Health outcomes associated with vegetarian diets: An umbrella review of systematic reviews and meta-analyses

Oussalah, Abderrahim; Lévy, Julien; Berthezène, Clémence; Alpers, David H.; Guéant, Jean Louis

doi:10.1016/j.clnu.2020.02.037

Cited by 101 publications

(89 citation statements)

References 76 publications

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“…14 Diets similar to the planetary diet such as vegetarian, have an association with reduced risk of adverse health outcomes including diabetes, ischaemic heart disease, and cancer risk, and are projected to confer large healthcare system cost savings in Aotearoa. 15 16 Early developments towards addressing SHDs in Aotearoa have occurred including the creation of an NZ-specific life-cycle assessment (LCA) database, sustainability recommendations from the Ministry of Health to the health sector, assessing attitudes towards SHDs and meat reduction among different sectoral professionals and the public, and optimisation modelling of SHD scenarios. [16][17][18][19][20] We used the DIETCOST programme (a python-based, iterative, multiple solution solver that finds diet outputs that fit various constraints 21 to answer the question: What are the differences in costs and GHG emissions between four dietary patterns in Aotearoa: current (based on national nutrition surveys); healthy (based on dietary guidelines); and flexitarian and vegan (based on the EAT-Lancet planetary diet)?…”

Section: Introductionmentioning

confidence: 99%

Cost and greenhouse gas emissions of current, healthy, flexitarian and vegan diets in Aotearoa (New Zealand)

Kidd

Mackay

Vandevijvere

et al. 2021

BMJNPH

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ObjectiveTo compare the costs and climate impact (greenhouse gas emissions) associated with current and healthy diets and two healthy and environmentally friendly dietary patterns: flexitarian and vegan.DesignModelling studySettingAotearoa (New Zealand).Main outcome measuresThe distribution of the cost and climate impact (kgCO2e/kg of food per fortnight) of 2 weekly current, healthy, vegan and flexitarian household diets was modelled using a list of commonly consumed foods, a set of quantity/serves constraints for each, and constraints for food group and nutrient intakes based on dietary guidelines (Eating and Activity Guidelines for healthy diets and EAT-Lancet reference diet for vegan and flexitarian diets) or nutrition survey data (current diets).ResultsThe iterative creation of 210–237 household dietary intakes for each dietary scenario was achieved using computer software adapted for the purpose (DIETCOST). There were stepwise differences between diet scenarios (p<0.001) with the current diet having the lowest mean cost in New Zealand Dollars (NZ$584 (95% CI NZ$580 to NZ$588)) per fortnight for a family of four) but highest mean climate impact (597 kgCO2e (95% CI 590 to 604 kgCO2e)), followed by the healthy diet (NZ$637 (95% CI NZ$632 to NZ$642), 452 kgCO2e (95% CI 446 to 458 kgCO2e)), the flexitarian diet (NZ$728 (95% CI NZ$723 to NZ$734), 263 kgCO2e (95% CI 261 to 265 kgCO2e)) and the vegan diet, which had the highest mean cost and lowest mean climate impact (NZ$789, (95% CI NZ$784 to NZ$794), 203 kgCO2e (95% CI 201 to 204 kgCO2e)). There was a negative relationship between cost and climate impact across diets and a positive relationship within diets.ConclusionsMoving from current diets towards sustainable healthy diets (SHDs) will reduce climate impact but generally at a higher cost to households. The results reflect trade-offs, with the larger constraints placed on diets, the greater cost and factors such as nutritional adequacy, variety, cost and low-emissions foods being considered. Further monitoring and policies are needed to support population transitions that are country specific from current diets to SHD.

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Section: Introductionmentioning

confidence: 99%

Cost and greenhouse gas emissions of current, healthy, flexitarian and vegan diets in Aotearoa (New Zealand)

Kidd

Mackay

Vandevijvere

et al. 2021

BMJNPH

View full text Add to dashboard Cite

show abstract

“…On the other hand, the higher average score related especially to the physical domain might reflect better health in vegetarians. An umbrella review of meta-analyses published in 2020 showed that vegetarians had a reduced risk of negative health outcomes, such as diabetes, cancer, and ischemic heart disease [ 37 ]. Moreover, vegetarians have lower overweight and obesity rates and better diet quality than nonvegetarians [ 38 , 39 ].…”

