nutrients
Article

Dietary Intakes and Supplement Use in
Pre-Adolescent and Adolescent Canadian Athletes
Jill A. Parnell 1, *, Kristin P. Wiens 2 and Kelly A. Erdman 3
1
2
3

*

Department of Health and Physical Education, Mount Royal University, 4825 Mount Royal Gate SW,
Calgary, AB T3E 6K6, Canada
Department of Behavioral Health and Nutrition, University of Delaware, 026 North College Avenue,
Newark, DE 19716, USA; kwiens@udel.edu
Sport Medicine Centre, University of Calgary, 2500 University Dr NW, Calgary, AB T2N 1N4, Canada;
kerdman@csicalgary.ca
Correspondence: jparnell@mtroyal.ca; Tel.: +1-403-440-8672

Received: 14 July 2016; Accepted: 16 August 2016; Published: 26 August 2016

Abstract: Young athletes experience numerous dietary challenges including growth, training/
competition, unhealthy food environments, and travel. The objective was to determine nutrient
intakes and supplement use in pre-adolescent and adolescent Canadian athletes. Athletes (n = 187)
aged 11–18 years completed an on-line 24-h food recall and dietary supplement questionnaire. Median
energy intake (interquartile range) varied from 2159 kcal/day (1717–2437) in 11–13 years old females
to 2905 kcal/day (2291–3483) in 14–18 years old males. Carbohydrate and protein intakes were
8.1 (6.1–10.5); 2.4 (1.6–3.4) in males 11–13 years, 5.7 (4.5–7.9); 2.0 (1.4–2.6) in females 11–13 years,
5.3 (4.3–7.4); 2.0 (1.5–2.4) in males 14–18 y and 4.9 (4.4–6.2); 1.7 (1.3–2.0) in females 14–18 years g/kg of
body weight respectively. Median vitamin D intakes were below the recommended dietary allowance
(RDA) and potassium was below the adequate intake (AI) for all athlete groups. Females 14–18 years
had intakes below the RDA for iron 91% (72–112), folate 89% (61–114) and calcium 84% (48–106).
Multivitamin-multiminerals, vitamin C, vitamin D, vitamin-enriched water, protein powder, sport
foods, fatty acids, probiotics, and plant extracts were popular supplements. Canadian pre-adolescent
and adolescent athletes could improve their dietary intakes by focusing on food sources of calcium,
vitamin D, potassium, iron, and folate. With the exceptions of vitamin D and carbohydrates during
long exercise sessions, supplementation is generally unnecessary.
Keywords: diet analysis; youth athletes; nutrient intakes; dietary supplements; ergogenic aids

1. Introduction
Young athletes experience numerous nutritional challenges including: Meeting nutrient needs for
growth, training/competition, the maintenance of health, concurrent sporting pursuits, challenging
schedules (school, training, socializing, work, etc.), a lack of knowledge, a reliance on others for the
purchase and preparation of foods, unhealthy eating environments in their locations of training and
competition, and travel [1–4]. Additionally, the eating patterns and attitudes towards foods, set during
adolescence, can impact an individual’s lifelong relationship with food and nutrition [1]. Currently,
targeted recommendations for youth are lacking, forcing the default use of adult recommendations.
Nutrient needs during adolescence are relatively high as compared to adulthood to support
development [5] and these athletes require reliable guidance to ensure health and the prevention of
injuries as they progress in their sporting endeavors. Dietary intakes in young athletes have been
found to be superior to their non-athletic counterparts [6–8]. Conversely, the increased demands of
intense physical activity imply that the consequences of a deficiency are greater in this demographic.
Furthermore, young athletes may have increased nutrient needs suggesting a direct comparison to

Nutrients 2016, 8, 526; doi:10.3390/nu8090526

www.mdpi.com/journal/nutrients

Nutrients 2016, 8, 526

2 of 13

intakes in non-athletes does not accurately represent the physiological impact of their dietary intakes.
In young athletes, nutrients identified as of concern due to insufficient intakes include: Carbohydrates
(especially during exercise), vitamin E, vitamin D, calcium, iron, magnesium, and zinc [5,9–11]. There
is also a concern that the pressures associated with athletic performance can promote eating disorders
with increased rates typically found in adult elite athletes as compared to non-athletes [12]. The role of
sport in fostering eating disorders in youth is controversial with some finding a protective effect in
young, female athletes as compared to non-athletes [13]. Additional investigation is required though it
appears that the level of competition and sport type are critical with an increased risk in elite athletes as
compared to recreational level athletes and those competing in sports that encourage leanness [13,14].
Few studies have evaluated the dietary patterns of young Canadian athletes, particularly those
participating in sport at the community/provincial level. The primary aim of this study was to quantify
dietary intakes in young Canadian athletes, from a wide variety of sports, competing primarily at
the community or provincial level. A secondary aim was to evaluate dietary supplement use in the
contexts of nutrient needs, health, and performance.
2. Materials and Methods
2.1. Participants
Male (n = 84) and female (n = 103) athletes aged 11 to 18 years were recruited from the province of
Alberta through sporting communities and the public school system. The term “athlete” was defined
as competing at the city level or higher and training ≥5 h per week. A sample size of 150 allowed the
reporting of estimates to a margin of error of no more than 8% with a 95% confidence level [15].
2.2. Procedures
Athletes and/or their parents/guardians completed the Food Behaviour Questionnaire (FBQ).
The FBQ is a web-based 24-h diet recall developed by Canadian researchers for diet analysis
in youth [16]. Sport drinks were included in the questionnaire; however, other sport foods and
supplements were not included, as they could not be linked to the Canadian Nutrient File for analysis.
Questions regarding meal timing and training/competition were added to the FBQ. Basal metabolic
rate (BMR) was calculated by the Schofield equation and participants with energy intake/BMR ≤0.89
were classified as low energy reporters [17] and removed from analyses.
A dietary supplement questionnaire [18] was incorporated into the FBQ and included sport
foods, vitamin/mineral supplements, fatty acid supplements, plant extracts, probiotics, and ergogenic
aids. All questionnaires were previously tested for reliability and validity [16,18]; however, the
dietary supplement questionnaire was originally delivered in a face-to-face manner. Consequently, the
electronic format was tested for reliability in a subset of 21 athletes who completed both a paper and
electronic version. Weighted kappa coefficients [19] found questions had fair to moderate agreement
with the exception of frequency of use for vitamin E, vitamin-enriched water, glutamine, sport drinks,
recovery drinks, probiotics, sport gels/gummies, and caffeine pills.
2.3. Ethical Considerations
Individualized access information for the consent form and questionnaire was sent to the
parent’s/guardian’s email account (except for those 18 years of age). Parental consent and athlete assent
was provided electronically prior to commencing the questionnaire. The Mount Royal University
Human Research Ethics Board (2013-19) and a school board (2013 1127 L) approved the study.
2.4. Statistical Analyses
Athletes were categorized based on Dietary Reference Intakes (DRIs): Male 11–13 years, female
11–13 years, male 14–18 years, and female 14–18 years. Estimated energy requirements (EER) were
determined using the Institute of Medicine’s EER equations and an “active” value for physical

