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Vegetarian children and adolescents’ anthropometric characteristics do not significantly differ from their non-vegetarian counterparts

Pawlak Roman

East Carolina University, Greenville, North Carolina, USA

E-mail : bhuvaneswari.bibleraaj@uhsm.nhs.uk

Ding Qin

East Carolina University, Greenville, North Carolina, USA

Sovyanhadi Marta

California State University, San Bernardino, California, USA

DOI: 10.15761/IFNM.1000178

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Abstract

Approximately 7% of American children and adolescents adhere to vegetarian diets. The few studies that assessed anthropometry among vegetarian children and adolescents were cross sectional, few included vegan children and a handful utilized growth charts. Available data is outdated and is limited to a handful of studies. The goal was to compare anthropometric characteristics of vegetarian with non-vegetarian children and adolescents. We hypothesized that the rate of obesity among vegetarian children and adolescents will be statistically significantly lower than the rate among their non-vegetarian counterparts and that there will be no statistically significant difference in any other anthropometric characteristics among these two groups. CDC’s growth charts were utilized to assess anthropometric data of 218 vegetarians with 308 non-vegetarian children and adolescents. There was no statistically significant difference between the rate of vegetarian vs. non-vegetarian children below the 5th percentile length-for-age (14.1% vs. 10.4% for non-vegetarian girls; Chi square=0.52, df=1, p=0.4708; and 10.2% vs. 4.7%; Chi square=1.84, df=1, p=0.175 for vegetarian vs. non-vegetarian boys). No statistically significant differences were found between the dietary groups in regard to percentages of obese children, defined as BMI-for-age ≥95th percentile, (9.5% vs. 12.7% for vegetarian vs. non-vegetarian girls; Chi-square=0.34, df=1, p=0.5598; and 14% vs. 15.9% for vegetarian vs. non-vegetarian boys; Chi-square=1.03, df=1, p=0.3102). Vegetarian children and adolescents’ anthropometric characteristics do not significantly differ from their non-vegetarian counterparts. 

Key words

vegetarian, obesity, children, anthropometry, growth

Introduction

Vegetarians comprise a diverse group of individuals who adhere to a variety of different diet types. Vegans avoid meat and all foods of animal origin. Lacto-vegetarians do not ingest meat but ingest milk and dairy products, ovo-vegetarians ingest eggs and exclude meat and dairy, while lacto-ovo-vegetarians include milk, dairy and eggs. Pesco-vegetarians ingest fish and/or seafood, while semi-vegetarians eat small amounts of meats. Within the above-described groups are also those who ingest most or all foods as raw foods and those who exclude specific plant products, such as the nightshade vegetables.

Vegetarians are not inclusive to adults. Data from the national poll from 2010 among 1,258, 8 to 18 years old, children and adolescents from the United States showed that 7% of the sample never ate meat [1]. It is generally accepted that vegetarian diets are nutritionally adequate in all stages of life. It has also been assumed that vegetarian diets sustain adequate growth and development among children and adolescents. However, there are surprisingly limited number of research studies that support these assumptions [2-8]. Most of these studies were cross sectional, few of them included vegan children and few utilized growth charts. In addition, the handful of available published studies assessed the growth of vegetarian children from several different countries and among children of different age and ethnic background, making the comparison difficult.

Findings from a number of research papers showed high rates of deficiency of some nutrients, especially vitamin B12 and iron, among vegetarians, especially vegans. Data regarding vitamin B12 status among children and adolescents is very scarce and mainly based on case reports. Vegetarian adults have a very high prevalence of vitamin B12 deficiency [9]. Data on iron status showed an inadequate iron status among children and adolescents that ranged from 4.3%-73% of the studied samples having ferritin below 10 µg/L [10]. These nutrients play a key role in fetal and child growth and development and thus, may impact anthropometric parameters of both children and adolescents.

