Comparison between Different Groups of Vegetarianism and Its Associations with Body Composition: A Literature Review from 2015 to 2021

The Relevance of Plant-Based Diets and Micronutrient Supplementation for Body Composition: Data from the VeggieNutri Cross-Sectional Study

OBJECTIVES

This study aimed to compare the anthropometry and body composition of vegetarian and omnivorous adults living in Portugal, while exploring nutritional and health parameters underlying observed differences.

METHODS

425 omnivorous (OMNI), lacto-ovo-vegetarian (LOV), or vegan (VEG) healthy adults were recruited. Anthropometry was measured, and bioelectrical impedance analysis was performed. Participants answered food frequency, sociodemographic, and lifestyle questionnaires. Serum iron, ferritin, and CRP were quantified by spectrophotometry, and serum B12 vitamin and homocysteine were quantified by chemiluminescent microparticle immunoassay.

RESULTS

Total protein intake significantly decreased with increasing strictness of vegetarian habits (median (P25; P75) in g/day: 98.6 (79.5; 123.1), 90.4 (65.9; 121.0), and 87.6 (59.8; 118.5) for OMNI, LOV and VEG, respectively; p = 0.020), and carbohydrate intake was the highest in LOV (median (P25; P75) in g/day: 231.5 (178.4; 287.9), 283.9 (227.3; 342.6), and 263.0 (222.0; 348.3) for OMNI, LOV and VEG, respectively; p = 0.001). VEG were the main users of B12 vitamin (93% in VEG vs. 17% in OMNI and 59% in LOV, p = 0.001), and LOV were the main users of iron supplements (29% in LOV vs. 14% in OMNI and 13% in VEG, p = 0.042), respectively. Blood levels of B12 vitamin correlated negatively with blood homocysteine (rs = -0.386, p < 0.001) and positively with % muscle mass (rs = 0.136, p = 0.005). Participants using iron supplements presented higher C-reactive protein (CRP) (p = 0.014) and they had lower % MM (p = 0.003). Finally, when compared to being OMNI, being LOV independently associated with: (a) having +4.8% (p = 0.002) of fat mass, which could be due to higher carbohydrate intake, and (b) having -2.2% (p = 0.043) of muscle mass. Our data suggest that the association between diet and muscle mass could be attenuated in VEG due to B12 supplementation and/or aggravated in LOV due to iron supplementation-associated inflammation.

The role of vegetarianism, gender, and food choice motivations on vegetable intake among university students

Objective: This study investigated collegians' (N = 466) vegetable consumption as a function of their food choice motivations, gender, and dietary habits. Method: Vegetarians and vegans (veg*ns, n = 94, 60% women), occasional meat eaters (n = 90, 66% women), and omnivores (n = 282, 43% women) completed the Food Choice Questionnaire and reported frequency of vegetable consumption. Results: Veg*ns consumed vegetables more frequently than omnivores and occasional meat eaters. Veg*ns' and occasional meat eaters' food choices were more motivated by natural content, health, and ethics, and less motivated by familiarity compared to omnivores. Women were more motivated than men by weight control. Health concerns predicted vegetable consumption for all dietary groups. Additionally, familiarity predicted veg*ns vegetable consumption, whereas mood, natural content, and convenience predicted omnivores' vegetable consumption. Conclusions: Individual differences in dietary habits and food choice motivations should be considered when designing strategies to promote healthful diets for university students.

Omnivore and vegetarians show similar body composition and skin physiology across body regions-A comparative analysis

BACKGROUND

Skin physiology seems to be influenced by dietary choices and body composition, although links between these factors remain poorly characterised. In the present manuscript, we elaborate on the potential relationships among food groups, body composition and skin physiology in omnivores and vegetarians.

MATERIAL AND METHODS

This cross-sectional observational study involved 181 participants, 129 omnivores and 52 vegetarians. The main functions of the skin measured in our laboratory were transepidermal water loss, deep and superficial epidermal hydration, skin elasticity, and carotenoid content. Skin variables obtained from different body regions were made comparable by a new Proportional Skin Index calculated to respect their relative representativity.

RESULTS

No statistical differences were found when comparing both groups' body composition and skin variables from different body regions, with the exception of the skin carotenoid content significantly higher in the vegetarian group (p < 0.001).

CONCLUSION

Although dietary patterns significantly differed between groups, with vegetarians consuming fewer animal-derived products and more plant-based foods, multiple linear regression analysis revealed no differences or association between the dietary pattern and the skin physiology. These findings highlight the need for further research to elucidate the specific impact of diet and food groups and body composition on skin physiology.