Nutrients 2016, 8, 526

3 of 13

activity [20] (pp. 181–182). For macronutrient intakes, absolute values, intakes adjusted for body
weight, and percent of total energy intake were calculated. Micronutrients are presented as absolute
values and the percent of the Recommended Dietary Allowance (RDA) or Adequate Intake (AI). Percent
RDA or AI was calculated by taking the intake for each athlete and dividing it by the established
RDA or AI for that age and gender [21] and multiplying by 100. Supplement use was quantified as
the percent of respondents who consumed the supplement Regularly, Occasionally (“Specific Times”
or “I’ve Tried It”), and Never (“Never” or “Unfamiliar”). Data was checked for normality using the
Shapiro-Wilk test. Differences for macronutrients in the percent of total calories and g/kg/body weight
and micronutrient percent of Recommended Dietary Allowance (%RDA) or Adequate Intake (%AI) [21]
were determined using a Kruskal–Wallis non-parametric test and difference between genders and
age groups were assessed using Dunn’s test for post-hoc pairwise comparisons. In cases where the
data was normally distributed, a one-way ANOVA with a Bonferroni post-hoc comparison within age
and gender was also calculated. Differences in percent of athletes meeting Canada’s Food Guide [22]
servings and dietary supplement/ergogenic aids use were determined using a Pearson’s Chi-squared
test and the effect size reported as V = Cramer’s V. A p-value of < 0.05 was considered to be statistically
significant. All analyses were performed using SPSS version 22 (IBM Corporation, Armonk, NY, USA)
and Stata 14 (StataCorp, College Station, TX, USA).
3. Results
3.1. Participant Characteristics
The FBQ was completed by 187 participants, however, two females 11–13 years, two males
11–13 years, 12 females 14–18 years, and three males 14–18 years were identified as low-energy
reporters and were removed from the analyses. Descriptive characteristics for the remaining
168 participants who completed the FBQ are presented in Table 1. Eight percent of young females, 15%
of older females, 4% of young males, and 0% of older males reported trying to lose weight (p = 0.030;
V = 0.204), whereas 3% of young females, 0% of older females, 15% of young males, and 42% of
older males reported trying to gain weight (p < 0.001; V = 0.381). Energy intakes as a percent of EER
were 98% (83–125) in 11–13 years old males, 91% (76–112) in 11–13 years old females, 85% (70–107)
in 14–18 years old males, and 89% (73–104) in 14–18 years old females; there were no statistically
significant differences between the groups.
3.2. Nutrient Intakes
Macronutrient intakes are presented in Table 2. Younger males had greater carbohydrate intakes
based on body weight as compared to older males (p = 0.001) and older females (p < 0.001). Protein
intakes based on body weight were highest in young males and greater as compared to older females
(p < 0.001) and older males (p = 0.046), however the dietary assessment did not include protein
supplements. The percent of calories coming from sugar and fats was consistent across all groups,
however, based on body weight, young males had greater intakes of total fat as compared to older
females (p < 0.001).
Micronutrient intakes are described in Table 3. Athletes’ median intakes met or exceeded the RDA
for all vitamins with the exception of vitamin D, folate (14–18 years females) and vitamin A (females
11–13 years and males 14–18 years). Females did not consume the RDA for calcium and older females
did not meet the RDA for iron. Athletes did not meet the AI for potassium. Sodium intakes exceeded
the upper limit in 89% of males 11–13 years, 65% of females 11–13 years, 83% of males 14–18 years,
and 69% of females 14–18 years (p = 0.061; V = 0.209).
Servings according to Eating Well with Canada’s Food Guide can be found in Table 4. Differences
between the groups were noted in milk and alternatives where older females had the fewest percent of
participants meeting the recommendation (p = 0.010; V = 0.259) and in the meat and alternatives where
older males had a lower percent meeting the recommendations (p = 0.002; V = 0.294).

