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PEDIATRICS vol. 84 No. 3 September 1 989 475
Growth of Vegetarian Children: The Farm Study
Joan M. OConnell, MHS, Michael J. Dibley, MB BS, Janet Sierra,
RN,Barbara Wallace, PhD, James S. Marks, MD, MPH, andRay Yip, MD,
MPH
From the Division of Nutrition, Center for Health Promotion and
Education, Centers forDisease Control, Atlanta, Georgia, and The
Farm, Summertown, Tennessee
ABSTRACT. To examine the effects of a vegetarian dieton child
growth, height and weight data of 404 vegetarianchildren aged 4
months to 10 years who lived in a collec-tive community in
Tennessee were studied. Height forage, weight for age, and weight
for height were comparedwith the US growth reference. Birth
weights, infant feed-ing patterns, and parental heights were also
evaluated inrelation to growth. Most of the height for age, weight
forage, and weight for height (n = 833) were within the 25thand
75th percentiles of the US growth reference. Themean height for age
and weight for age, however, wereslightly less than the median of
the reference population.For different age groups, the mean height
ranged from0.2 to 2.1 cm and the mean weight ranged from 0.1 to
1.1kg less than the reference median. The largest heightdifference
was observed at 1 to 3 years of age and may bepartly the result of
intrinsic irregularities in the USgrowth reference at those ages.
By 10 years of age, chil-then from The Farm averaged 0.7 cm and 1.1
kg less thanthe reference median, representing only 0.1 and 0.3
SDfrom the reference. Thus, these children have adequateattained
growth, even though it was modestly less thanthat of the reference
population. Pediatrics 1989;84:475-481; vegetarian diet, growth,
height, weight, birth weight.
To examine the effect of a vegetarian diet onchild growth, we
studied height and weight of agroup of infant and vegetarian
children ages 4months to 10 years. The growth ofchildren consum-ing
vegetarian diets was of interest because of thenumber of children
consuming such diets and thespecial dietary needs of children
during periods ofrapid growth. It has been reported that
approxi-mately 4 percent of adults in the United Statesconsume
vegetarian diets. Worldwide, many ethnic
Received for publication Jun 13, 1988; accepted Oct 11,
1988.Reprint requests to (R.Y.) Centers for Disease Control,
Divisionof Nutrition, Mail stop A-41, Atlanta, GA 30333.PEDIATRICS
(ISSN 0031 4005). Copyright 1989 by theAmerican Academy of
Pediatrics.
groups have followed vegetarian diets for centuries.The reasons
people adhere to these diets includereligious, ethical, political,
and health beliefs andeconomic constraints.7
Although several investigators have addressedthe issue of the
growth of vegetarian children, mostof these studies were based on
relatively smallnumbers (50 or fewer) of preschool-aged
child-ren.2#{176} Aside from the small numbers, drawingconclusions
from these studies is somewhat difficultbecause of the variety of
health-related beliefs andlife-styles of the study populations and
the dietarydifferences of the study populations. For example,some
vegetarians have behaviors concerning vita-mm and mineral
supplements and conventionalmedical care that differ from those of
the generalpopulation.82022
The types of vegetarian diets consumed by thestudied populations
must be considered when inter-preting results of the growth
studies. The extent towhich vegetarian diets meet dietary
recommenda-tions varies greatly733 because the term
vegetarianrefers to a broad dietary group of people who avoidmeat
in their diets. It is estimated that 90% of thevegetarians in the
United States are lacto-ovo-vegetarians, who include milk and dairy
productsin their diets. Vegans are vegetarians who avoidall animal
products, including milk and dairy prod-ucts. There exist
additional types of vegetariandiets, some of which involve further
restrictions ondietary intake. Although it may be more difficult
toprovide adequate diets for children with restrictedprotein intake
compared with children who haveno restrictions, all necessary
nutrients, includingvitamins B12 and D, calcium, iron, and zinc,
can beprovided with careful planning.819233
To examine the effect of a vegetarian diet onchild growth, in
this study we describe the growthof vegan children who lived in a
collective commu-nity in Tennessee. In this community, the
children
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476 VEGETARIAN CHILDREN
followed a similar diet and many received vitaminand mineral
supplements. Because growth datawere collected annually, there was
available forstudy a relatively large number of measurements
ofchildren through ten years of age. In addition, weevaluated birth
weights, parental heights, andbreast-feeding patterns in relation
to growth.