Exploring Vegetarian and Omnivorous Approaches to Cardiovascular Risk and Body Composition

The role of nutrition in preventing non-communicable diseases has been widely studied in recent years, with indications that non-animal-based diets might improve body composition and therefore bring multiple health benefits. For all of these reasons, the main purpose was to compare body composition and metabolic status between vegetarian and omnivorous individuals and relate these values with cardiovascular risk. The present analysis included 176 participants (61 vegetarians and 115 omnivores). Body composition was assessed using a dual-energy X-ray absorptiometry, biochemical parameters obtained from capillary blood, and the 10-year cardiovascular risk (10RCVD) calculated by the QRISK3 score. No statistical differences were found between groups regarding body composition. Concerning metabolic markers, vegetarian individuals showed reduced values of total cholesterol, LDL cholesterol, and non-HDL cholesterol (p < 0.05). There were no differences in 10RCVD between groups. In both diets, moderate correlations between groups were found for cardiovascular risk and visceral adipose tissue. Our results suggest that the vegetarian regimen might be associated with better cardiometabolic biomarkers and better cardiovascular health, although controversial with the body composition trends observed. In conclusion, the results suggest that cardiovascular risk appears to be more influenced by body composition, mainly fat tissue, over dietary patterns itself.

Bone mineral density and body composition in Australians following plant-based diets vs. regular meat diets

Background and aims

Bone mineral density (BMD) and body composition play an important role in maintaining metabolic health and physical functioning. Plant-based diets (PBDs) are known to be lower in protein and calcium, which can impact BMD and body composition. This study aimed to investigate the relationship between various PBDs compared to regular meat diet and whole-body BMD, body composition, and weight status.

Methods

A cross-sectional study was conducted with adults (n = 240) aged 30-75 years, who habitually followed dietary patterns: vegan, lacto-vegetarian, pesco-vegetarian, semi-vegetarian, or regular meat eater (48 per group). Parameters were measured using dual-energy x-ray absorptiometry (DXA), and multivariable regression analyses were used to adjust for lifestyle confounders, socioeconomic factors, and BMI.

Results

After adjustments, whole-body BMD and body composition were not significantly different between those following PBDs and regular meat diets, except for lacto-ovo vegetarians, who had significantly lower lean mass by -1.46 kg (CI: -2.78, -0.13). Moreover, lacto-ovo vegetarians had a significantly lower T-score by -0.41 SD (CI: -0.81, -0.01) compared to regular meat eaters. Waist circumference was significantly lower in individuals adhering to a PBD compared to a regular meat diet: vegans by -4.67 cm (CI: -8.10, -1.24), lacto-ovo vegetarians by -3.92 cm (CI: -6.60, -1.23), pesco-vegetarians by -3.24 cm (CI: -6.09, -0.39), and semi-vegetarians by -5.18 cm (CI: -7.79, -2.57). There were no significant differences in lean mass (%), fat mass (% and total), android/gynoid measures, body weight, or BMI across dietary patterns. All dietary patterns met the recommended dietary intake for calcium and protein, and 25-hydroxy-vitamin D status was comparable across groups.

Conclusions

This cross-sectional study found that adhering to a PBD characterized by varying degrees of dairy and meat restriction is not associated with meaningful changes in BMD or body composition, provided that the dietary patterns are planned appropriately with adequate levels of calcium and protein.

Exploring Vitamin B12 Supplementation in the Vegan Population: A Scoping Review of the Evidence

With a significant portion of the population adopting veganism and conflicting views among nutrition professionals regarding the necessity of vitamin B12 supplementation, this review aims to explore existing studies evaluating interventions through food supplementation. It focuses on the impact of vitamin B12 deficiency across different demographics. The present study seeks to understand how research has addressed the relationship between the rise in veganism and vitamin B12 deficiency over the past decade. A scoping review was conducted following the PRISMA flow diagram. Studies from 2010 to 2023 were identified using Boolean operators and key terms in electronic databases such as PubMed/MEDLINE, Web of Science, and EBSCO (Library, Information Science & Technology Abstracts, and Academic Search Complete). Out of 217 articles identified, 70 studies were included. The topical analysis categorized the studies into three groups: those associating vitamin B12 deficiency with diseases (n = 14), those analyzing the dietary habits of vegetarian individuals (vegan or not) without a specific focus on vitamin B12 (n = 49), and those addressing food guides and nutrition institution positions (n = 7). The authors concluded that vitamin B12 deficiency is prevalent among vegans due to limited consumption of animal products. For vegetarians, supplementation is an efficient means of treating and preventing deficiency; a daily dose of 50 to 100 micrograms is advised. There are still significant gaps in the research, nevertheless, such as the absence of randomized controlled trials evaluating various forms or dosages of vitamin B12 among vegetarians and the requirement for more information and awareness of the vitamin's significance in vegan diets.