Nutrients 2016, 8, 526

4 of 13

Table 1. Descriptive characteristics.
Descriptive Characteristics
Participants
Age years
Weight kg
Height m
BMI kg/m2
Level of Competition
Club
Provincial
National
International
Sport Classification
Endurance
Intermittent
Aesthetic
Power/Strength
Response Rate
Total Assigned ID
Food Recall
Low Energy Reporters
Dietary Supplements

All

Males 11–13 Years

Females 11–13 Years

Males 14–18 Years

Females 14–18 Years

168
14 (13–16)
56 (12.9)
1.7 (1.6–1.8)
19.9 (18.3–21.7)

26
12 (11–13)
47 (9.9)
1.6 (1.5–1.6)
18.5 (16.9–19.9)

37
13(12–13)
46 (8.7)
1.6 (1.5–1.6)
18.7 (17.7–20.6)

53
15 (15–16)
67 (12.2)
1.8 (1.8–1.9)
21.2 (19.6–22.2)

52
15 (14.5–17)
57 (7.2)
1.7 (1.6–1.7)
20.5 (19.0–21.9)

55
60
33
20

7
16
0
3

14
19
3
1

21
10
15
7

13
15
15
9

42
69
24
33

5
7
1
13

9
16
11
1

13
26
1
13

15
20
11
6

2 (7%)

2 (5%)

3 (5%)

12 (19%)

327
187 (57%)
19 (10%)
173 (53%)

Descriptive characteristics are provided for all participants that reported adequate energy intakes on their Food Behaviour Questionnaire. Age, height, and BMI are median
(interquartile range) and weight is mean (standard deviation). Values in “[]” under “Response Rate“ refer to the percent of participants who completed the food recall and dietary
supplement portions of the questionnaire, as well as those who were removed because they were low energy reporters [17].

Nutrients 2016, 8, 526

5 of 13

Table 2. Reported energy and macronutrient intakes.
Nutrient

Male 11–13 (n = 26)

Female 11–13 (n = 37)

Male 14–18 (n = 53)

Female 14–18 (n = 52)

Energy kcal/day
Carbohydrates g/day
Carbohydrates %kcal *
Carbohydrates g/kg BW
Fibre g
Sugar g
Sugar % kcal *
Protein g/day
Protein %kcal
Protein g/kg BW
Fat g/day
Fat %kcal *
Fat g/kg BW
Saturated Fat g
Saturated Fat %kcal *
MUFAs g
PUFAs g
Trans Fat g
Cholesterol g

2745 (2165–3555)
386 (282–442)
56 (45–61)
8.1 (6.1–10.5)
25 (20–35)
144 (115–191)
24 (17–28)
114 (82–162)
16 (13–20)
2.4 (1.6–3.4)
92 (79–128)
33 (26–38)
2.2 (1.4–2.7)
33 (27–43)
11 (9–13)
29 (23–42)
13 (9–23)
0.5 (0.1–1.1)
315 (174–484)

2159 (1717–2437)
264 (207–344)
54 (49–59)
5.7 (4.5–7.9) a
19 (14–28)
93 (71–146)
20 (16–26)
94 (67–112)
16 (15–19)
2.0 (1.4–2.6)
72 (53–95)
31 (26–36)
1.7 (1.2–2.1)
23 (18–32)
10 (8–13)
25 (16–33)
11 (7–18)
0.2 (0.1–0.9)
253 (105–388)

2905 (2291–3483)
353 (282–464)
52 (42–56)
5.3 (4.3–7.4) b
25 (18–33)
146 (109–183)
20 (16–26)
123 (104–159)
17 (15–21)
2.0 (1.5–2.4) b
108 (88–133)
33 (28–40)
1.7 (1.3–2.1)
38 (28–47)
11 (9–14)
35 (29–42)
17 (13–24)
0.5 (0.2–0.9)
408 (271–629)

2177 (1764–2540)
281 (218–333)
52 (47–59)
4.9 (4.4–6.2) c
23 (19–29)
106 (81–145)
22 (17–25)
97 (76–113)
17 (14–20)
1.7 (1.3–2.0) c
79 (60–102)
33 (28–39)
1.4 (1.1–1.8) c
24 (17–34)
11 (8–14)
23 (18–30)
12 (9–18)
0.1 (0–0.5)
255 (176–393)

p

0.435
<0.001

0.741
0.660
<0.001
0.700
0.002
0.723

Intakes are presented as median (interquartile range). BW, body weight; kcal, kilocalories; MUFAs, monounsaturated fatty acids; and PUFA, polyunsaturated fatty acids. Significant
differences in %kcal and g/kg/BW were determined by a Kruskal–Wallis non-parametric test and a difference between genders within age group; b difference between age group
within gender; and c difference between genders within different age groups were assessed using Dunn’s test for post-hoc pairwise comparisons. Variables with * are normally
distributed thus an ANOVA was also performed and the differences remained non-significant.

Nutrients 2016, 8, 526

6 of 13

Table 3. Micronutrient intakes from food sources.
Nutrient

Male 11–13 (n = 26)

Females 11–13 (n = 37)

Males 14–18 (n = 53)

Female 14–18 (n = 52)

p

Thiamin mg/day
%RDA

1.9 (1.4–2.3)
203 (140–240)

1.4 (1.0–1.8)
155 (112–204)

2.1 (1.6–3.0)
175 (137–246)

1.6 (1.1–2.1)
156 (113–213)

0.073

Riboflavin mg/day
%RDA

2.9 (2.2–3.9)
317 (248–434)

2.1 (1.6–3.0)
237 (182–336) a

3.4 (2.6–4.1)
258 (200–314) b

2.1 (1.4–2.7)
207 (143–271) a,c

<0.001

Niacin mg/day
%RDA

40 (30–59)
335 (250–494)

33 (24–43)
274 (200–359)

45 (37–63)
282 (230–393)

37 (24–45)
264 (173–325) c

0.024

Vitamin B6 mg/day
%RDA

2.1 (1.4–3.2)
208 (142–315)

1.3 (1.0–1.9)
133 (104–193) a

2.4 (1.6–3.1)
185 (127–238)

1.6 (1.2–2.3)
132 (103–192) a,c

0.002

Folate µg/day
%RDA

412 (314–651)
138 (105–217)

309 (260–382)
103 (87–127) a

486 (339–642)
122 (85–161)

357 (244–457)
89 (61–114) a,c

<0.001

Vitamin B12 µg/day
%RDA

5.5 (3.6–8.4)
303 (198–465)

4.0 (2.5–5.9)
223 (137–326)

7.5 (4.2–10.3)
313 (174–429)

3.5 (2.3–5.6)
147 (95–233) a,b,c

<0.001

Vitamin C mg/day
%RDA

160 (65–262)
356 (143–583)