SUBJECTS
The children lived in a community called TheFarm, located in
rural central Tennessee. The Farmwas established in 1971 as a
collective communitythat met many of its own needs concerning
healthcare, education, housing, and, to some extent,
foodproduction. The socioeconomic level of the popu-lation of The
Farm was unusual in that the com-munity members were highly
educated, but theygenerated a comparatively small income
fromsources outside the community. The average familyincome was
below the federal poverty level for manyyears but gradually
increased over time. The ma-jority of the children were white and
had lived onThe Farm since birth.
The Farm community was generally well in-formed regarding issues
related to vegetarianism,including complementing different protein
sources,for example, grains and legumes and nonanimalsources of
vitamins and minerals. Until 1983, thepopulation followed a vegan
diet, with soybeansbeing their primary source of protein.
Supplementsof vitamins A, D, and B,2 were added to the soymilk
produced on The Farm. Nutritional yeast(containing vitamin B,2) and
other vitamin andmineral supplements were also used. In the fall
of1983, some members of the community introducedeggs and dairy
products into their diets.
METHODS
1984 Special Growth Survey
In the spring of 1984, we collected height andweight data of 144
children residing on The Farm.We obtained written parental consent
from morethan 95% ofthe families. In addition, a few childrenwere
excluded from the study because of ethnic,dietary, and health
backgrounds that differed fromthe other children raised there or
because they hada chronic illness known to affect their growth.
Body length to the nearest millimeter was deter-mined with a
measuring board for children youngerthan 2 years of age; standing
height was measuredfor older children. We measured their weight to
thenearest 28 g (1 oz) with a Detecto pediatric balancefor children
less than 2 years of age and to thenearest 112 g (quarter pound)
with a beam balance
for children older than 2 years of age. At the sametime, a
subset of the population was measured onseparate days to validate
measurement techniques;no systematic errors were found.
The Farms Annual Growth Surveys
In addition to the data collected in the 1984special growth
survey, we included growth datafrom the annual growth surveys of
The Farm in ouranalyses. Height and weight data from four
cross-sectional surveys performed in the years 1980 to1983 were
included. ETHOS, a Farm research or-ganization, and The Farms
health clinic conductedthe annual surveys because members of The
Farmcommunity were interested in the physical growthof their
children.
The methods used in the 1980 to 1983 growthsurveys were not
subject to the same rigor as the1984 special growth survey. We
evaluated severalcharacteristics of the earlier surveys to
determinethe reliability of those data and to determine
thesuitability of combining the data from The Farmannual surveys
with the data from the 1984 surveyfor cross sectional analyses.
To determine the reliability of the data collectedin each of the
separate cross-sectional surveys, wecompared height for age, weight
for age, and weightfor height data between the 1984 special survey
andthe annual growth surveys of The Farm. No signif-icant
differences were found. Because the surveyswere conducted at the
same time of year, childrenwith multiple measurements in the data
set werenot represented more than once in the age groupbreakdowns
by year. We found no significant dif-ferences in growth, dietary,
or demographic databetween children who had multiple
measurementswith those who had only one measurement andbetween
children measured in 1984 and childrenmeasured in the earlier Farm
surveys. Based onthese analyses, all survey data from 1980 to
1984were combined into one data set.
Dietary, Health, and Demographic Data
To supplement the growth data, we extractedself-reported
information from two health surveysconducted by ETHOS on The Farm
in 1980 and1983. The information included birth date,
dietaryhistory, birth weight, parental height, breast-feed-ing
patterns, vitamins and mineral supplementa-tion, and place of
birth. We also obtained diseasehistories for each child to
determine whether anychildren had disorders of nutritional
significancethat might cause their exclusion from the study.
