EAL

VN: Types and Diversity of Vegetarian Diets (2009)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

To examine consumers’ perceived benefits and barriers to the consumption of a vegetarian diet.

Inclusion Criteria:

Vegetarians specifically recruited for the study.

Exclusion Criteria:

None reported.

Description of Study Protocol:

Recruitment

1,000 people in a southern Australian state were selected at random and mailed questionnaires
Follow-up mailings were sent as reminders and to encourage participation.

Design

A 12-page booklet (200 items) was mailed to each person in the sample along with a cover letter and postage-paid envelope.

Blinding Used

None.

Intervention

None.

Statistical Analysis

The frequency of participants’ responses to the items was measured and cross-tabulations (including Pearson’s chi-squared test of statistical significance) by sex and age group were done. Age groups were formed by splitting respondents’ ages into tertiles: 15 to 39 years; 40 to 55 years; 56 to 91 years.
The results report significance levels of 0.05, 0.01 and 0.001.

Data Collection Summary:

Timing of Measurements

Not reported.

Dependent Variables

Four specific questions (treated as a factor), designed to determine whether the subject believed that meat was unhealthful.

Independent Variables

20 items about beliefs about meat
Perceived benefits of vegetarian diets (24 items)
13 demographic variables were measured including age, sex, occupation, education, marital status, nature of household, income, religion and ethnicity
Self-reported diet group (non-vegetarian, semi-vegetarian and vegetarian).

Description of Actual Data Sample:

Of the 1,000 questionnaires mailed, 70.6% of respondents filled them out
Two questionnaires were unusable, leaving N=601
Approximately 15% (N=146) of the sample could not be contacted.

Attrition (Final N)

Total number of usable questionnaires: 601 (337 women, 256 men in the analyses; eight subjects unaccounted for).

Age

Random survey

15 to 18 years: 0.7%
19 to 24 years: 3.8%
25 to 44 years: 40.9%
45 to 64 years: 33.4%
65 years and older: 21.2%.

Ethnicity

Not reported.

Other Demographics

Random survey

Employed full-time: 29.8%
Employed part-time: 17.6%
Unemployed: 1.7%
Married: 69%
Divorced or widowed: 17.4%.

Anthropometrics

Not reported.

Location

Australia.

Summary of Results:

Of the sample:

1.5% identified as vegetarian
7.2% identified as semi-vegetarian
Approximately half of the semi-vegetarians never or rarely ate red meat
Most (85%) of the vegetarians never ate red or white meat, fish or seafood
Almost 40% of the sample indicated that they were somewhat or very interested in vegetarianism.

Barriers to Being Vegetarian

The table presents the top 10 barriers people indicated to being vegetarian (percentage of respondents who agree with the statement).

Statement	All Respondents	Women	Men	Significant Difference Between Groups	15-39 Years	40-55 Years	56-91 Years	Significant Difference Between Groups
I like eating meat.	78	76	80	NS	80	73	82	NS
I do not want to change my eating habit or routine.	56	57	54	NS	53	52	63	NS
I think humans are meant to eat meat.	44	39	49	0.05	41	33	57	0.001
My family eats meat.	43	44	41	NS	43	32	53	0.001
I need more information about vegetarian diets.	42	42	40	NS	40	42	44	NS
There is too limited a choice when I eat out.	35	34	36	0.001	37	31	37	NS
My friends eat meat.	32	31	32	0.05	31	22	41	0.001
My family/spouse/partner won’t eat vegetarian food.	30	39	18	0.001	35	26	28	NS
I would be (or am) worried about my health (other than lack of iron or protein).	28	31	25	NS	30	21	35	0.001
There is not enough iron in vegetarian diets.	28	29	28	0.01	28	26	30	0.05
It is inconvenient.	23	24	22	0.01	26	17	26	NS

Perceived Benefits of Being Vegetarian

Below are the top 10 benefits respondents identified to being vegetarian (percentage who agree with the statement).