Reducing meat and/or dairy consumption in adults: a systematic review and meta-analysis of effects on protein intake, anthropometric values, and body composition

CONTEXT

Consumers are increasingly encouraged to reduce meat and dairy consumption. However, few meta-analyses of randomized controlled trials (RCTs) on the effect of reducing meat and/or dairy on (absolute) protein intake, anthropometric values, and body composition are available.

OBJECTIVE

The aim of this systematic review and meta-analysis was to evaluate the effect of reducing meat and/or dairy consumption on (absolute) protein intake, anthropometric values, and body composition in adults aged ≥ 45 years.

DATA SOURCES

The MEDLINE, Cochrane CENTRAL, Embase, ClinicalTrials.gov, and International Clinical Trials Registry Platform databases were searched up to November 24, 2021.

DATA EXTRACTION

Randomized controlled trials reporting protein intake, anthropometric values, and body composition were included.

DATA ANALYSIS

Data were pooled using random-effects models and expressed as the mean difference (MD) with 95%CI. Heterogeneity was assessed and quantified using Cochran's Q and I2 statistics. In total, 19 RCTs with a median duration of 12 weeks (range, 4-24 weeks) and a total enrollment of 1475 participants were included. Participants who consumed meat- and/or dairy-reduced diets had a significantly lower protein intake than those who consumed control diets (9 RCTs; MD, -14 g/d; 95%CI, -20 to -8; I2 = 81%). Reducing meat and/or dairy consumption had no significant effect on body weight (14 RCTs; MD, -1.2 kg; 95%CI, -3 to 0.7; I2 = 12%), body mass index (13 RCTs; MD, -0.3 kg/m2; 95%CI, -1 to 0.4; I2 = 34%), waist circumference (9 RCTs; MD, -0.5 cm; 95%CI, -2.1 to 1.1; I2 = 26%), amount of body fat (8 RCTs; MD, -1.0 kg; 95%CI, -3.0 to 1.0; I2 = 48%), or lean body mass (9 RCTs; MD, -0.4 kg; 95%CI, -1.5 to 0.7; I2 = 0%).

CONCLUSION

Reduction of meat and/or dairy appears to reduce protein intake. There is no evidence of a significant impact on anthropometric values or body composition. More long-term intervention studies with defined amounts of meat and dairy are needed to investigate the long-term effects on nutrient intakes and health outcomes.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42020207325.

Effects of Different Nutritional Patterns and Physical Activity on Body Composition: A Gender and Age Group Comparative Study

This cross-sectional study analyses differences in dietary habits, taste preferences, variety of protein sources and body composition (BC) profiles among individuals following omnivorous, flexitarian, lacto-ovo-vegetarian and pescatarian diets. Furthermore, it assesses the correlations between these dietary patterns and various sports, classified by exercise intensity, in relation to BC parameters. The study analysed the eating habits and BC data of 1342 participants aged 18-65 years, classified into four diet groups based on their 7-day food diaries and questionnaire responses. Our analysis revealed gender- and age-related differences in weekly food consumption and protein source variety, with men generally consuming more meat, processed meat and fish than women, especially in younger age groups. Differences in dairy and soy consumption were also noted between age groups, while legume and soy preferences showed no gender disparity across all ages. Among non-sporting individuals, vegetarians exhibited lower fat mass (FM%) compared to other diets, while among athletes, vegetarians and pescatarians in in endurance and strength sports, respectively, displayed lower FM%, with flexitarians and omnivores in endurance sports showing higher FM%. Non-athletic omnivores and vegetarians demonstrated a greater proportion of body protein, while among athletes, those engaged in strength training exhibited a higher body protein content across all dietary groups compared to those in endurance training. Among non-athletic groups, vegetarians exhibited the lowest FM/FFM (fat mass/fat-free mass) ratio, while among athletes, vegetarians in endurance sports and participants in strength training across other diets showed lower FM/FFM ratios. The results emphasise the complex interaction between diet, BC and lifestyle choices, revealing how different combinations of diet and sport are associated with optimised BC.

