Our study provides new insights into the sociodemographic and nutritional profiles of self-reported vegetarians and vegans in a large observational study. As expected, self-reported vegetarians and vegans were prone to adopt meat substitution strategies such as higher consumption of plant protein-dense products (e.g., soy-based products or legumes). Vegetarians in our study had the most balanced diet and lower prevalence of dietary nutrient inadequacies.
4.1. Sociodemographic Profiles of Vegetarians and Vegans
Vegetarians in our sample were more likely to be women and individuals with higher educational levels, whereas vegans were more likely to be men and individuals with a lower educational level. Moreover, vegetarians and vegans in our study were more likely to belong to lower income categories, as previously reported in a study conducted in Canada [9
]. This finding may be explained by the fact that educational level has a higher predictive value than other socioeconomic predictors such as occupation or income. This fact has already been reported and discussed in a previous study from the Nutrinet-Santé cohort [47
]. Other previous studies have reported that occupation is related to prestige, skills, and social hierarchy, whereas education can impact skills and knowledge, and thus encourage skills to understand and use all types of nutritional information (guidelines, cooking skills, health promotions messages, etc.) [47
]. Thus, this may explain why income and educational level may be associated in different or opposite ways in our study.
Vegetarians and vegans in our study were both younger than meat-eaters, as previously reported in four studies conducted among adults in the UK, Canada, and the U.S. [6
]. Income and concerns related to food prices may be a motive to follow a vegetarian diet [48
]. In conflict with our findings, it has been reported that vegans were more likely to be manual workers in the UK EPIC-Oxford cohort study [8
]. A previous work conducted in the Nutrinet-Santé study indicated that consumption of animal products was higher for manual workers compared to managerial staff [49
]. Animal food could have a symbolic role (contribution to physical strength and energy), explaining why vegetarian diets may be less popular in this socioeconomic group [49
]. We observed that both vegetarians and vegans were more likely to live alone without children. It has been previously reported that vegans were more likely to be nulliparous, more likely to be single [8
], and that lacto-vegetarians and strict vegetarians (diet comparable to veganism in our study) were more likely to be married [6
]. Indeed, it is possible that individuals switch back to a non-vegetarian diet when they have a child [50
Our findings may also be interpreted in light of sociodemographic determinants of food choice motives such as health, animal welfare, or environment preservation that more deeply established in women [51
], who are thus more prone to adopt a vegetarian diet and to reduce meat consumption [9
]. Moreover, gender representations about meat and masculinity may explain why vegetarianism is more popular among women [52
]. Different cultural settings, populations, and different times of investigations [48
] could also explain our findings. Indeed, previous studies reported that a reduction of meat consumption was not associated with sociodemographic characteristics such as age or education [48
]. It is possible that current growing consumers’ concerns for the protection of the environment may induce dietary changes such the reduction of consumption of animal products [53
]. The reduction of the consumption of animal products may also concern individuals belonging to lower income categories. Also, unlike a previous study that reported a lower proportion of smokers among vegetarians [8
], we did not observe any statistically significant association between smoking status and vegetarianism or veganism in our study sample. It is possible that smoking status is not currently linked with vegetarian diets anymore.
4.2. Compliance with Nutritional Recommendations
The mean contribution of proteins to total energy intake for vegetarians and vegans in our study was similar to those reported in previous studies [6
]. However, while vegetarians had a higher proportion of individuals with protein intake within acceptable range, they also had a greater proportion of individuals under the acceptable intake range for proteins. A previous study also reported that vegetarians had a higher prevalence of protein inadequacy compared to meat- or fish-eaters [19
]. It is recommended to combine proteins from legumes and cereals to reach a higher variety of amino acid intakes [55
]. Compared to meat-eaters, vegetarians and vegans had a higher intake of these food groups as well as a higher intake of soy products. Thus, they may consume a high variety of amino acids, as is recommended [1
]. The mean contribution of saturated fatty acids to total energy intake was higher and that of polyunsaturated fatty acids were lower [6
]. Vegetarians and vegans had a similar proportion of individuals within the acceptable distribution range compared to meat-eaters according to the French nutritional recommendations [56
]. However, vegans had the highest proportion of individuals under the acceptable distribution range of proteins and lipids, suggesting that within this sample, most vegans had an unbalanced macronutrient intake.
In our study, vegetarians and vegans also had a higher intake of PUFAs than meat-eaters. This may be explained by a greater proportion of pesco-vegetarian diets in our study, in addition to a higher intake of plant sources of these fatty acids [1
]. Two studies based on the EPIC-Oxford cohort studies also reported that vegans had the highest intake of PUFAs [8
In our study, the majority of vegans had a fiber intake that met French recommendations [57
]. A smaller portion of vegetarians and only 10% of meat-eaters met the fiber intake recommendation. Most previous studies also reported higher intakes of fiber for vegans and vegetarians, but the gap between meat-eaters and vegans was even larger in our study. Indeed, the fiber intake was 24 to 41% higher in vegans compared to meat-eaters in previous studies [19
], whereas it was about 75% higher in our study.