Statement	All Respondents	Women	Men	Significant Difference Between Groups	15-39 Years	40-55 Years	56-91 Years	Significant Difference Between Groups
Eat more fruit and vegetables.	74	75	74	NS	79	71	73	NS
Decrease saturated fat intake in my diet.	65	63	69	0.05	65	67	64	NS
Control my weight.	40	37	42	NS	45	33	41	0.01
Help animal welfare/rights.	36	40	31	0.001	42	37	28	NS
Prevent disease in general (e.g., heart disease, cancer).	36	37	34	NS	40	34	31	0.05
Be healthier by decreasing my intake of chemicals, steroids and antibiotics which are found in meat.	31	36	26	0.01	31	29	35	NS
Stay healthy.	30	32	27	NS	36	22	31	0.001
Eat a greater variety of interesting foods.	25	28	23	NS	24	25	28	0.05
Increase my control over my own health.	23	24	22	NS	27	17	26	0.01
Help the environment.	22	23	21	0.05	29	17	20	0.05

Observations and Implications

The main perceived barrier to adopting a vegetarian diet was enjoying eating meat
Age and cohort differences seemed to be more important than sex differences
The two main perceived benefits were identical for men and women (fruit and vegetables, saturated fat)
Animal welfare benefits ranked eighth among older people, as opposed to third and fourth among middle-aged and younger people, respectively
The youngest group was more likely to agree that there are environmental benefits associated with the consumption of a vegetarian diet (P<0.05), with more than one-fourth in agreement
Apart from health benefits, the results show that animal welfare is related to the apparent interest in vegetarianism, particularly among women. The consumption of more interesting foods and environmental issues were also of some importance.
Older people were in strongest agreement with a relationship between eating a variety of interesting foods and vegetarianism.

Implications

This suggests that the promoters of plant-based diets need to focus on the tastiness and convenience of plant-based meals and perhaps meat analogues.

Author Conclusion:

The main perceived barriers to adopting a vegetarian diet were enjoying eating meat and an unwillingness to alter eating habits. This was the case for men, women and all age groups, although there were sex and age differences present in more than half of the barrier items.
The main benefits associated with vegetarian diets were health benefits: Increased fruit and vegetable intake, decreased saturated fat intake and weight control. Animal welfare-related benefits and disease prevention were also important. Age and sex differences were apparent, although age differences were more important than sex differences.

Funding Source:

University/Hospital:

Deakin University

Reviewer Comments:

The number of vegetarians in the study was very small, so this is unlikely to be representative of vegetarian views
The multiple pair-wise comparisons make findings of P=0.05 questionable.

Quality Criteria Checklist: Primary Research
Relevance Questions
	1.	Would implementing the studied intervention or procedure (if found successful) result in improved outcomes for the patients/clients/population group? (Not Applicable for some epidemiological studies)	N/A
	1.	Would implementing the studied intervention or procedure (if found successful) result in improved outcomes for the patients/clients/population group? (Not Applicable for some epidemiological studies)	N/A
	2.	Did the authors study an outcome (dependent variable) or topic that the patients/clients/population group would care about?	Yes
	2.	Did the authors study an outcome (dependent variable) or topic that the patients/clients/population group would care about?	Yes
	3.	Is the focus of the intervention or procedure (independent variable) or topic of study a common issue of concern to dieteticspractice?	Yes
	3.	Is the focus of the intervention or procedure (independent variable) or topic of study a common issue of concern to dieteticspractice?	Yes
	4.	Is the intervention or procedure feasible? (NA for some epidemiological studies)	N/A
	4.	Is the intervention or procedure feasible? (NA for some epidemiological studies)	N/A