Plant-Based Diets and Metabolic Syndrome Components: The Questions That Still Need to Be Answered-A Narrative Review

Metabolic syndrome (MetS) is defined as the co-occurrence of at least three of the following metabolic disorders: abdominal obesity, hypertriglyceridemia, low high-density lipoprotein cholesterol (HDL-C), high blood glucose, and hypertension. The treatment of MetS involves lifestyle changes, including following an appropriate diet. In addition to weight reduction, it is crucial to search for optimal nutritional patterns that are highly effective in optimizing other MetS markers, such as glucose and lipid metabolism, and reducing blood pressure. To date, the effects of a Mediterranean diet and Dietary Approaches to Stop Hypertension (DASH) diet on MetS have been extensively evaluated. Recent epidemiological studies suggest that plant-based diets (PBDs) may be effective in treating MetS; however, there is still a lack of experimental data. This review aims to analyze the potential benefits of different PBDs on MetS determinants based on the available studies. The findings may help personalize dietary interventions and improve patient care for those with MetS.

Vegetarian diets and diets which restrict animal-source foods during childhood in high-income countries

Increasing numbers of populations in the West are restricting their intake of meat and other animal products for reasons relating to health or ethics; in many countries, these restrictions are already common for cultural, religious, or socio-economic reasons. By following their parent's diet, children are exposed in parallel. This narrative review aims at assessing current data regarding vegetarian diets in children from birth to 18 years of age, which include, by increasing degree of restriction, flexitarian, lacto-ovo-vegetarian, lacto-vegetarian, pescatarian, vegan and macrobiotic diets. The 202 references include 45 studies in children. The more restrictive the diet and the younger the child, the greater the risk of nutritional deficiency. Of particular concern are vitamin B12, iron, zinc, calcium, n-3 long-chain polyunsaturated fatty acids, and protein and energy intake, especially in pregnant and nursing women, infants and young children. Providing an adequate lacto-ovo-vegetarian diet is relatively easy, whereas the maintenance of more restrictive diets may be challenging. The benefits and risks of vegetarian diets in adults are relatively well documented, but data for children are scarce. Vegan and macrobiotic diets should be discouraged in pregnant and lactating mothers as well as in young children, who, otherwise, should pay careful attention to ensuring nutritional adequacy, blood testing and appropriate supplementation. The health consequences of a chosen diet should be discussed with parents and adolescents to ensure the best possible adherence to advice and prescriptions. There is a need for well conducted studies in children but also for better knowledge of nutrition in healthcare professionals.Abbreviations: ALA: α-linolenic acid; ARA: arachidonic acid; ASF: animal source foods; BMC: bone mineral content; BMD: bone mineral density; DHA: docosahexaenoic acid; DRV: dietary reference value; EPA: eicosapentaenoic acid; FLD: flexitarian diet; LA: linoleic acid; LC-PUFA: long-chain polyunsaturated fatty acids; LOVD: lacto-ovo-vegetarian diet; LVD: lacto-vegetarian diet; MAD: macrobiotic diet; OMD: omnivorous diet; PSF: plant-source foods; SFA: saturated fatty acids; VGD: vegetarian diets; VND: vegan diet.

A glimpse of academic staff health behavior on diet type and physical activity at Austrian universities: first findings from the "Sustainably Healthy - From Science 2 Highschool & University" study

Background

The association between lifestyle and health status highlights the importance of assessing health-related behavior in different populations. This multidisciplinary study aimed to examine the health behavior of academic staff of Austrian colleges and universities, with a specific focus on diet types (vegan, vegetarian, omnivorous) and physical activity (PA) reports.

Methods

Following a cross-sectional study design incorporating an online survey, a sample of 1,041 academics from 52 institutes (mean age: 46.4 years) provided data on sociodemographic characteristics, dietary patterns, PA behavior, and other lifestyle behaviors (smoking, alcohol intake, etc.).

Results

The prevalence of vegetarian and vegan diets was 13.2 and 2.0%, respectively, and 33.2% of participants had excess body weight (BMI ≥ 25). The majority of participants (88.5%) reported regularly engaging in leisure-time PA, but 18.6% were active members of sports clubs. No difference between females and males was observed in diet type and the type of sport participation (p > 0.05). Participants with a mixed diet had a higher BMI than vegetarians and vegans (p < 0.05). Leisure-time PA participation was associated with more frequent fruit and vegetable intake (p < 0.05). The prevalence of smoking and alcohol intake was 13.1 and 73.5%, respectively, without any difference between dietary or sports participation subgroups (p > 0.05).