97 (54–141)
216 (119–313)

143 (81–279)
191 (107–372)

164 (105–240)
252 (161–369)

0.187

Vitamin D µg/day
%RDA

8.4 (4.7–16.4)
56 (31–109)

4.3 (1.4–7.4)
29 (10–49) a

9.2 (5.7–15.2)
62 (38–101) c

3.1 (1.7–6.3)
21 (11–42) a,c

<0.001

933 (651–1191)

463 (287–842)

864 (702–1121)

697 (353–1065)

156 (108–199)

77 (48–140) a

96 (78–125) b

100 (50–152) c

0.005

1419 (1113–2233)
109 (86–172)

1040 (715–1492)
80 (55–115) a

1686 (1169–2251)
130 (90–173) c

1090 (625–1377)
84 (48–106) a,c

<0.001

Iron mg/day
%RDA

18 (12–20)
228 (150–250)

13 (10–17)
166 (130–211)

18 (15–22)
165 (137–195)

14 (11–17)
91 (72–112) a,b,c

<0.001

Zinc mg/day
%RDA

14 (10–16)
177 (121–204)

10 (7–13)
121 (88–167) a

15 (12–18)
138 (107–166)

9 (7–13)
103 (79–140) a,c

<0.001

Potassium mg/day
%AI

3934 (3156–5150)
87 (70–114)

2534 (2125–3716)
56 (47–83) a

4292 (3483–5012)
91 (73–107) c

3240 (2274–3940)
69 (48–84) a,c

<0.001

Sodium mg/day
%AI

3476 (2648–4573)
232 (177–305)

2701 (2089–3388)
180 (139–226) a

3651 (2967–4676)
243 (198–312) c

2928 (2144–3564)
195 (143–238) a

<0.001

Vitamin A RAE
µg/day
%RDA
Calcium mg/day
%RDA

Intakes are median (interquartile range). Percent RDA or AI for each athlete was calculated by taking their intake and dividing it by the established RDA or AI for that age and
gender [21] and multiplying by 100. Significant differences in percent RDA or AI were determined by a Kruskal–Wallis non-parametric test and a difference between genders within age
group; b difference between age group within gender; and c difference between genders within different age groups were assessed using Dunn’s test for post-hoc pairwise comparisons.

Nutrients 2016, 8, 526

7 of 13

Table 4. Canada’s Food Guide servings.
Nutrient
Vegetables and Fruits
Met %
Grains
Met %
Milk and Alt.
Met %
Meat and Alt.
Met %
Other
Met %

Male 11–13 (n = 26)

Female 11–13 (n = 37)

Male 14–18 (n = 53)

Female 14–18 (n = 52)

6.5 (4.0–10.0)
62 (n = 16)
9.0 (6.0–11.0)
81 (n = 21)
3.0 (3.0–6.0)
77 (n = 20)
3.0 (1.0–3.0)
89 (n = 23)
4.0 (2.0–6.0)
N/A

4.0 (3.0–7.0)
35 (n = 13)
6.0 (4.0–9.0)
65 (n = 24)
3.0 (2.0–4.0)
57 (n = 21)
3.0 (2.0–3.0)
89 (n = 33)
3.0 (2.0–6.0)
N/A

7.0 (4.0–9.0)
40 (n = 21)
8.0 (6.0–11.0)
68 (n = 36)
4.0 (3.0–6.0)
76 (n = 40)
3.0 (2.0–5.0)
59 (n = 31)
4.0 (3.0–6.0)
N/A

7.0 (5.0–9.0)
54 (n = 28)
7.0 (5.0–8.0)
65 (n = 34)
2.0 (1.0–3.5)
48 (n = 25)
3.0 (2.0–3.0)
77 (n = 40)
3.5 (2.0–6.5)
N/A

p
0.093
0.516
0.010
0.002

Eating Well with Canada’s Food Guide [22] servings are presented as median (interquartile range). Percent met was calculated as the percent of athletes meeting the minimum
recommended daily amounts. Significant differences in the percent of athletes in the groups meeting the minimum recommendations were determined by a Pearson’s Chi-squared test.

Nutrients 2016, 8, 526

8 of 13

3.3. Supplements
The use of dietary supplements and ergogenic aids is presented as those who consume the
supplement regularly, occasionally, or never (Table 5). Given the broad definition of dietary
supplements and the inclusion of occasional use over the past 3 months, 100% of athletes reported
some usage. Multivitamin-multiminerals, vitamin C, vitamin D, sport bars, and protein powders
were the most commonly consumed supplements on a regular basis. Supplements athletes frequently
reported using occasionally included vitamin C, vitamin-enriched water, protein powders, sport bars
and drinks, plant extracts, and gels/gummies. When supplement use was analyzed according to
gender alone, differences were noted in fatty acid intakes with 17% of males reporting regular use,
5% occasional use and 78% never, whereas females reported regular use at 8%, occasional use at 15%
and never at 77% (p = 0.045; V = 0.189). Furthermore, 18% of males used sport drinks regularly, 69%
occasionally and 13% never as compared to females at 7% regularly, 70% occasionally, and 23% never
(p = 0.040; V = 0.193). Analysis by age groups 11–13 years and 14–18 years found increased use of
protein powder in the older age group with regular use 18%, occasional 45%, and never 37% vs. 10%
regular, 23% occasional, and 68% never in 11–13 years (p = 0.001; V = 0.296). None of the athletes
reported regular use of energy drinks, however, 14–18 years old had occasional use at 27% vs. 3% in
11–13 years (p < 0.001; V = 0.294). There were no other significant differences between gender or age
groups in supplement use.
Table 5. Dietary supplements and ergogenic aids.
Supplement %
Athletes

Males 11–13 (n = 26)

Females 11–13 (n = 36)

Males 14–18 (n = 52)

Females 14–18 (n = 59)

