Forty-five years of research on vegetarianism and veganism: A systematic and comprehensive literature review of quantitative studies

Rethinking vegetarianism: Differences between vegetarians and non-vegetarians in the endorsement of basic human values

Differences between the basic human values of vegetarians and non-vegetarians were examined in three studies of samples of adults drawn from general populations, one in the US and two in Poland. Vegetarians were oversampled in the US study (514 vegetarians, 540 non-vegetarians) and in one study in Poland (301 vegetarians, 335 non-vegetarians). In the other Polish study, there 68 vegetarians and 1943 non-vegetarians. Values were measured using Schwartz's Portrait Value Questionnaire. Across all three studies, Benevolence, Security, and Conformity values were significantly less important for vegetarians than they were for non-vegetarians, although the difference for Conformity was marginally significant (p < .10) in the US study. Across all three studies, vegetarians also endorsed Tradition values less strongly than non-vegetarians, although this difference was not statistically significant in the US study (p = .12). Across all three studies, vegetarians endorsed Stimulation, Achievement, and Power values more strongly than non-vegetarians did. There was only one value, Self-direction, for which the difference between vegetarians and non-vegetarians varied between the two countries. In the US, Self-direction values were more important for non-vegetarians than they were for vegetarians, whereas in Poland the difference was in the opposite direction. Across the three studies, there were only a few instances in which differences between vegetarians and non-vegetarians varied as a function of respondents' gender. These results suggest that following a vegetarian diet represents a manifestation of values that emphasize independence and individuality, a possibility that is somewhat at odds with how vegetarianism is often discussed.

Assessment of vitamin B12 and homocysteine levels in pregnant women admitted for delivery and cord blood samples of their newborn babies: a multicenter study

BACKGROUND

Vitamin B12, an indispensable micronutrient, is pivotal in numerous physiological processes, with particular significance during pregnancy and fetal development. The increasing adoption of vegetarian diets and the economic challenges associated with accessing animal-based food sources contribute to the prevalence of vitamin B12 deficiency. This study aims to examine the levels of vitamin B12 and homocysteine in pregnant women upon admission for delivery and to analyze corresponding cord blood samples from their newborn infants in a substantial sample within the Istanbul metropolitan area.

MATERIALS AND METHODS

This cross-sectional multicenter study included women aged ≥16 years admitted for delivery and their newborns ≥34 weeks. The demographic data and the results of complete blood counts within the previous 24 hours before birth were recorded. Vitamin B12 and homocysteine levels were measured in maternal and cord blood samples. The study parameters were compared between the groups based on the mothers' and babies' homocysteine and vitamin B12 levels.

RESULTS

The study included 832 pregnant women and 832 neonates. Anemia affected 36% of pregnant women, with a higher frequency in mothers with vitamin B12 deficiency. Seventy-eight mothers and 48.9% of neonates showed Vitamin B12 levels below 200 pg/mL, while elevated homocysteine levels were observed in 30% of mothers and 26% of neonates. Maternal vitamin B12 deficiency was significantly correlated with cord blood B12 deficiency and elevated homocysteine. The median cord blood vitamin B12 level was inversely correlated with the number of previous pregnancies.

CONCLUSION

Vitamin B12 deficiency is extremely common in pregnant women before delivery, significantly correlating to cord blood homocysteine and vitamin B12 levels. However, homocysteine alone is not a reliable marker for maternal vitamin B12 status. Implementing strategies to detect vitamin B12 deficiency and supplying adequate vitamin B12 supplementation during pregnancy holds the potential to enhance maternal and neonatal health in Türkiye.

The association between food neophobia, bi-dimensional aspects of orthorexia, and anxiety among vegetarians and omnivores

Vegetarianism is a growing trend, and food neophobia and orthorexia nervosa could act as barriers to achieving a healthy vegetarian diet. The aim of this study is to compare the levels of food neophobia, anxiety, and both healthy and pathological aspects of orthorexia among vegetarians and omnivores. Additionally, the study aims to identify the relationships between food neophobia, anxiety, and orthorexia. In this cross-sectional online survey, a total of 324 vegetarian and 455 omnivores adults participated. The questionnaire consisted of four sections: sociodemographic, lifestyle, and health-related characteristics, the Food Neophobia Scale (FNS), the Teruel Orthorexia Scale (TOS), and the Generalized Anxiety Disorders-7 Scale. Vegetarians exhibited lower FNS scores (p < 0.001) and had higher healthy orthorexic scores (p < 0.001) than omnivores. There were no differences between groups for anxiety scores (p > 0.05). Regression analysis indicated that higher food neophobia (OR: 0.953, 95% CI:0.937-0.968) and TOS-OrNe scores (OR: 0.946, 95% CI: 0.901-0.993) were associated with lower odds of following a vegetarian diet. Conversely, higher TOS-HeOr scores (OR: 1.135, 95% CI:1.096-1.176) were linked to an increased likelihood of adopting a vegetarian diet. Furthermore, both FNS and GAD-7 scores showed negative correlations with TOS-HeOR (r = -0.124, p < 0.001 and r = -0.129 p < 0.001, respectively), and positive correlations with TOS-OrNe (r = 0.106, p < 0.001 and r = 0.146, p < 0.001). In conclusion, vegetarians exhibit lower levels of food neophobia and a greater interest in healthy eating than omnivores. Additionally, the distinct correlation between two dimensions of orthorexia and food neophobia and anxiety provides support for the two-dimensional nature of orthorexia.

A sustainable and healthy diet: Personality, motives, and sociodemographics

Background

Sustainable and healthy food choices have usually been studied by investigating either consumer choices concerning one product or product group. To investigate dietary patterns are more complex but may be more useful to promote dietary changes among consumers.