With regard to micronutrient comparison, vegetarians and vegans had lower intakes of both calcium and vitamin D, in accordance with a previous review [16
], especially for women. Additionally, the bioavailability of calcium from plant sources is an issue, especially for vegans [1
]. Iron inadequacy was lower in vegetarians and vegans compared to meat-eaters, according to French nutritional recommendations for adults. However, it is likely that vegetarians and especially vegans have very low to null intake of heme iron, respectively. Thus, an issue related to food-specific bioavailability of iron, defined as the extent to which dietary iron is absorbed during digestion and used to maintain normal body functions, may remain. Additionally, a previous study [19
] highlighted that iron requirements for vegetarians and vegans may be higher. In fact, a higher consumption of food containing phytates, such as whole grains and legumes [19
], or fibers [58
] may compromise the absorption of iron for people following a vegetarian diet. Nonetheless, vegetarians and vegans had the lowest vitamin C inadequacy, which may improve iron absorption [59
]. Besides, iron deficiency and iron deficiency anemia may not be more common among vegetarians [1
]. Similarly, the bioavailability of zinc for vegetarians has raised questions [60
]. Our results showed that vegans had the highest prevalence of vitamin B12 inadequacy by far. Vitamin B12 deficiency could harm health over a long period (cognitive impairment, stroke, or poor bone health, for example) [1
]. However, all of these potential micronutrient inadequacies, such as vitamin B12, may be balanced by the intake of fortified foods and dietary supplements, as is recommended in some cases for these consumers [1
]. For example, the prevalence of dietary vitamin B12 inadequacy may have been over-estimated among vegetarians and vegans that take dietary supplements.
Taking into account the whole dietary pattern of individuals using the mPNNS-GS, vegetarians better adhered to French dietary guidelines compared to meat-eaters and vegans. This result is in line with a previous study conducted in Belgium that indicated that different types of vegetarians had a higher Healthy Eating Index mean score compared to meat-eaters [22
]. Vegans had a lower mPNNS-GS score, probably due to the computation of the score that allocates points to a moderate consumption of animal products.
Similar to a previous study conducted in the U.S. [25
], the percentage of subjects consuming animal protein substitutes such as soy-based products, cereals, or textured vegetable protein was nearly exclusively consumed by vegetarians and vegans compared to non-vegetarians. The substitution of meat and animal protein by plant-based meat substitutes may contribute to the lower the environmental impact of vegetarian dietary patterns [53
]. Thus, vegetarian diets are more sustainable [54
Some limitations of our study should be acknowledged. First, we used a classification of vegetarianism and veganism based on self-reported food behaviours. A Finnish study [63
] highlighted that self-reported vegetarians and vegans differ from operationalized definitions, based on food consumption, of vegetarianism and veganism. Thus, our results may be specific to self-reported vegetarians and vegans and may not be generalizable to all individuals following a vegetarian or vegan diet. Also, we used self-report classification to define diet groups, whereas previous studies used more categories of vegetarianism (differentiation between fish-eaters, vegetarians, and vegans or strict vegetarians). Thus, vegetarians and vegans had low but not null mean intakes of meat and meat products, as well as other animal protein intakes. Self-reported vegetarians or vegans may in fact consume some meat products, seafood, and dairy products. Our results suggest that the use of self-report appears insufficiently accurate to study the relationship between these diets and health outcomes.
Furthermore, a selection bias is probable, because our sample was based on participants from the NutriNet-Santé study recruited on a voluntary basis with a high proportion of women and participants with a higher educational level. Caution is needed when generalizing the results to the general French population. However, especially for self-reported vegetarians, dietary habits identified in our study may be close to what was reported in previous studies, although other definitions of vegetarianism may have been used, thus improving the external validity of our results.
Comparisons with other studies in terms of nutritional characteristics may be limited by disparities in nutritional recommendations across countries [64
] and by the definition of vegetarian diets. Also, dietary supplement intake was not taken into account in the present study. Further investigations assessing whether the intake of dietary supplements could compensate potential dietary inadequacies are requested. To the best of our knowledge, this is the first study on profiles of vegetarians and vegans conducted in France. Accurate information of dietary consumption and nutritional intakes have been collected and analyzed using a validated method [31
], and taking into account intra-individual variability. Specifically, data were recent and updated and included many “emerging” foods such meat and dairy substitutes.