R

O

N

R

O

N

R

O

N

R

O

N

p

MVMM
B Vitamins
Vitamin C
Vitamin E
Vitamin D *
Vitamin Water
Iron
Calcium
Magnesium
Protein Powder
Beta Alanine
BCAA
Glutamine
Glucosamine
Fatty Acids
Sport Drink
Recovery Drink
Energy Drink
Sport Bar
Creatine
Caffeine
Gel/Gummy
Plant Extracts
Probiotics

46
0
15
0
19
8
0
0
0
12
4
4
4
0
19
15
15
0
15
4
0
8
4
4

15
8
23
4
0
39
0
0
4
19
0
0
0
0
8
65
8
4
46
0
0
46
31
19

39
92
62
96
81
54
100
100
96
69
96
96
96
100
73
19
77
96
39
96
100
46
65
77

36
6
19
3
19
3
3
6
3
8
0
3
0
0
17
8
0
0
14
0
0
0
3
3

19
6
31
11
3
61
3
8
3
25
0
0
0
0
11
69
14
3
69
0
0
47
39
19

44
89
50
86
78
36
94
86
94
67
100
97
100
100
72
22
86
97
17
100
100
53
58
78

40
6
27
2
14
10
2
8
2
25
0
2
0
2
15
19
4
0
33
2
0
2
2
0

19
17
23
6
0
46
6
10
6
42
6
6
4
4
4
71
23
33
50
8
2
29
31
14

40
77
50
92
87
44
92
83
92
33
94
92
96
94
81
10
73
67
17
90
98
69
67
87

22
3
19
3
24
7
5
3
0
12
0
3
0
0
3
7
5
0
25
2
0
0
3
0

27
10
27
12
0
48
12
7
2
48
0
2
2
5
17
70
17
22
51
0
0
37
37
20

51
86
54
85
76
46
83
90
98
41
100
95
98
95
80
24
78
78
24
98
100
63
59
80

0.346
0.482
0.862
0.747
0.453
0.629
0.251
0.471
0.735
0.004
0.047
0.598
0.230
0.495
0.090
0.264
0.109
0.001
0.110
0.092
0.505
0.079
0.968
0.559

Dietary supplement use is presented as percent of athletes who completed the dietary supplement portion
of the questionnaire (n = 173). * Vitamin D was determined from responses to “Other Vitamins”. MVMM,
multivitamin-multimineral; BCAA, branched chain amino acids; R, regularly; O, occasionally; and N, never.
Significant differences in the percent of athletes in the groups consuming the supplement were determined by a
Pearson’s Chi-squared test.

4. Discussion
This research is significant as it analyzes dietary intakes and supplement use across a broad
range of sport types in a cohort of younger, understudied athletes. Studies focused on a single sport
are extremely valuable to the cohort of athletes they represent, however, are less able to provide
information regarding general nutrition concerns.

Nutrients 2016, 8, 526

9 of 13

4.1. Overall Diet Quality and Energy Intakes
Adolescents typically adhere to a dietary pattern that is energy dense, however, low in
nutrients [23]. Conversely, studies do report improved dietary intakes in adolescent athletic
populations as compared to their sedentary peers [6–8]. Athletes have increased rates of disordered
eating as compared to non-athletes, however, this concerns is more applicable to older athletes
competing at higher levels than the majority of our sample [12]. Notably, the decline in diet quality in
our female 14–18 years cohort, as compared to other groups, could be indicative of a trend towards
increased rates of disordered eating; coaches and parents should carefully monitor this group. When
athletes self-reported on the quality of their diet, 3% thought their diet was poor, 72% rated their diet
as average, and 25% selected excellent.
Assessment of the athletes’ Canada’s Food Guide servings can provide an understanding of
overall diet quality, however, Canada’s Food Guide does not take into consideration high levels of
physical activity. Consequently, it is possible that Table 4 underestimates the percentage of athletes
consuming insufficient numbers of servings. It can reasonably be concluded that milk and alternatives
is a food category of concern for young female athletes, a risk that increases with age. Furthermore, all
athletes need to be encouraged to consume more vegetables and fruits. Another factor, potentially
limiting performance in some athletes, may be inadequate intakes of whole grains, as grains are often
good sources of carbohydrates, food folic acid, and iron. The relatively high contribution of sugars and
saturated fats to total calories and servings from the “other” category, suggest young athletes need to
focus on healthier choices and reducing processed and fast foods. A conclusion further supported by
the high sodium intakes.
Energy intakes are slightly lower than the EER. An energy deficit is commonly reported in
athletes [5,24,25], however, it is extremely difficult to accurately assess energy needs in young
athletes [1] and self-reported dietary records are limited. Furthermore, BMI data indicates that
underweight is not a prominent concern in this cohort of athletes.
4.2. Macronutrients
It is difficult to assess the adequacy of macronutrient intakes in young athletes due to a lack of
recommendations and a default to adult values [26,27]. Carbohydrate recommendations based on
body weight rather than percent of total calories are thought to best reflect athlete needs and range
from 3 to 12 g/kg/BW depending on exercise load [28]. Carbohydrate intakes meet the minimum
requirements in all our athlete groups. Importantly, when carbohydrate intakes were analyzed by sport
type, endurance and intermittent athletes had median intakes of 5.5 g/kg/BW; whereas, aesthetic
and power athletes had higher intakes at 6.2 g/kg/BW and 5.8 g/kg/BW respectively. Therefore, it
may be advisable to emphasize carbohydrates for young endurance athletes. Inadequate carbohydrate
intake in young athletes has been noted in other studies [5,11,26,27]. Dietary fibre intakes did not meet
recommendations, suggesting that information on the quantity and quality of carbohydrates should
be provided.
Protein recommendations have recently increased and range from 1.2 to 2.0 g/kg/BW depending
on the type and amount of physical activity [29]. Furthermore, it has been estimated that protein
intakes of 1.5 g/kg BW are required for nitrogen balance in young sprinters [30] and can, therefore, be
assumed sufficient for most young athletes. Average protein intakes, from food alone, exceeded the
upper recommendation for performance in all groups except 14–18 years old females, suggesting that
this is not a nutrient of concern for young Canadian athletes; a finding supported by others [26,27].
Data in young, elite Canadian soccer players reports average protein intakes of 1.8 g/kg/BW [5].
Indeed, even elite, young female figure skaters reported an average protein intake of 1.2 g/kg/BW,
despite total caloric intakes 44% less than their estimated needs [25]. It has been suggested that
protein intakes are generally adequate or excessive because protein is overvalued among coaches and
athletes [9,31].