Objectives

To identify existing dietary patterns, and to investigate the importance of personality traits, food choice motives, and sociodemographic variables in adopting these patterns.

Methods

A food frequency questionnaire and principal component analysis were used to identify dietary patterns. The importance of food choice motives, sociodemographics, and personality traits were investigated by using ordinary least squares. The personality traits were measured by the Big Five model, and food choice motives were measured by a set of twelve food values.

Results

Three patterns were found and labelled as sustainable, traditional, and unsustainable. The sustainable pattern was positively associated with respondents who were younger, married, females, and having higher income and education. It was also positively associated with openness to experience, conscientiousness, and perceived environmental impact, and it was negatively associated with convenience and price.

Value

The results may be used to target consumer groups for information and marketing activities.

Motivations matter: moral and health-related motives indirectly relate to differential psychological health indicators among vegetarians

Due to rising popularity of vegetarianism in recent years, research interest has surged in examining the relationship between vegetarianism and psychological health. However, given inconsistent findings in prior research, the answer to whether practicing vegetarianism is associated with better or worse psychological health is still elusive. The present investigation aimed to demonstrate that vegetarians are not homogeneous in terms of psychological experiences, such that it is crucial to consider the motives behind vegetarians' dietary choice when examining their psychological health. In a survey study with 266 vegetarians and 104 omnivores, it was shown that health vegetarians displayed higher levels of disordered eating as compared to moral vegetarians and omnivores. Mediation analyses further revealed that, among vegetarians, health motivation was positively correlated with disordered eating tendencies, indirectly linking it with poorer psychological health; moral motivation was positively correlated with prosocial behavior, which in turn predicted better psychological health. These findings have implications for understanding the psychological health of vegetarians with different dietary motives and for developing interventions to promote their psychological health.

Veganism, cuisine, and class: exploring taste as a facilitator in adopting a vegan lifestyle in Santiago, Chile

Introduction

Veganism is a movement that avoids consuming animal products. This lifestyle is commonly represented as elitist despite the broad range of people who follow it. Using Bourdieu's taste theory, this study analyzes how personal culinary tastes of different social classes generate favorable (or unfavorable) dispositions to adopting veganism.

Methods

We analyzed 73 biographical interviews with 40 young vegans in three different waves.

Results

The findings reveal that all social classes exhibit favorable dispositions towards veganism. In upper-class individuals, dispositions to embrace healthy and exotic food facilitate the adoption of new flavors and reflexivity in eating practices. Conversely, lower-class individuals have traditional meatless culinary practices rooted in their restricted budget, facilitating the transition to a plant-based diet.

Discussion

These results demonstrate the relevance of social class in understanding the diversity of vegan practices, and they contribute to breaking stereotypes around this movement.

Nutrient composition of plant-based fast-food meals and their omnivore counterparts: A cross-sectional analysis of e-menus

OBJECTIVES

Fast food chains have introduced many plant-based meals to their menus. We aimed to compare the nutrient composition and allergenic content of plant-based (vegan or vegetarian) meals in fast food chains with their animal-based equivalents.

METHODS

E-menus from 50 fast food chains across 5 countries (Australia, Canada, Poland, the UK, and the US) were analyzed. Data on meal type, weight, calories, macronutrients, sodium, fiber, and allergen presence were gathered. Plant-based meals were matched with meat counterparts, where the latter shared the same meal type, originated from the same country and chain, and showed a weight difference of less than 10%. Multivariate logistic regression analysis was performed.

RESULTS

From n = 2455 records, n = 1868 unique meals were matched. Plant-based meals showed lower odds ratios (OR) for protein (OR, 0.10; 95% confidence interval [CI], 0.08-0.14) and sodium (OR, 0.70; 95% CI, 0.55-0.90) and higher odds for carbohydrates (OR, 1.87; 95% CI, 1.41-2.49), sugar (OR, 1.43; 95% CI, 1.12-1.82), and fiber (OR, 4.87; 95% CI, 3.60-6.63) compared with omnivorous meals, adjusted for country, meal type, and meal weight. Notably, plant-based and omnivorous meals were not associated with total caloric content. Separate analyses of vegetarian and vegan meals yielded similar results. Omnivorous meals more frequently contained allergens such as dairy, eggs, fish, shellfish, and mustard, whereas plant-based meals more likely contained allergens such as sesame, seeds, and nuts.

CONCLUSIONS

Plant-based fast food meals were more likely to contain more carbohydrates, sugar, and fiber and less protein and sodium than their animal-based counterparts. These findings emphasize the importance of informed food choices in the fast food context.

The motivations and practices of vegetarian and vegan Saudis

In the Middle East, particularly in Saudi Arabia, the offering of a meat dish to guests is a deeply embedded cultural tradition, and a meat-based diet is the standard in Saudi Arabia. Thus, the rise of veganism and vegetarianism within Saudi Arabia is surprising and worthy of attention, as is understanding the perceptions and motivations behind this phenomenon, particularly as they relate to food and sustainability. This research was designed to investigate this emerging phenomenon and to identify key differences in dietarian identity between Saudi vegetarians and vegans using Rosenfeld and Burrow's Dietarian Identity Questionnaire. Among other results, the vegan group scored significantly higher on the prosocial motivation construct, suggesting the desire to help society as a whole is a stronger motivating factor for vegans. As well, the vegan cohort scored higher in the personal motivation category. From an environmental and public health perspective, understanding the key factors motivating individuals to adopt a vegetarian or vegan diet in a meat-based culture like Saudi Arabia can be used to encourage others to pursue more healthy and sustainable food behaviors.