Validity Questions
	1.	Was the research question clearly stated?	Yes
1.	Was the research question clearly stated?		Yes
	1.1.	Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified?	Yes
	1.1.	Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified?	Yes
	1.2.	Was (were) the outcome(s) [dependent variable(s)] clearly indicated?	Yes
	1.2.	Was (were) the outcome(s) [dependent variable(s)] clearly indicated?	Yes
	1.3.	Were the target population and setting specified?	Yes
	1.3.	Were the target population and setting specified?	Yes
	2.	Was the selection of study subjects/patients free from bias?	Yes
2.	Was the selection of study subjects/patients free from bias?		Yes
	2.1.	Were inclusion/exclusion criteria specified (e.g., risk, point in disease progression, diagnostic or prognosis criteria), and with sufficient detail and without omitting criteria critical to the study?	Yes
	2.1.	Were inclusion/exclusion criteria specified (e.g., risk, point in disease progression, diagnostic or prognosis criteria), and with sufficient detail and without omitting criteria critical to the study?	Yes
	2.2.	Were criteria applied equally to all study groups?	Yes
	2.2.	Were criteria applied equally to all study groups?	Yes
	2.3.	Were health, demographics, and other characteristics of subjects described?	Yes
	2.3.	Were health, demographics, and other characteristics of subjects described?	Yes
	2.4.	Were the subjects/patients a representative sample of the relevant population?	Yes
	2.4.	Were the subjects/patients a representative sample of the relevant population?	Yes
	3.	Were study groups comparable?	Yes
3.	Were study groups comparable?		Yes
	3.1.	Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT)	N/A
	3.1.	Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT)	N/A
	3.2.	Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline?	Yes
	3.2.	Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline?	Yes
	3.3.	Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.)	Yes
	3.3.	Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.)	Yes
	3.4.	If cohort study or cross-sectional study, were groups comparable on important confounding factors and/or were preexisting differences accounted for by using appropriate adjustments in statistical analysis?	Yes
	3.4.	If cohort study or cross-sectional study, were groups comparable on important confounding factors and/or were preexisting differences accounted for by using appropriate adjustments in statistical analysis?	Yes
	3.5.	If case control study, were potential confounding factors comparable for cases and controls? (If case series or trial with subjects serving as own control, this criterion is not applicable.)	Yes
	3.5.	If case control study, were potential confounding factors comparable for cases and controls? (If case series or trial with subjects serving as own control, this criterion is not applicable.)	Yes
	3.6.	If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")?	N/A
	3.6.	If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")?	N/A
	4.	Was method of handling withdrawals described?	Yes
4.	Was method of handling withdrawals described?		Yes
	4.1.	Were follow-up methods described and the same for all groups?	N/A
	4.1.	Were follow-up methods described and the same for all groups?	N/A
	4.2.	Was the number, characteristics of withdrawals (i.e., dropouts, lost to follow up, attrition rate) and/or response rate (cross-sectional studies) described for each group? (Follow up goal for a strong study is 80%.)	Yes
	4.2.	Was the number, characteristics of withdrawals (i.e., dropouts, lost to follow up, attrition rate) and/or response rate (cross-sectional studies) described for each group? (Follow up goal for a strong study is 80%.)	Yes
	4.3.	Were all enrolled subjects/patients (in the original sample) accounted for?	No
	4.3.	Were all enrolled subjects/patients (in the original sample) accounted for?	No
	4.4.	Were reasons for withdrawals similar across groups?	N/A
	4.4.	Were reasons for withdrawals similar across groups?	N/A
	4.5.	If diagnostic test, was decision to perform reference test not dependent on results of test under study?	N/A
	4.5.	If diagnostic test, was decision to perform reference test not dependent on results of test under study?	N/A
	5.	Was blinding used to prevent introduction of bias?	Yes
5.	Was blinding used to prevent introduction of bias?		Yes
	5.1.	In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate?	N/A
	5.1.	In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate?	N/A
	5.2.	Were data collectors blinded for outcomes assessment? (If outcome is measured using an objective test, such as a lab value, this criterion is assumed to be met.)	Yes
	5.2.	Were data collectors blinded for outcomes assessment? (If outcome is measured using an objective test, such as a lab value, this criterion is assumed to be met.)	Yes
	5.3.	In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded?	Yes
	5.3.	In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded?	Yes
	5.4.	In case control study, was case definition explicit and case ascertainment not influenced by exposure status?	N/A
	5.4.	In case control study, was case definition explicit and case ascertainment not influenced by exposure status?	N/A
	5.5.	In diagnostic study, were test results blinded to patient history and other test results?	N/A