Nutrients 2016, 8, 526

10 of 13

Dietary fats ranged from 31% to 33% of total calories, which is at the high-end of the recommended
25%–35% [20]. Intakes of at least 30% have been consistently reported in adolescent athletes [1].
Young athletes may benefit from consuming fewer calories from fat and increasing calories from
carbohydrates [11]. Conversely, if a young athlete were struggling to meet their caloric needs, healthy
fats would be the most energy dense options.
4.3. Micronutrients
Athletes may have a greater need for select micronutrients, however, no widely accepted values
are available [29]. Athletes met or exceeded the micronutrient recommendations in most cases. Notably,
however, females between 14 and 18 years tended to have the lowest intakes relative to other groups,
highlighting this group as higher risk. Importantly, when considering the micronutrient values as
determined from 24-h recalls there is the possibility of underreporting. Underreporting was addressed
in the methods by identifying low energy reporters, however could still be present to a lesser degree in
the remaining sample, possibly inflating nutrient deficiencies.
Of particular apprehension in young athletes, especially females, is their ability to meet the
recommendations for the bone-building nutrients such as vitamin D, calcium, and phosphorus [25].
Low bone mineral density has been reported in adolescent, female athletes, primarily those with
amenorrhea [32]. Our results indicate vitamin D and calcium are of concern, with a high percentage
of female athletes not meeting the RDA for these nutrients. Gibson et al. [5] also highlight vitamin D
and calcium as nutrients of concern for young Canadian soccer players. The inadequate intakes of
bone-related nutrients in our population may be associated with lower intakes of milk and alternatives.
Iron and folate (females 14–18 years) were also identified as nutrients where intakes often did
not meet the RDA. Deficiencies in either of these nutrients can promote anemia, which can cause
fatigue and suboptimal athletic performance [33]. Young female athletes are at a higher risk than
their male counterparts for iron deficiencies due to losses from menses and lower energy intakes, and
compared to their sedentary peers due to the increased requirements for intense training [29,33,34].
Diet assessments in other athletic populations also find inadequate intakes for iron and/or folate
in young female athletes [5,10,11,25]. In Gibson et al. [5] although only 6% of athletes had iron
intakes below the EAR, 89% had serum ferritin levels below 35 µg/L, a level thought to negatively
impact performance.
Potassium was another nutrient where athletes did not meet the AI. Potassium has a role in
muscle and nerve function and, consequently, is related to athletic performance. Although it is
questionable whether intakes in the range noted here could negatively impact performance, it would
still be prudent for athletes to increase their vegetable and fruit intakes to meet the Canada’s Food
Guide recommendations, as these foods are often good sources of potassium.
4.4. Supplements
Sport nutrition professionals agree that athletes should not use dietary supplements to compensate
for a poor diet but rather consume whole foods to meet their nutrient needs. Only when this is not
feasible should athletes rely on supplements [1,33].
Protein supplements were popular in our cohort; yet appear to be unnecessary given the
high dietary intakes. Additionally, the need for a multivitamin-multimineral, vitamin C, and
vitamin-enriched waters is questionable in the context of their nutrient intakes from food alone. Vitamin
D supplementation is often recommended for athletes living at northern latitudes or training indoors
and levels should be carefully monitored in young Canadian athletes to determine if supplementation
is necessary [29]. Although calcium has been identified as a nutrient of concern in young female
athletes, dietary changes rather than supplementation is recommended. Sport drinks, gummies, and
gels could be justified during longer training sessions, as insufficient carbohydrate during exercise
has been identified as a weakness in some young athletes [27]. Athletes should be cautious, however,
to use these products only as needed and monitor calorie and sugar intakes [35]. Probiotics have the

Nutrients 2016, 8, 526

11 of 13

potential to reduce gastrointestinal symptoms and respiratory illnesses in athletes, however, additional
research is needed to confirm these benefits and determine the types and effective dose [36].
Protein supplementation and energy drink consumption increased with age, a trend that we
have previously reported [18]. Furthermore, others have found that dietary supplement use in
youth increases with age [37]. Additional research is required to determine the reasons for these
trends. However, it should be noted that the older athletes were also more likely to compete at a
higher level; thus, the level of competition could be a factor, as these products are often viewed as
performance-enhancing. Regardless, energy drink consumption is concerning in this demographic
as they are contraindicated for those under the age of 18 years [35]. Male athletes were also more
likely to use sport drinks. The reason for this is unclear, however, it may be linked to an overall
concern regarding energy intake in females, as they were also more likely to be low energy reporters.
Alternatively, we have previously demonstrated that young, Canadian male athletes are more likely
than their female counterparts to use supplements for overall athletic performance [11] and others
have found increased use in young males [37].
Our results are limited in that they are based on a single 24-h food recall and there is low reliability
for a few dietary supplements, however, these limitations are somewhat offset by the large sample
size. Additionally, we did not assess physical stages of maturation and it must be acknowledged
that young athletes develop at different rates with considerable variation likely within the groups.
The analysis was based on DRI recommendations; however, these are generalized and not specific to
the individual or their athletic pursuits. Furthermore, multiple comparisons were made with a 5%
level of significance, so it could be expected that up to 5% of results could be due to chance alone.
Although caution should be taken when interpreting the findings, the reporting of all potentially
important associations was deemed to outweigh the cost of a false positive in this case. Future research
should be conducted to either refute or corroborate the findings.
5. Conclusions
Athlete support personnel should focus on food sources of vitamin D and calcium, iron, and
folate (females). Supplementation is generally unnecessary, with the possible exceptions of vitamin D
and iron, under physician supervision. Carbohydrate supplements should be emphasized to balance
depletion versus overconsumption. Our research is novel in that, to our knowledge, it provides the
first large scale, multi-sport assessment of dietary intakes in pre-adolescent and adolescent Canadian
athletes. The information gained can be practically used to inform athlete support personnel regarding
common trends and areas of nutritional concern in young athletes.
Acknowledgments: The Canadian Foundation of Dietetic Research funded the project. The authors would like to
thank Jodi Siever for her assistance with the statistical analysis. Funds for covering the costs to publish in open
access were provided by Mount Royal University.
Author Contributions: J.A.P., K.P.W., and K.A.E. conceived and designed the experiments; J.A.P. performed the
experiments; J.A.P. and K.P.W. analyzed the data; J.A.P., K.P.W., and K.A.E. wrote the paper.
Conflicts of Interest: The authors declare no conflict of interest. The founding sponsors had no role in the design
of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, and in the
decision to publish the results.