The goal of the current study was to assess anthropometric differences among children adhering to different dietary patterns. Our hypothesis was that the rate of obesity among vegetarian children and adolescents will be statistically significantly lower than the rate among non-vegetarian children and adolescents and that this will be the only statistically significant difference in the anthropometry of these two groups. The specific objectives included: 1) compare anthropometric data using the Center for Disease Control and Prevention (CDC) growth charts [11], including length-for-age, weight-for-age and BMI-for-age among children and adolescents adhering to different dietary preferences (vegetarian vs. non-vegetarian); 2) to evaluate the percentage of the sample in different percentile categories (e.g. <5th percentile, at and/or above the 95th percentile) among vegetarian and non-vegetarian children; and 3) assess the weight status and obesity prevalence among children in different dietary group using BMI-for-age growth charts, defined as BMI-for-age at or above 95th percentile.

Methods and materials

Data collection

The research protocol was approved by the Institutional Review Board prior to collecting data. Permission from the North American Division of the Seventh-Day Adventist Church to contact its institutions requesting participations was received. Inquiry to different Seventh-Day Adventist Church schools and churches were sent via an e-mail, requesting participation in the research study. Surveys along with letters that explained the goal and the protocol of the study, along with consent forms for parents and assent forms for children were mailed to those institutions that indicated willingness to participate. Surveys were subsequently distributed by school/church officials to parents via students. Participants were asked to complete the survey as a child-parent pair. Completed surveys were either mailed directly to the Principal Investigator (PI) or were returned to schools/churches that subsequently mailed them to the PI. In order to include more vegan children in our study, we placed an announcement about the study on one web-based blog for vegans. Surveys were subsequently collected via e-mails from parents who replied to this advertisement. Students and parents were informed that their participation was completely voluntary. We offered no compensation of any kind to study participants. Data collection took place between the fall of 2011 and late summer 2012.

Survey

The survey consisted of questions related to anthropometric data (e.g. height, weight) of children. Also, we asked questions regarding child’s diet adherence (e.g. lacto-ovo-vegetarian, vegan) and the length of time a child adhered to the selected diet. The dietary options listed in the survey included six categories: 1) all foods including meats such as pork, lobster, and catfish; 2) biblically “clean” meat such as beef and chicken; 3) lacto-ovo-vegetarian diet; 4) lacto-vegetarian diet; 5) ovo-vegetarian diet and 6) only plant foods (vegan).

Statistical analyses

Children’s anthropometry was assessed using the CDC growth charts, using SAS program from the CDC’s website. The gender specific analyses included the following growth charts: BMI-for-age, weight-for-age, and length-for-age. Frequency count and percentages were used to assess the number and the prevalence of children in the following percentile categories: less than 5th percentile, between 5th and less than 10th percentile, between 10th and less than 85th percentile, between 85th and less then 95th percentile, and at and/or above the 95th percentile for each of the three growth charts.

Analyses for vegetarian and non-vegetarian children were performed separately. Due to relatively small number of vegans (n=39), vegan children were included along with other vegetarians in one group called vegetarian group. Chi-square analyses was used to assess whether there were statistically significant differences regarding percentages of vegetarian vs. non-vegetarian children in different percentile categories. A value of <0.05 was used to indicate statistically significant difference.

Results

Demographics

A total of 602 surveys were collected of which 10 were excluded from analyses because a number of questions were left unanswered. An additional 19 surveys were excluded from the growth chart assessments because of missing data regarding age and/or gender. Lastly, we excluded 47 surveys for children younger than 3 years old. Thus, the analyses are based on 526 participants including 237 boys (45.1%) and 289 (54.9%) girls, mean (range) age of 11.4 years (3 to 19). A total of 422 of these children designated membership in the Seventh-Day Adventist Church. Children who adhered to vegetarian diets included 179 lacto- and/or lacto-ovo-vegetarians and 39 vegans. Of those who consumed meat, 304 indicated consuming only meat from animals defined in the Bible as clean animals (e.g. beef, chicken but not pork). Additional data describing participants are included in table 1.

Table 1. Anthropometric characteristics of the sample

 

Vegetarian

Non-vegetarian

Gender

Girls=108

Girls=181

Boys=110

Boys=127

Mean (range) Age

Girls=10.41 (3-20)

Girls=12.09 (3-20)

Boys=10.27 (3-19)

Boys=12.64 (3-18)

Ethnic background

African American=51

African American=102

Asian American=1

Asian American=7

Caucasian=90

Caucasian=29

Hispanic American=36

Hispanic American=93

Mixed=37

Mixed=77

Missing=3

 

Growth charts analysis

Length-for age: The rate of vegetarian girls below the 5th percentile length-for-age reached 14.1% and was higher than the 10.4% for non-vegetarian girls. However, the difference was not statistically significant (Chi square=0.52, df=1, p=0.4708). Similarly, a higher percentage of vegetarian, compared to non-vegetarian, boys were below the 5th percentile length-for-age the difference was not statistically significant (10.2% vs. 4.7%; Chi square=1.84, df=1, p=0.175).

