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Growth and Development of Vegetarian Children

Español - Italiano - from EVU News, Issue 2 /1997 - Româna

The growth and physical fitness of Flemish vegetarian children, adolescents and young adults were recently (1996) studied in the Flemish part of Belgium. The results of this investigation were presented at the Third International Congress on Vegetarian Nutrition, which took place at Loma Linda University, California, March 24-26, 1997.

A résumé of the paper 'Growth, development and physical fitness characteristics of Flemish vegetarian children, adolescents and young adults' authored by Marcel Hebbelinck, Peter Clarys, and Ann De Malsche (Vrije Universiteit Brussel, Laboratories of Human Biometry and of Biological Chemistry) is presented here by the senior author.

In Western Europe today an increasing number of children and young people espouse a vegetarian diet either because they are raised in a vegetarian family or they have decided themselves to become vegetarian.

Concern has been expressed regarding the risks of nutrient deficiency affecting the growth and development of vegetarian children and adolescents, particularly these reared on strict vegetarian (vegan) and macrobiotic diets. Nutritional adequacy of a lacto-ovo-vegetarian diet has been extensively reviewed by Jacobs and Dwyer (1988) and more recently by Sanders and Reddy (1994). Most of the studies under review focused on health aspects of pre-school children, but very few investigated growth, body composition, maturation and physical fitness status of vegetarian school age children and adolescents. For example, in the so-called Farm Study (a vegetarian commune in Tennessee) O’Connell and coll. found that the body height of children up to 10 years of age, raised in a vegetarian commune, was consistently below the US reference values.

In contrast, in two studies in children of Seventh-Day Adventists (SDA) communities, who largely follow a vegetarian lifestyle, no significant differences in height were found, with the exception of SDA school boys who were significantly taller. After controlling for height differences, boys and girls in the SDA school were found to be leaner than their public school peers.

Because of the scarcity of data on physical growth, pubertal development and physical fitness of vegetarian children, adolescents and young adults, we designed a study to assess the average daily dietary intakes of food energy in a total of 82 children (Group A: 6-10 year-old girls and 6-12 year-old boys), adolescents (Group B: 10-16 year-old girls and 12-18 year-old boys), and young adults (Group C: 16-30 year-old-girls and 18-30 year-old boys).

The study included determination of food energy intake (7 days food frequency questionnaire), body height and weight (= size) triceps, suprailiac and calf skinfolds (= fat indicators), puberty characters (pubic hair, breast development and menarche in girls; pubic hair and development of genitalia in boys) (= sexual maturation), hand dynamometry (= grip strength), standing long jump (= leg explosive strength), 30 sec. sit-up (= abdominal dynamic muscular endurance) and a 3 minutes step test (= cardiorespiratory endurance). All results were compared with adequate reference values.

Results
The food energy intake of the vegetarian children, adolescents and young adults were well below the reference values with the greatest differences in the 15 year-old-boys (no.= 4) and girls (no. = 3), the 11 year-old-girls (no. = 3) and the young male adults (no. = 13) attaining 66%, 51%, 71% and 68% of the reference values respectively. In spite of this low energy intake, the vegetarian subjects attained normal height but they were leaner (lower skinfold thickness and body mass indices). It should be pointed out that the recommended energy allowances represent the average needs of individuals and should be regarded as empirically derived estimates applicable for a general population. Furthermore, no allowance is made for individual differences in food energy utilisation, especially in special populations such as vegetarians.

With regard to the physical fitness tests the vegetarian children (Group A) were not different from the population reference values. However, the vegetarian adolescent boys and girls (Group B) and the young adults (Group C) scored on or below the average in standing long jump and 30 sec. sit-up. On the contrary, the vegetarian subjects of Group B (adolescents) and Group C (young adults) performed better in the step test than the reference group. This latter finding suggests that the vegetarian subjects had a better cardiorespiratory endurance capacity. In this respect, it should be noted that a contributing factor may have been the endurance-oriented sports practice of the vegetarian population studied. Moreover, the relative low body mass and the low skinfold fat data may have contributed to the better cardiorespiratory endurance of the vegetarian subjects.

Regarding pubertal development we found that (except for one 12 year-old-girl who was a developer) the adolescent vegetarian boys and girls (Group B) reached sexual maturation stages within the normal range. Moreover, the mean menarcheal age of 13.2 years in the present study corresponds with the most recent figure (1990) of Flemish girls.

In conclusion, the results of the present study support the view that a lacto-(ovo)-vegetarian diet sustains adequate physical growth and development. In comparison to reference values, the vegetarian youngsters are lean, score relatively low in strength tests but high in cardiorespiratory endurance.

Prof. Dr. Marcel Hebbelinck