The role of intestinal Prevotella species in human health is controversial, with both positive and negative associations. Strain-level diversity may contribute to discrepancies in genus and species ...associations with health and disease. We dissected the gut metagenomes of Italians with varying dietary habits, investigating the presence of distinct Prevotella copri strains. Fiber-rich diets were linked to P. copri types with enhanced potential for carbohydrate catabolism. P. copri strains associated with an omnivore diet had a higher prevalence of the leuB gene—involved in branched-chain amino acid biosynthesis—a risk factor for glucose intolerance and type 2 diabetes. These P. copri pangenomes were compared to existing cohorts, providing evidence of distinct gene repertoires characterizing different P. copri populations, with drug metabolism and complex carbohydrate degradation significantly associated with Western and non-Western individuals, respectively. Strain-level P. copri diversity in gut microbiomes is affected by diet and should be considered when examining host-microbe associations.
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•Screening of human gut metagenomes reveals different Prevotella copri pangenomes•Habitual diet and lifestyle can select different P. copri strains•Strains from non-Western subjects show higher potential for complex fiber break-down•Strains from Western subjects have a higher prevalence of drug metabolism genes
The gut microbiome includes several strains per species, with high genomic diversity. By examining Italian subjects with varying dietary habits, De Filippis et al. demonstrate that diet may select distinctive Prevotella copri strains with distinguishable functions. This diversity may explain subject-specific responses to dietary interventions and variations in human health.
Health effects of vegan diets among children and adolescents are a controversial public health topic. Thus, the aim of the present systematic review is to evaluate a broad range of health outcomes ...among vegan children and adolescents aged 0 to 18 years. 18 studies met the inclusion criteria (17 cross-sectional, 1 RCT). Meta-analyses showed lower protein, calcium, vitamin B2, saturated fatty acid, and cholesterol intakes, and lower ferritin, HDL and LDL levels as well as height in vegan compared to omnivorous children/adolescents. Higher intakes of carbohydrates, polyunsaturated fatty acids, fiber, folate, vitamins C and E, magnesium, iron, and potassium were observed in vegans. Blood levels of vitamin B12 were higher among vegan children due to supplement use. Single study results suggested further differences between vegan and non-vegan children, such as lower bone mineral content or urinary iodine among vegan children. Risk of Bias was rated as high or very high in 7 out of 18 studies. The certainty of evidence for the meta-analyses was low (n = 2) or very low (n = 46). Overall, the available evidence points to both risks and benefits associated with a vegan diet among children, although more and better designed studies are needed.
Vegan diets have risen in popularity over the past 9 years. However, few studies have examined nutrient status and the effect of a vegan diet on the growth of children. This study analysed the ...existing literature on the health impact and growth impact of selected nutrients in vegan children. We assessed the intake of calories and protein, as well as the nutrients iron, calcium, vitamin D, cobalamin and folate. With a small percentage of outliers, vegan children showed normal growth and were less often obese. We found limited evidence that children on a vegan diet can obtain all the examined nutrients. Furthermore, as proper planning and supplementation by caregivers is needed, it is currently unknown how often vegan children follow well-planned diets. Deficiencies in cobalamin, calcium, and vitamin D seem to be the biggest risks associated with a poorly planned vegan diet. For a more definitive assessment, data on the intake and nutrient status of omega-3 fatty acids, zinc, iodine, and selenium in vegan children are needed. Future research should account for demographic shifts in those following a vegan diet, and should discriminate between vegan sub-populations that are open or closed towards scientific approaches, towards health in general, and toward supplementation. Studies should assess the modes and dosages of supplementation and the use of fortified foods or drinks, as well as adherence to the diet itself. Plant ferritin as a source of iron and endogenous cobalamin synthesis warrants further scientific inquiry. In summary, the current literature suggests that a well-planned vegan diet using supplementation is likely to provide the recommended amounts of critical nutrients to provide for normal progression of height and weight in children, and can be beneficial in some aspects. However, data on 5 critical nutrients are still missing, hampering a more definitive conclusion.