Weight-for-age: There was a statistically significant difference between the rate of vegetarian vs. non-vegetarian girls below the 5th percentile for weight-for-age (13.5% vs. 4.8%; Chi-square=6.46, df=1, p=0.011) but not boys (4.8% vs. 4.7%; Chi-square=0.85, df=1, p=0.3566). The difference between the vegetarian vs. non-vegetarian girls for the weight-for-age at and/or above the 95th percentile was statistically significant (5.8% vs. 15.0%; Chi square=5.36, df=1, p=0.0206). Likewise, there was a statistically significant difference between vegetarian and non-vegetarian boys classified at and/or above the 95th percentile weight-for-age (Chi square=7.04, df=1, p=0.008).

BMI-for-age: The BMI-for-age for the majority of children from both groups was between the 10th and 85th percentile (Table 2). No statistically significant differences were found between the different dietary groups in regard to percentages of obese children (BMI-for-age ≥ 95th percentile). For girls, 9.5% of vegetarian and 12.7% of non-vegetarian (Chi-square=0.34, df=1, p=0.5598) and for boys, 14% of vegetarian and 20.0% of non-vegetarian (Chi-square=1.03, df=1, p=0.3102) were in the obese category. The percentage of girls and boys in the BMI-for age 85th-<95th percentile was 18.9% for vegetarian girls vs. 20.4% of non-vegetarian girls (Chi square=0.01, df=1, p=0.9203) and 15.9% of vegetarian boys and 19.2% of non-vegetarian boys (Chi square=0.22, df=1, p=0.639).

Table 2. Anthropometric findings based on CDC’s growth charts

Percentiles

Total %
(N=526)

Vegetarian Girls
(108)

Non-vegetarian girls
(181)

Vegetarian Boys
(110)

Non-vegetarian boys
(127)

Count (%)

Count (%)

Count %)

Count (%)

Count %)

Length-for-age

N=504

N=99

 N=164

N=108

N=127

     <5th

50 (9.9%)

14 (14.1%)

17 (10.4%)

11 (10.2%)

6 (4.7%)

     5th -<10th

26 (5.2%)

10 (10.1%)

8 (4.9%)

4 (3.7%)

4 (3.1%)

     10th-<85th

303 (60.1%)

54 (54.5%)

94 (57.3%)

62 (57.4%)

89 (70.1%)

     85th-<95th

59 (11.7%)

8 (8.1%)

22 (13.4%)

16 (14.8%)

13 (10.2%)

      95th

66 (13.1%)

13 (13.1%)

23 (14.0%)

15 (13.9%)

15 (11.8%)

Weight-for-age

N=506

N=104

N=167

 N=107

N=123

     <5th

32 (6.3%)

14 (13.5%)

8 (4.8%)

5 (4.7%)

3 (2.4%)

     5th-<10th

7 (1.4%)

0 (0%)

2 (1.2%)

4 (3.7%)

1 (0.8%)

     10th-<85th

311 (61.5%)

70 (67.3%)

102 (61.1%)

69 (64.5%)

67 (54.5%)

     85th-<95th

84 (16.6%)

14 (13.5%)

30 (18.0%)

11 (10.3%)

29 (23.6%)

     ≥95th

72 (14.2%)

6 (5.8%)

25 (15.0%)

18 (16.8%)

23 (18.7%)

BMI-for-age

N=484

N=95

N=157

N=107

N=120

     <5th

26 (5.4%)

10 (10.5%)

4 (2.5%)

10 (9.3%)

3 (2.5%)

     5th- <10th

18 (3.7%)

3 (3.2%)

4 (2.5%)

6 (5.6%)

4 (3.3%)

     10th-<85th

282 (58.3%)