We evaluated the reliability of the data reportedin the 1980 and
1983 health surveys. If data existed
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TABLE 1. Social, Demographic, and Dietary Data ofThe Farm
Children
Female95th150
I
130
120
* Based on available data.t Mean birth weight 3389 g.:1:Mean
number of months breast-fed was 12 months. Mean age when solid
foods were introduced was 5months.
NCHS
EC.)0.)
Cs
C,)
5th
1 10
100
90
T Mean SD ofI Sample Children
N 380
2 3
ARTICLES 477
for a child from both surveys, the information wascross-checked
for consistency of reporting. No sig-nificant differences were
found in data reported in1980 and 1983. We collected recent dietary
historiesin 1984 to update past survey data.
The dietary data provided in the health surveyswere modified
food frequencies by year and in-cluded the mothers diet during
pregnancy. Weclassified the children as omnivore
(nonvegetarian),lacto-ovovegetarian, or vegan for each year basedon
the amount of eggs, dairy products, and meatsreported in their
diets. We analyzed growth inrelation to the following diet
classifications: themothers diet during pregnancy, the childs
dietfrom birth to age 2 years, and the childs diet during1984. We
were also interested in whether or not thechild had followed a
vegan diet since birth.
For each child, we averaged the heights of themother and father
for a mean parental height.3435We then compared The Farm mean with
the aver-age of the mean heights of 25-year-old men andwomen from a
US reference population.36
Statistical Procedures
We compared weight and height measurementsof the children to the
National Center for HealthStatistics/Centers for Disease Control
growth ref-erence population by age and sex. A growth per-centile
rank was calculated for each set of measure-ments for three growth
indicators: height for age,weight for age, and weight for height.37
We regardeda percentile value greater than the 95th percentileor
less than the 5th percentile as abnormal growth.For each set of
measurements, a standard deviationvalue, Z score, was calculated
for each growth in-dicator based on the growth reference; a Z score
of+1.0 represented 1 SD greater than the mean of thereference
population.tm39 The Z scores were thencompared by age group with
the reference median(presumed mean). We compared the mean Z
scoresof the growth data after stratifying them by meanparental
height, birth weight, sex, and diet. Weused Students t tests and
analysis of covariance todetermine the significance of these
variables inrelation to growth.
RESULTS
We evaluated anthropometric data and healthdata for 404 white
children, who had a total of 833measurements. The mean age at the
time of meas-urement (n = 833) was 71.6 months; 7.7% of thechildren
were less than 2 years of age; 35.7% were2 to 5 years of age, and
56.7% were 6 to 10 years ofage. In Table 1, additional social,
demographic, anddietary information are provided. The mean
birth
Item No.(%)of
Children*
Birth dataBorn on The Farm 304 (82)Lived on The Farm by 2 y of
age 339 (91)Birth wt
-
Female
NCHS
40
at
.c0)a)
50th
T Mean SDof.1_Sample Children
3 4
N 380
5 6 7 8 9 10Age (years)
Fig 3. Weight for age of girls from The Farm relative toNational
Center for Health Statistics (NCHS)/Centersfor Disease Control
percentiles.
Male
NCHS
MaleNCHS
95th
at
Ota)
EC.)a,
.
(I)
40
30
20
50th
25th
5th
T Mean SD ofJ_Sample Children10
80
N 389
678 10
Age (years)Fig 2. Height for age of boys from The Farm relative
toNational Center for Health Statistics (NCHS)/Centersfor Disease
Control percentiles.
478 VEGETARIAN CHILDREN
weight of The Farm children was 3389 g; the per-centage of low
birth weight infants (
-
42#{149}
Female
NCHS
Male
a 26
NCHS
, 95th
at
ata
. 75th
, 50th
, 5th
100 110 110
ARTICLES 479
tically significant at ages 9 and 10 years. Of TheFarm children,
3% were less than the 5th percentileof the weight for age
reference. The Farm weightfor height data were slightly greater
than those ofthe reference population for most ages. The
differ-ences in weight for height were statistically signif-icant
at ages 5 and younger and at age 9 years. OfThe Farm children, 1%
were classified as smallweight for height (weight for height <
5th percent-ile) and 3% as large weight for height (weight
forheight > 95th percentile).
A positive association existed between mean pa-rental height and
the height for age Z scores (P