Reducing meat consumption is highly effective for reducing personal carbon emissions, yet most people in Western nations still eat meat. We build on recent research highlighting that group boundaries ...may impede dietary change by (a) promoting pro-meat norms and (b) prohibiting critical calls for a veg* diet (vegetarian and vegan, i.e., meat-free). Past research relied on self-reports and behavioural measures of engagement, leaving open whether these effects extend to food consumption settings and ad-hoc meal choice. We conducted two pre-registered experiments in which meat-eaters read critical calls to adopt a veg* diet, either by a vegan (outgroup) or a meat-eater (ingroup). In Experiment 2, participants moreover read an article either highlighting a veg* or a meat-eating norm. We then assessed actual (Experiment 1) or hypothetical (Experiment 2) meal choice as dependent variables. As predicted, intergroup criticism (i.e., voiced by veg*s) consistently led to message rejection in comparison to the same criticism voiced by meat eaters, but we did not observe effects on meal choice. Norms neither had a main nor interaction effect on self-reports and behaviour. We discuss potential intermediary processes between engagement with and adoption of a vegan diet and derive evidence-based recommendations for constructive communication across group boundaries.
Interest in vegetarian diets is growing in Italy and elsewhere, as government agencies and health/nutrition organizations are emphasizing that regular consumption of plant foods may provide health ...benefits and help prevent certain diseases.
We conducted a Pubmed search, up to September, 2015, for studies on key nutrients (proteins, vitamin B12, iron, zinc, calcium, vitamin D, and n-3 fatty acids) in vegetarian diets. From 295 eligible publications the following emerged: Vegetarians should be encouraged to supplement their diets with a reliable source of vitamin B12 (vitamin-fortified foods or supplements). Since the plant protein digestibility is lower than that of animal proteins it may be appropriate for vegetarians to consume more proteins than recommended for the general population. Vegetarians should also be encouraged to habitually consume good sources of calcium, iron and zinc – particularly vegetables that are low in oxalate and phytate (e.g. Brassicaceae), nuts and seeds, and calcium-rich mineral water. Calcium, iron, and zinc bioavailability can be improved by soaking, germination, and sour-dough leavening that lower the phytate content of pulses and cereals. Vegetarians can ensure good n-3 fatty acid status by habitually consuming good sources of a-linolenic acid (walnuts, flaxseeds, chia seeds, and their oils) and limiting linoleic acid intake (corn and sunflower oils).
Well-planned vegetarian diets that include a wide variety of plant foods, and a reliable source of vitamin B12, provide adequate nutrient intake. Government agencies and health/nutrition organizations should provide more educational resources to help Italians consume nutritionally adequate vegetarian diets.
•Vegetarian diets that include a wide variety of plant foods provide adequate nutrient intake for Italians of all ages.•However, vitamin B12 intake may be low, so vitamin-fortified foods/B12 supplements are advised.•Vegetarians should eat more protein than recommended for omnivores because of reduced plant protein digestibility.•Vegetarians should eat good sources of Ca, Fe and Zn and prepare foods to enhance Ca, Fe and Zn bioavailability.•Vegetarians should eat sufficient α-linolenic acid and limit linoleic acid intake.
While animal products are rich in protein, the adequacy of dietary protein intake from vegetarian/vegan diets has long been controversial. In this review, we examine the protein and amino acid ...intakes from vegetarian diets followed by adults in western countries and gather information in terms of adequacy for protein and amino acids requirements, using indirect and direct data to estimate nutritional status. We point out that protein-rich foods, such as traditional legumes, nuts and seeds, are sufficient to achieve full protein adequacy in adults consuming vegetarian/vegan diets, while the question of any amino acid deficiency has been substantially overstated. Our review addresses the adequacy in changes to protein patterns in people newly transitioning to vegetarian diets. We also specifically address this in older adults, where the issues linked to the protein adequacy of vegetarian diets are more complex. This contrasts with the situation in children where there are no specific concerns regarding protein adequacy because of their very high energy requirements compared to those of protein. Given the growing shifts in recommendations from nutrition health professionals for people to transition to more plant-based, whole-food diets, additional scientific evidence-based communications confirming the protein adequacy of vegetarian and vegan diets is warranted.