55 (57.9%)

97 (61.8%)

59 (55.1%)

66 (55%)

     85th-<95th

90 (18.6%)

18 (18.9%)

32 (20.4%)

17 (15.9%)

23 (19.2%)

     ≥95th

68 (14.0%)

9 (9.5%)

20 (12.7%)

15 (14.0%)

24 (20.0%)

Discussion

This study compared anthropometric data of vegetarian with non-vegetarian children and adolescents using CDC growth charts. Although not statistically significantly different, compared to non-vegetarian girls and boys, vegetarian girls and boys had lower rate of overweight and obesity, indicative by a lower percentage of children in the at or above 95th and in the 85th to less than 95th percentile, respectively, BMI-for-age (Table 2). These findings are consistent with previous reports that compared vegetarian with non-vegetarian children and/or adolescents. For example, Grant et al. [12] reported 53 vegetarian 14 to 15 years old boys and girls having lower average waist (69.2 vs. 73.5 cm; p<0.01), BMI (20.5 vs. 21.9; p<0.05), and weight (57.8 vs. 62.2 kg; p<0.05), compared to 160 non-vegetarian age-matched peers from New South Wales, Australia.

The obesity rate among children and adolescents participating in this study was lower than the rate based on the National Health and Nutrition Examination Survey (NHANES) study [13]. This was true for male and female vegetarians and for non-vegetarian girls but not for non-vegetarian boys. Overall, 17.0% of the NHANES sample (years 2011-12014) were at or above 95th percentile BMI-for-age compared to 14% in the current study. The percentage of those at or above the 85th percentile among children in the NHANES study (years 2011 – 2012) was almost identical with that in the current study (31.8% vs. 32.6%) (14). Obesity rates among both vegetarian boys and girls was lower in comparison to the NHANES data (9.5% for girls, 14% for boy vs. 17.2% for girls, and 16.7% for boys in NHANES sample in the at and/or above 95th percentile. Likewise, in the current study 28.4% of girls and 29.9% of boys vs. 32.0% of boys and 31.6% of girls in the NHANES sample were in the at and/or above 85th percentile BMI-for-age) [14].

The data from the present study showed mixed results for non-vegetarian girls. Compared to NHANES sample, they had a lower rate of BMI-for-age at or above 95th percentile (12.7%) but a higher rate of BMI-for-age above 85th percentile (33.1%). Non-vegetarian boys from our study, on the other hand, had higher rate of BMI-for-age in both of these categories compared to boys from the NHANES sample (20% at or above 95th percentile and 39.2% above 85th percentile) [14].

With the exception of non-vegetarian boys, our participants had a relatively high rate of length-for-age below 5th percentile (Table 2). Overall, 9.9% of boys and girls (14.1% for vegetarian girls, 10.4% for non-vegetarian girls, 10.2% for vegetarian boys and 4.7% for non-vegetarian boys) were found in this category. This finding is somewhat consistent with data from the Farm Study [2]. In that sample, which was mainly comprised of vegan children, 8% of the sample were found in the length-for-age below 5th percentile. Similarly, our results seem somewhat consistent with findings reported by Hebbelinck et al. [4] In their sample comprised of Flemish vegetarian children, adolescents and young adults, adolescent boys had a mean statue that was 8.5 cm lower than the reference mean. Among participants of that study neither children nor young adults differed from the reference mean in regarding to their height [4].

Limitation

The findings described in this manuscript are largely based on children and adolescent members of the Seventh-Day Adventist Church. Vegetarianism among Seventh-Day Adventists has been promoted since the church’s establishment in the second half of the 19th century. Vegetarian Seventh-Day Adventists have been shown to have lower mortality rate due to cardiovascular disease compared to vegetarians who are not Seventh-Day Adventists [15]. This might mean that diets of Adventist vegetarians are healthier compared to diets of other vegetarians. Thus, the findings may not reflect all vegetarian individuals and communities. This may be especially true of those who become vegetarians for reasons such as weight loss/body image.

Our data is based on a convenience sample of volunteers. Further, we utilized self-reported heights and weights. Thus, the collected data may have had some discrepancies with actual heights and weights. Also, the findings may not be representative of all vegetarian children and adolescents. Although we made an effort to recruit more vegans, the number of vegan children was relatively small (n=39). Thus, separate growth chart analyses were not possible for children in this diet group. Also, it is unclear how data on vegan children and adolescents skewed the findings.