	5.5.	In diagnostic study, were test results blinded to patient history and other test results?	N/A
	6.	Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described?	Yes
6.	Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described?		Yes
	6.1.	In RCT or other intervention trial, were protocols described for all regimens studied?	N/A
	6.1.	In RCT or other intervention trial, were protocols described for all regimens studied?	N/A
	6.2.	In observational study, were interventions, study settings, and clinicians/provider described?	Yes
	6.2.	In observational study, were interventions, study settings, and clinicians/provider described?	Yes
	6.3.	Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect?	Yes
	6.3.	Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect?	Yes
	6.4.	Was the amount of exposure and, if relevant, subject/patient compliance measured?	N/A
	6.4.	Was the amount of exposure and, if relevant, subject/patient compliance measured?	N/A
	6.5.	Were co-interventions (e.g., ancillary treatments, other therapies) described?	N/A
	6.5.	Were co-interventions (e.g., ancillary treatments, other therapies) described?	N/A
	6.6.	Were extra or unplanned treatments described?	N/A
	6.6.	Were extra or unplanned treatments described?	N/A
	6.7.	Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups?	N/A
	6.7.	Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups?	N/A
	6.8.	In diagnostic study, were details of test administration and replication sufficient?	N/A
	6.8.	In diagnostic study, were details of test administration and replication sufficient?	N/A
	7.	Were outcomes clearly defined and the measurements valid and reliable?	Yes
7.	Were outcomes clearly defined and the measurements valid and reliable?		Yes
	7.1.	Were primary and secondary endpoints described and relevant to the question?	Yes
	7.1.	Were primary and secondary endpoints described and relevant to the question?	Yes
	7.2.	Were nutrition measures appropriate to question and outcomes of concern?	Yes
	7.2.	Were nutrition measures appropriate to question and outcomes of concern?	Yes
	7.3.	Was the period of follow-up long enough for important outcome(s) to occur?	N/A
	7.3.	Was the period of follow-up long enough for important outcome(s) to occur?	N/A
	7.4.	Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures?	Yes
	7.4.	Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures?	Yes
	7.5.	Was the measurement of effect at an appropriate level of precision?	Yes
	7.5.	Was the measurement of effect at an appropriate level of precision?	Yes
	7.6.	Were other factors accounted for (measured) that could affect outcomes?	Yes
	7.6.	Were other factors accounted for (measured) that could affect outcomes?	Yes
	7.7.	Were the measurements conducted consistently across groups?	Yes
	7.7.	Were the measurements conducted consistently across groups?	Yes
	8.	Was the statistical analysis appropriate for the study design and type of outcome indicators?	Yes
8.	Was the statistical analysis appropriate for the study design and type of outcome indicators?		Yes
	8.1.	Were statistical analyses adequately described and the results reported appropriately?	Yes
	8.1.	Were statistical analyses adequately described and the results reported appropriately?	Yes
	8.2.	Were correct statistical tests used and assumptions of test not violated?	No
	8.2.	Were correct statistical tests used and assumptions of test not violated?	No
	8.3.	Were statistics reported with levels of significance and/or confidence intervals?	Yes
	8.3.	Were statistics reported with levels of significance and/or confidence intervals?	Yes
	8.4.	Was "intent to treat" analysis of outcomes done (and as appropriate, was there an analysis of outcomes for those maximally exposed or a dose-response analysis)?	N/A
	8.4.	Was "intent to treat" analysis of outcomes done (and as appropriate, was there an analysis of outcomes for those maximally exposed or a dose-response analysis)?	N/A
	8.5.	Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)?	Yes
	8.5.	Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)?	Yes
	8.6.	Was clinical significance as well as statistical significance reported?	Yes
	8.6.	Was clinical significance as well as statistical significance reported?	Yes
	8.7.	If negative findings, was a power calculation reported to address type 2 error?	N/A
	8.7.	If negative findings, was a power calculation reported to address type 2 error?	N/A
	9.	Are conclusions supported by results with biases and limitations taken into consideration?	Yes
9.	Are conclusions supported by results with biases and limitations taken into consideration?		Yes
	9.1.	Is there a discussion of findings?	Yes
	9.1.	Is there a discussion of findings?	Yes
	9.2.	Are biases and study limitations identified and discussed?	Yes
	9.2.	Are biases and study limitations identified and discussed?	Yes
	10.	Is bias due to study's funding or sponsorship unlikely?	Yes
10.	Is bias due to study's funding or sponsorship unlikely?		Yes
	10.1.	Were sources of funding and investigators' affiliations described?	No
	10.1.	Were sources of funding and investigators' affiliations described?	No
	10.2.	Was the study free from apparent conflict of interest?	Yes
	10.2.	Was the study free from apparent conflict of interest?	Yes