Conclusion

The present study provides an overview of the social trends in vegan and vegetarian diets linked to health behaviors in tertiary educational settings. Findings can be used by health scientists, decision-makers, and multipliers in health and education to improve public health.

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.

The Association between Vegan Dietary Patterns and Physical Activity-A Cross-Sectional Online Survey

A balanced diet and sufficient physical activity (PA) are known to have positive health effects. The relationship between a vegan diet and PA levels is understudied. This cross-sectional online survey aimed to analyze whether different vegan dietary patterns differ in PA. In total, 516 vegan participants were included (June to August 2022). Different dietary patterns were compiled through principal component analysis, while group differences were calculated using independent tests, or chi-squared tests as well as logistic regression analyses. The population had an average age of 28.0 (SD: 7.7) years and had been living vegan for 2.6 (95% CI: 2.5-3.0) years. Two dietary patterns, the "convenience" and the "health-conscious" group, were identified. People with a convenience dietary pattern had significantly higher odds of sitting more (OR 1.10, 95% CI 1.04-1.18) and not achieving aerobic PA (OR 1.81, 95% CI 1.18-2.79) or strength training recommendations (OR 1.81, 95% CI 1.26-2.61) than people with a health-conscious dietary pattern. This study suggests the heterogeneity of vegan diets and that dietary patterns must be differentiated, as they also differ in the level of PA. Additional studies involving complete dietary assessment with a focus on ultraprocessed foods, blood metabolite analysis, and objective PA assessment are required.

Dietary Habits and Lifestyle, Including Cardiovascular Risk among Vegetarians and Omnivores during the COVID-19 Pandemic in the Polish Population

Background: This study assessed how two food groups—omnivores (OMN) and vegetarians (VEGE)—differ in lifestyle changes, including dietary habits during the COVID-19 pandemic. Materials: A total of 861 persons participated in the survey and were divided into two groups: persons following a mixed diet (n = 489) and vegetarians, including vegans (n = 372). The mean age shows no significant differences. Methods: An online survey was conducted on the Polish population during the COVID-19 pandemic. Data was collected using social media; the survey was intended for adults and included separate sheets for different diets (OMN vs. VEGE). Results: The results in both groups were similar regarding the burden of premature diseases. Most respondents (~90%) did not indicate cardiovascular disease abnormalities. In the OMN group, overweight and obesity occurred more often, and the OMN group also showed a higher percentage of people reporting weight gain (OMN 42.7% vs. VEGE 35.9%). The results disclosed the VEGE group significantly more frequently chose products, i.e., vegetables (p = 0.029), legumes (p < 0.001), and dairy products or their plant substitutes (p = 0.002), compared to the OMN group. Conclusions: The VEGE group revealed the most regularities in dietary habits during the pandemic.

Nutritional Status and Habits among People on Vegan, Lacto/Ovo-Vegetarian, Pescatarian and Traditional Diets

Background: This study assessed the possible dependencies between nutritional habits and body composition among subjects with different dietary habits. Materials: A total of 196 healthy (aged 18−50 yrs) participants were enrolled in the study and divided into 4 groups according to their diet: vegans-VEGAN (n = 53), lacto/ovo-vegetarians—VEGE (n = 52), pescatarians-PESCA (n = 28), and omnivores-OMN (n = 43). Methods: The Food Frequency Questionnaire (FFQ) was used, and body composition was assessed on the In-Body120 analyzer. Results: Our result revealed in OMN + PESCA groups a higher average consumption frequency of sweets (p = 0.024), cheese/plant cheese (p < 0.001), eggs and egg dishes/egg substitutes (p < 0.001), butter, margarine/plant margarine (p < 0.001), cream /plant cream (p = 0.018), wine and cocktails (p = 0.028), vodka (p = 0.039) and lower of natural cottage cheese/tofu/tempeh (p < 0.001), vegetable oils (p = 0.036), legumes (p < 0.001) and nuts and seeds(p < 0.001) compared to the VEGAN + VEGE groups. The body composition analysis showed significant differences in skeletal muscle mass (SMM) (p = 0.019) and the content of minerals (p = 0.048) between groups. VEGAN disclosed the lowest average values of body fat mass (BFM), percentage body fat (PBF), and visceral adipose tissue (VAT) than other studied groups. Conclusions: The body composition analysis showed mean values within normal ranges in all of the groups, but some average results of OMN, PESCA, and VEGE compared to VEGAN were not highly satisfactory (in addition to eating behavior outcomes).