References
1.

2.
3.

Desbrow, B.; McCormack, J.; Burke, L.M.; Cox, G.R.; Fallon, K.; Hislop, M.; Logan, R.; Marino, N.;
Sawyer, S.M.; Shaw, G.; et al. Sports Dietitians Australia Position Statement: Sports nutrition for the
adolescent athlete. Int. J. Sport Nutr. Exerc. Metab. 2014, 24, 570–584. [CrossRef] [PubMed]
Rosenbloom, C.A.; Loucks, A.B.; Ekblom, B. Special populations: The female player and the youth player.
J. Sports Sci. 2006, 24, 783–793. [CrossRef] [PubMed]
Thomas, M.; Nelson, T.F.; Harwood, E.; Neumark-Sztainer, D. Exploring parent perceptions of the food
environment in youth sport. J. Nutr. Educ. Behav. 2012, 44, 365–371. [CrossRef] [PubMed]

Nutrients 2016, 8, 526

4.

5.
6.
7.

8.

9.
10.

11.
12.

13.

14.

15.
16.

17.

18.
19.
20.
21.
22.
23.

24.

12 of 13

Walsh, M.; Cartwright, L.; Corish, C.; Sugrue, S.; Wood-Martin, R. The body composition, nutritional
knowledge, attitudes, behaviors, and future education needs of senior schoolboy rugby players in Ireland.
Int. J. Sport Nutr. Exerc. Metab. 2011, 21, 365–376. [CrossRef] [PubMed]
Gibson, J.C.; Stuart-Hill, L.; Martin, S.; Gaul, C. Nutrition status of junior elite Canadian female soccer
athletes. Int. J. Sport Nutr. Exerc. Metab. 2011, 21, 507–514. [CrossRef] [PubMed]
Garcin, M.; Doussot, L.; Mille-Hamard, L.; Billat, V. Athletes’ dietary intake was closer to French RDA’s than
those of young sedentary counterparts. Nutr. Res. 2009, 29, 736–742. [CrossRef] [PubMed]
Cavadini, C.; Decarli, B.; Grin, J.; Narring, F.; Michaud, P.-A. Food habits and sport activity during
adolescence: Differences between athletic and non-athletic teenagers in Switzerland. Eur. J. Clin. Nutr. 2000,
54, S16–S20. [CrossRef] [PubMed]
Croll, J.K.; Neumark-Sztainer, D.; Story, M.; Wall, M.; Perry, C.; Harnack, L. Adolescents involved
in weight-related and power team sports have better eating patterns and nutrient intakes than
non-sport-involved adolescents. J. Am. Diet. Assoc. 2006, 106, 709–717. [CrossRef] [PubMed]
Juzwiak, C.R.; Amancio, O.M.S.; Vitalle, M.S.S.; Pinheiro, M.M.; Szejnfeld, V.L. Body composition and
nutritional profile of male adolescent tennis players. J. Sports Sci. 2008, 26, 1209–1217. [CrossRef] [PubMed]
Koehler, K.; Braun, H.; Achtzehn, S.; Hildebrand, U.; Predel, H.-G.; Mester, J.; Schanzer, W. Iron status in elite
young athletes: Gender-dependent influences of diet and exercise. Eur. J. Appl. Physiol. 2012, 112, 513–523.
[CrossRef] [PubMed]
Papadopoulou, S.; Papadopoulou, S.; Gallos, G. Macro- and mico-nutrient intake of adolescent Greek female
volleyball players. Int. J. Sport Nutr. Exerc. Metab. 2002, 12, 73–80. [CrossRef] [PubMed]
Joy, E.; Kussman, A.; Nattiv, A. 2016 update on eating disorders in athletes: A comprehensive narrative
review with a focus on clinical assessment and management. J. Sports Med. 2016, 50, 154–162. [CrossRef]
[PubMed]
Rosendahl, J.; Bormann, B.; Aschenbrenner, K.; Aschenbrenner, F.; Strauss, B. Dieting and disordered eating
in German high school athletes and non-athletes. Scand. J. Med. Sci. Sport 2009, 19, 731–739. [CrossRef]
[PubMed]
Kong, P.; Harris, L.M. The sporting body: Body image and eating disorder symptomatology among female
athletes from leanness focused and nonleannes focused sports. J. Psychol. 2015, 149, 141–160. [CrossRef]
[PubMed]
Russ Lenth’s Power and Sample-Size Page. Available online: http://homepage.stat.uiowa.edu/~rlenth/
Power/ (accessed on 29 July 2015).
Hanning, R.M.; Royall, D.; Toews, J.E.; Blashill, L.; Wegener, J.; Driezen, P. Web-Based Food Behaviour
Questionnaire: Validation with grades six to eight students. Can. J. Diet. Pract. Res. 2009, 70, 172–178.
[CrossRef] [PubMed]
Kontogianni, M.D.; Farmake, A.-E.; Vidra, N.; Sofrona, S.; Magkanari, F.; Yannakoulia, M. Associations
between lifestyle patterns and body mass index in a sample of Greek children and adolescents. J. Am.
Diet. Assoc. 2010, 110, 215–221. [CrossRef] [PubMed]
Wiens, K.; Erdman, K.A.; Stadnyk, M.; Parnell, J.A. Dietary supplement usage, motivation, and education in
young Canadian athletes. Int. J. Sport Nutr. Exerc. Metab. 2014, 24, 613–622. [CrossRef] [PubMed]
Viera, A.J.; Garrett, J.M. Understanding interobserver agreement: The Kappa Statistic. Fam. Med. 2005, 37,
360–363. [PubMed]
Institute of Medicine. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol,
Protein and Amino Acids; National Academies Press: Washington, DC, USA, 2005; pp. 181–182.
Dietary Reference Intakes Tables and Application. Available online: http://iom.nationalacademies.org/
Activities/Nutrition/SummaryDRIs/DRI-Tables.aspx (accessed on 25 November 2015).
Eating Well with Canada’s Food Guide. Available online: http://www.hc-sc.gc.ca/fn-an/food-guidealiment/index-eng.php (accessed on 25 November 2015).
Diethelm, K.; Jankovic, N.; Moreno, L.A.; Huybrechts, I.; De Henauw, S.; De Vriendt, T.; Gonzalez-Gross, M.;
Leclercq, C.; Gottrand, F.; Gilbert, C.G.; et al. Food intake of European adolescents in the light of different
food-based dietary guidelines: Results of the HELENA (Healthy Lifestyle in Europe by Nutrition in
Adolescence) Study. Public Health Nutr. 2012, 15, 386–398. [CrossRef] [PubMed]
Aerenhouts, D.; Deriemaeker, P.; Hebbelinck, M.; Clarys, P. Energy and macronutrient intake in adolescent
sprint athletes: A follow-up study. J. Sports Sci. 2011, 29, 73–82. [CrossRef] [PubMed]