Conclusion and Implications

A smaller percentage of vegetarian compared to non-vegetarian boys and girls were found at and/or above the 95th percentile and at and/or above the 85th to less than the 95th percentile BMI-for-age, even though the differences were not statistically significant. Vegetarians have higher prevalence of being classified in the less than 5th percentile category for BMI-for-age, length-for-age and weight-for-age.

The findings of the current study are somewhat consistent with some previous reports. They show that, by and large, vegetarian children and adolescents’ anthropometric characteristics do not significantly differ from their non-vegetarian counterparts. As stated in the introduction, vegetarians are among groups with high risk of vitamin B12 and iron deficiency. Although deficiencies of these nutrients can impair growth and development, it is unclear to what extent, if at all, they may impact vegetarian children and adolescents’ anthropometry.

Vegetarian lifestyle seems to be on the rise. As many as 7% of American children and adolescents adhere to vegetarian diets [1]. Yet, reliable data based on well-controlled studies, regarding growth and development of vegetarian children and adolescents are lacking. Large, randomized, prospective studies are needed to assess growth and development of vegetarian children and adolescents compared with children on unrestricted diets.

Acknowledgement

We are grateful to all churches and schools for helping us with data collections. The authors have no financial or any other conflict of interest. The research project was no funded. 

References

  1. Stahler C (2016) How Many Youth Are Vegetarian? http://www.vrg.org/press/youth_poll_2010.php.
  2. O'Connell JM, Dibley MJ, Sierra J, Wallace B, Marks JS, et al. (1989) Growth of vegetarian children: The Farm Study. Pediatrics 84: 475-481. [Crossref] 
  3. Leung SS, Lee RH, Sung RY, Luo HY, Kam CW, et al. (2001) Growth and nutrition of Chinese vegetarian children in Hong Kong. J Paediatr Child Health 37: 247-253. [Crossref] 
  4. Hebbelinck M, Clarys P, De Malsche A (1999) Growth, development, and physical fitness of Flemish vegetarian children, adolescents, and young adults. Am J Clin Nutr 70(3 Suppl): 579S-585S.
  5. Nathan I, Hackett AF, Kirby S (1997) A longitudinal study of the growth of matched pairs of vegetarian and omnivorous children, aged 7-11 years, in the north-west of England. Eur J Clin Nutr 51: 20-25. [Crossref] 
  6. Sabaté J, Lindsted KD, Harris RD, Johnston PK (1990) Anthropometric parameters of schoolchildren with different life-styles. Am J Dis Child 144: 1159-1163. [Crossref] 
  7. Sabaté J, Lindsted KD, Harris RD, Sanchez A (1991) Attained height of lacto-ovo vegetarian children and adolescents. Eur J Clin Nutr 45: 51-58. [Crossref] 
  8. Shull MW, Reed RB, Valadian I, Palombo R, Thorne H, et al. (1977) Velocities of growth in vegetarian preschool children. Pediatrics 60: 410-417. [Crossref] 
  9. Pawlak R, Parrott SJ, Raj S, Cullum-Dugan D, Lucus D (2013) How prevalent is vitamin B(12) deficiency among vegetarians? Nutr Rev 71: 110-117. [Crossref] 
  10. Pawlak, Bell (2016) Iron status of vegetarian children. A Review of literature. Submitted for publication to Ann Nutr Metab.
  11. Centers for Disease Control and Prevention, National Center for Health Statistics (2016) Growth charts. https://www.cdc.gov/growthcharts/.
  12. Grant R, Bilgin A, Zeuschner C, Guy T, Pearce R, et al. (2008) The relative impact of a vegetable-rich diet on key markers of health in a cohort of Australian adolescents. Asia Pac J Clin Nutr 17: 107-115. [Crossref] 
  13. Ogden CL, Carroll MD, Lawman HG, Fryar CD, Kruszon-Moran D, et al. (2016) Trends in Obesity Prevalence Among Children and Adolescents in the United States, 1988-1994 Through 2013-2014. JAMA 315: 2292-2299. [Crossref] 
  14. Ogden CL, Carroll MD, Kit BK, Flegal KM (2014) Prevalence of childhood and adult obesity in the United States, 2011-2012. JAMA 311: 806-814. [Crossref] 
  15. Kwok CS, Umar S, Myint PK, Mamas MA, Loke YK (2014) Vegetarian diet, Seventh Day Adventists and risk of cardiovascular mortality: a systematic review and meta-analysis. Int J Cardiol 176: 680-686. [Crossref] 