The number of consumers following a vegan diet has notably increased in many industrialised countries and it is likely that their influence on the food sector will continue to grow. The aim of the ...present study was to identify different segments of consumers according to their motivation for following a vegan diet. Another objective was to analyse the attitudes of these consumers towards animal agriculture. The main focus was to determine whether all consumers following a vegan diet oppose animal agriculture in general or if some of these consumers accept certain forms of animal agriculture. The 2014 study, conducted at seven vegan supermarkets in Germany, was based on face-to-face interviews with 329 consumers following a vegan diet. The open question on consumer motivations for adopting a vegan diet revealed three main motives: Animal-related motives (mentioned by 89.7% of the respondents), motives related to personal well-being and/or health (69.3%), and environment-related motives (46.8%). The two-step cluster analysis identified five consumer segments with different motivations for following a vegan diet. The vast majority of respondents (81.8%) mentioned more than one motive. We conclude that making a dichotomous segmentation into ethical versus self-oriented consumers, as previous authors have done, disregards the fact that many consumers following a vegan diet are driven by more than one motive. The consumer segments had significantly different attitudes towards animal agriculture. We identified consumers following a vegan diet (about one third of the sample) who might be open to forms of animal agriculture guaranteeing animal welfare standards going beyond current practices. The present study has interesting implications for the food sector and the agricultural sector.
In light of the considerable pressure exerted by food production on the environment, the assessment of the environmental burdens of dietary choices has recently gained interest among the scientific ...community. Several studies based on life cycle thinking approach agreed that a transition from an omnivorous to either a vegan or vegetarian diets would reduce the environmental impact associated with food consumption. The majority of the studies set the system boundaries up to the retail, excluding the consumption phase and generally do not account for uncertainties. The aim of the present study was to assess how personal consumption choices and behaviour can affect the greenhouse gas emissions generated by three balanced dietary patterns (omnivorous, vegetarian and vegan), defined on the basis of nutritional recommendations for an average Italian man. It took into consideration the uncertainties associated with three elements, namely the greenhouse gas emissions due to the production of the food items, the emissions associated with cooking and the food wasted by consumers.
The results of the study highlighted that, despite the higher share of greenhouse gas emissions of the supply chain stages prior to consumption (66%–74% of the total emissions), domestic behaviours have an important influence of the total greenhouse gas emissions of the diet, which can offset the lower GHG emissions due to the choice of vegetable-origin foods. In fact, 15%–21% of the total emissions are associated to the cooking phase and 11%–13% to the food waste generation. Therefore, this study remarks the importance of adopting a cradle to grave perspective when assessing the environmental burden of dietary patterns and emphasises the central role of consumers in the definition of low GHG-emitting dietary patterns.
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•Cradle to grave approach should be preferred comparing dietary patterns.•Production of food has to be considered within consumption and food waste stages.•Omnivorous, vegetarian and vegan diets have different impact on climate.•Consumers have a central role in the definition of low GHG-emitting dietary patterns.•Further modelling efforts needed to improve the modelling of personal behaviour.
Abstract
Background
The vast majority of the world population declares affiliation to a religion, predominantly Christianity and Islam. Many religions have special dietary rules, which may be more or ...less strictly adhered to.
Methods
Religious food rules were collected from holy books and religious websites as well as their translation into dietary practices. The literature was searched for potential associations between these rules and potential nutritional consequences.
Results
Jewish, Islamic and Indian religions support prolonged breastfeeding. Religious avoidance of alcohol is probably beneficial to health. When strictly applied, a few rules may lead to nutritional inadequacies, mainly in populations living in unfavourable socio-economic or environmental conditions. In Jewish and Muslim observants, animal slaughtering procedures may increase the risk of iron deficiency. Jews may be at risk of excess sodium intake related to home-prepared foods. A vegan diet, as observed by some believers, often by drifting from original precepts, or by some Hindus or Buddhists, may result in vitamin B12, calcium, iron, zinc, selenium and n-3 fatty acids deficiencies.
Conclusion
When implemented in accordance with the rules, most religious food precepts are not detrimental to health, as suggested by the fact that they have more or less been followed for millennia. Nevertheless, some practices may lead to nutritional inadequacies, such as iron, calcium, vitamin D and vitamin B12 deficiencies. Patients with low socio-economic status, children and women of childbearing age are of particular risk of such deficiencies. Being aware of them should help health professionals to take an individualized approach to decide whether to supplement or not.