Nutrients 2016, 8, 526

25.

26.
27.

28.
29.

30.

31.
32.

33.
34.
35.
36.
37.

13 of 13

Dwyer, J.; Eisenberg, A.; Prelack, K.; Song, W.O.; Sonneville, K.; Ziegler, P. Eating attitudes and food intakes
of elite adolescent female figure skaters: A cross sectional study. J. Int. Soc. Sports Nutr. 2012, 9, 1–7.
[CrossRef] [PubMed]
Nikic, M.; Jakovljevi, S.; Pediši, Ž.; Venus, D.; Šatali, Z. Adequacy of nutrient intakes in elite junior basketball
players. Int. J. Sport Nutr. Exerc. Metab. 2014, 24, 516–523. [CrossRef] [PubMed]
Baker, L.B.; Heaton, L.E.; Nuccio, R.P.; Stein, K.W. Dietitian-observed macronutrient intakes of young skill
and team-sport athletes: Adequacy of pre, during, and postexercise nutrition. Int. J. Sport Nutr. Exerc. Metab.
2014, 24, 166–176. [CrossRef] [PubMed]
Burke, L.M.; Hawley, J.A.; Wong, S.H.S.; Jeukendrup, A.E. Carbohydrates for training and competition.
J. Sports Sci. 2011, 29, S17–S27. [CrossRef] [PubMed]
Thomas, D.T.; Erdman, K.A.; Burke, L.M. Position of the Academy of Nutrition and Dietetics, Dietitians
of Canada, and the American College of Sports Medicine: Nutrition and Athletic Performance. J. Acad.
Nutr. Diet. 2016, 116, 501–528. [CrossRef] [PubMed]
Aerenhouts, D.; Van Cauwenberg, J.; Poortmans, J.R.; Hauspie, R.; Clarys, P. Influence of growth rate on
nitrogen balance in adolescent sprint athletes. Int. J. Sport Nutr. Exerc. Metab. 2013, 23, 409–417. [CrossRef]
[PubMed]
Juzwiak, C.R.; Ancona-Lopez, F. Evaluation of nutrition knowledge and dietary recommendations by coaches
of adolescent Brazilian athletes. Int. J. Sport Nutr. Exerc. Metab. 2004, 14, 222–235. [CrossRef] [PubMed]
Nichols, J.F.; Rauh, M.J.; Barrack, M.T.; Barkai, H.-S. Bone mineral density in female high school athletes:
Interactions of menstrual function and type of mechanical loading. Bone 2007, 41, 371–377. [CrossRef]
[PubMed]
American Dietetic Association; Dietitians of Canada; American College of Sports Medicine. Nutrition and
athletic performance. Med. Sci. Sports Exerc. 2009, 41, 709–731.
Nielsen, P.; Nachtigall, D. Iron supplementation in athletes. Current recommendations. Sport Med. 1998, 26,
207–216. [CrossRef]
Committee on Nutrition and the Council on Sports Medicine and Fitness. Sports drinks and energy drinks
for children and adolescents: Are they appropriate? Pediatrics 2011, 127, 1182–1189.
Pyne, D.B.; West, N.P.; Cox, A.J.; Cripps, A.W. Probiotics supplementation for athletes-clinical and
physiological effects. Eur. J. Sport Sci. 2015, 15, 63–72. [CrossRef] [PubMed]
Evans, M.J.; Ndetan, H.; Perko, M.; Willimas, R.; Walker, C. Dietary supplement use by children and
adolescents in the United States to enhance sport performance: Results of the National Health Interview
Survey. J. Prim. Prev. 2012, 33, 3–12. [CrossRef] [PubMed]
© 2016 by the authors; licensee MDPI, Basel, Switzerland. This article is an open access
article distributed under the terms and conditions of the Creative Commons Attribution
(CC-BY) license (http://creativecommons.org/licenses/by/4.0/).