Editorial Information

Editor-in-Chief

Renee Dufault
Food Ingredient and Health Research Institute

Article Type

Research Article

Publication history

Received date: January 03, 2017
Accepted date: January 21, 2017
Published date: January 25, 2017

Copyright

© 2017 Roman P. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Citation

Roman P (2017) Vegetarian children and adolescents’ anthropometric characteristics do not significantly differ from their non-vegetarian counterparts. Integr Food Nutr Metab 4: DOI: 10.15761/IFNM.1000178.

Corresponding author

Pawlak Roman

Department of Nutrition Science, East Carolina University, Rivers West 337, Greenville, NC 27858, USA

Table 1. Anthropometric characteristics of the sample

 

Vegetarian

Non-vegetarian

Gender

Girls=108

Girls=181

Boys=110

Boys=127

Mean (range) Age

Girls=10.41 (3-20)

Girls=12.09 (3-20)

Boys=10.27 (3-19)

Boys=12.64 (3-18)

Ethnic background

African American=51

African American=102

Asian American=1

Asian American=7

Caucasian=90

Caucasian=29

Hispanic American=36

Hispanic American=93

Mixed=37

Mixed=77

Missing=3

 

Table 2. Anthropometric findings based on CDC’s growth charts

Percentiles

Total %
(N=526)

Vegetarian Girls
(108)

Non-vegetarian girls
(181)

Vegetarian Boys
(110)

Non-vegetarian boys
(127)

Count (%)

Count (%)

Count %)

Count (%)

Count %)

Length-for-age

N=504

N=99

 N=164

N=108

N=127

     <5th

50 (9.9%)

14 (14.1%)

17 (10.4%)

11 (10.2%)

6 (4.7%)

     5th -<10th

26 (5.2%)

10 (10.1%)

8 (4.9%)

4 (3.7%)

4 (3.1%)

     10th-<85th

303 (60.1%)

54 (54.5%)

94 (57.3%)

62 (57.4%)

89 (70.1%)

     85th-<95th

59 (11.7%)

8 (8.1%)

22 (13.4%)

16 (14.8%)

13 (10.2%)

      95th

66 (13.1%)

13 (13.1%)

23 (14.0%)

15 (13.9%)

15 (11.8%)

Weight-for-age

N=506

N=104

N=167

 N=107

N=123

     <5th

32 (6.3%)

14 (13.5%)

8 (4.8%)

5 (4.7%)

3 (2.4%)

     5th-<10th

7 (1.4%)

0 (0%)

2 (1.2%)

4 (3.7%)

1 (0.8%)

     10th-<85th

311 (61.5%)

70 (67.3%)

102 (61.1%)

69 (64.5%)

67 (54.5%)

     85th-<95th

84 (16.6%)

14 (13.5%)

30 (18.0%)

11 (10.3%)

29 (23.6%)

     ≥95th

72 (14.2%)

6 (5.8%)

25 (15.0%)

18 (16.8%)

23 (18.7%)

BMI-for-age

N=484

N=95

N=157

N=107

N=120

     <5th

26 (5.4%)

10 (10.5%)

4 (2.5%)

10 (9.3%)

3 (2.5%)

     5th- <10th

18 (3.7%)

3 (3.2%)

4 (2.5%)

6 (5.6%)

4 (3.3%)

     10th-<85th

282 (58.3%)

55 (57.9%)

97 (61.8%)

59 (55.1%)

66 (55%)

     85th-<95th

90 (18.6%)

18 (18.9%)

32 (20.4%)

17 (15.9%)

23 (19.2%)

     ≥95th

68 (14.0%)

9 (9.5%)

20 (12.7%)

15 (14.0%)

24 (20.0%)