changes in skin carotenoids have been demonstrated to be responsive to changes in dietary intakes of vegetables and fruits.^24,25 This decrease in produce intakes may be the result of the reduction in the provision of nutrient-dense foods and beverages as well as decreased contact with the sports RD from in-season to out-of-season. This interruption leaves an important gap for student athletes during off-season training and may negatively impact overall diet quality.

Although athletes in this study generally report higher diet quality than similar groups, no teams meet all recommendations, indicating a need for improvement. Further, those on the Mwr team demonstrate poor overall diet quality, with scores indicating a failure to meet guidelines and a grade of F.³⁰ Those on the Mwr team also report lowest HEI component scores for sodium and saturated fats, suggesting greater consumption of foods such as high-fat, high-sodium convenience foods. Additionally, Mwr was the only team that increased skin carotenoids during the off-season, indicating that wrestlers may consume more vegetables and fruits when there is less pressure to manage weight with a highly restrictive dietary pattern. As wrestling is a weight-class sport, these athletes often engage in rapid weight loss prior to weigh-ins to gain a competitive edge over their opponents by having the highest power-to-weight ratio.⁴⁸ This may lead to weight cycling over the course of the season as athletes intentionally manipulate their dietary intakes by employing negative dietary practices such as gradual dieting, fasting, or meal skipping to meet a lower weight class followed by rapid weight regain.^49,50 Unfortunately, no studies that investigate weight management strategies of wrestlers report on individual food groups or overall diet quality.^50–52 As wrestling often hinges on weight management, it is prudent to investigate the relationships between diet quality, body composition, and sport performance for these athletes.

During a high-intensity training season, athletes are likely to have energy expenditure elevated above energy intake, resulting in a negative energy balance and reduction in BF%.⁵³ As athletes shift from high-energy expenditure training in-season to lower frequency and intensity of training out-of-season, a change in energy balance and consequent BF% increase would be expected. This increase was observed within the women’s teams sampled in this study. These data align with previous research, which suggests BF% increases from immediately post-season to the off-season.⁵⁴ A recent systematic review also suggests endurance athletes exhibit greater fat-free mass and lower BF% when in the competition phase of their training.⁵³

It is notable, however, that Mwr and Mswim both reduced BF% from in-season to out-of-season. The body’s homeostatic mechanisms react to food restriction by increasing hunger and suppressing energy expenditure, which ultimately could lead to reduction of non-exercise energy expenditure, and therefore, a withholding of body fat stores despite attempts to lose weight.⁵ The absence of these practices in the off-season may explain the observed change for Mwr. For Mswim, the DXA scan completed while in-season was the first evaluation of body composition the team had received as part of routine analysis; as such, it was the first time these individuals became aware of their BF%. Literature suggests weight awareness is associated with weight loss; therefore, athletes newly exposed to body composition assessments may have been more inclined to engage in weight-regulating habits, which may explain the observed decrease in BF% for this group.⁵⁵

Although athletes in our cohort exhibited normal body composition both in- and out-of-season,⁶ statistically significant differences in mean BF% change between teams indicate athletes participating in different sports may respond uniquely to alterations in training intensity, body composition assessments, and access to nutrition resources. Coupled with observed associations between changes in BF% and carotenoid status, these data suggest nutrition interventions should be tailored to individual teams to address gaps.

To our knowledge, this is the first study to evaluate the association between changes in skin carotenoids and body composition in collegiate athletes. As hypothesized, we identified a statistically significant inverse relationship between change in skin carotenoids and change in BF% for the entire cohort. This result aligns with other literature documenting an inverse relationship between serum carotenoid status and adiposity in both children and adults.^56–58 Whereas we assessed total dietary intakes only at one time point, and cannot determine the relationship between energy density and changes in skin carotenoids or BF%, it is plausible that increases in produce intakes in-season, as evidenced by higher skin carotenoid measures, may be associated with decreases in BF% due to the displacement of energy-dense foods and beverages with nutrient-dense vegetables and fruits.²²

Limitations

Although this study had many strengths, including a large sample size and representation of athletes from multiple NCAA DI sports teams, it was not without limitations. Athletes in this study participated in weight-sensitive sports; therefore, they may not be representative of all DI student athletes, those participating in other sports, or those residing outside the Midwest. In addition, most student athletes in this study were women, and sample sizes for some teams (eg, women’s gymnastics) were low, which may influence generalizability of these results. Because analyses were exploratory in nature, we did not further stratify by sex or control for demographic variables, which may also impact generalizability. Furthermore, evaluation of dietary intakes relied on participant self-report and therefore, was subject to inherent biases such as recall bias. Additionally, the dietary assessment was not taken within the same singular time point for all participants, as some completed the assessment while in-season and others completed it out-of-season; therefore, we cannot make conclusions regarding dietary patterns in relation to seasonal variations. Lastly, although we observed a trend in diet quality between teams receiving differing levels of nutrition education from a sports RD, this study was not designed to address intervention by a sports RD; thus, conclusions regarding this relationship must be interpreted with caution.

Conclusions

Our results indicate that NCAA DI athletes, like most Americans, fall short of meeting the DGA recommendations and demonstrate suboptimal diet quality. In addition, this is the first study to demonstrate that changes in skin carotenoids in a subset of NCAA DI athletes are negatively associated with changes in BF%. In addition, the majority of these athletes had lower skin carotenoids when out-of-season, which indicates lower vegetable and fruit consumption when athletes have less access to sports nutrition counseling and interventions offered during competition season. Taken together, these factors could have a negative impact on overall health as well as sports performance.

Our results also provide evidence to support the role of sports RDs and ready access to nutritious foods year-round for NCAA DI athletes. Universities should consider increasing sports RD staffing to promote access to sports RDs for collegiate athletes. Furthermore, to inform education and counseling of athletes, sports RDs should consider using a standardized metric, such as the HEI, to regularly measure diet quality. These data may identify national trends, areas of concern for specific teams, periods of vulnerability, and may inform future sport nutrition recommendations.