Section: Discussionmentioning

confidence: 99%

Quality of Life of Brazilian Vegetarians Measured by the WHOQOL-BREF: Influence of Type of Diet, Motivation and Sociodemographic Data

et al. 2021

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This study aimed to evaluate the general quality of life (QoL) of Brazilian vegetarians. A cross-sectional study was conducted with Brazilian vegetarian adults (18 years old and above). Individuals were recruited to participate in a nationwide online survey that comprised the WHOQOL-BREF as well as sociodemographic and characterization questions related to vegetarianism. The WHOQOL-BREF is composed of 24 items which are divided into four domains (domain 1: physical health; domain 2: psychological well-being; domain 3: social relationships; and domain 4: environment), plus two general items which were analyzed separately, totaling 26 items. The answers from the questionnaire were converted into scores with a 0–100 scale range, with separate analyses for each domain. Results were compared among groups based on the different characteristics of the vegetarian population. A total of 4375 individuals completed the survey. General average score results were 74.67 (domain 1), 66.71 (domain 2), 63.66 (domain 3) and 65.76 (domain 4). Vegans showed better scores when compared to the other vegetarians, except in domain four, where the statistical difference was observed only for semi-vegetarians (lower score). Individuals adopting a vegetarian diet for longer (>1 year) showed better results for domains one and two, with no difference for the other domains. Having close people also adopting a vegetarian diet positively influenced the results for all domains. On the other hand, it was not possible to distinguish any clear influence of the motivation for adopting a vegetarian diet on the scores’ results. Adopting a vegetarian diet does not have detrimental effects on one’s QoL. In fact, the more plant-based the diet, and the longer it was adopted, the better the results were.

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“…The results of our analyses may support the findings of previous studies. An umbrella review from 2020 concluded that vegetarian diets were not associated with a lower risk of stroke mortality [ 25 ]. Previous meta-analyses also demonstrated that vegetarian diets were not linked to cardiovascular and stroke mortality [ 26 , 27 ].…”

Section: Discussionmentioning

confidence: 99%

“…On the contrary, vegetarian diets have been reported to have benefits for multiple health outcomes, such as a lower incidence of type 2 diabetes, coronary heart diseases, obesity, and greater life expectancy [ 26 , 28 , 29 , 30 ]. Besides, vegetarians are proven to have reduced cholesterol levels and cardiovascular diseases [ 25 , 31 , 32 , 33 , 34 , 35 , 36 ].…”

Section: Discussionmentioning

confidence: 99%

Risk of Incident Stroke among Vegetarians Compared to Nonvegetarians: A Systematic Review and Meta-Analysis of Prospective Cohort Studies

et al. 2021

Nutrients

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Vegetarian dietary patterns provide health benefits for cardiovascular health; however, the studies examining the association of vegetarian diets with stroke incidence showed inconsistent findings. We systematically evaluated the risk of incident stroke among vegetarians (diets excluding meat, poultry, fish, and seafood) compared among nonvegetarians. A systematic search of PubMed, EMBASE, Cochrane Library, and Web of Science was performed until 20 May 2021. Prospective cohort studies comparing the risk estimates for incident stroke between vegetarians and nonvegetarians were included. Of 398 articles identified in the database search, data from seven cohort studies (408 total stroke cases in 29,705 vegetarians and 13,026 total stroke cases in 627,728 nonvegetarians) were included. The meta-analysis revealed no significant association between adhering to the vegetarian dietary patterns and the risk of incident stroke (HR = 0.86; 95% CI = 0.67–1.11; I2 = 68%, n = 7). Subgroup analyses suggested that studies conducted in Asia and those with a mean baseline age of participants 50–65 years showed a lower risk of stroke in vegetarians. Moreover, no significant association between vegetarian diets and the risk of ischemic stroke (HR = 0.56; 95% CI = 0.22–1.42; I2 = 82%, n = 3) or hemorrhagic stroke (HR = 0.77; 95% CI = 0.19–3.09; I2 = 85%, n = 2) was found. To be conclusive, no strong relationship between vegetarian diets and the incidence of stroke was observed. Given the limited certainty of evidence from NutriGrade, future well-designed studies are warranted to provide solid evidence on this topic.

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Health outcomes associated with vegetarian diets: An umbrella review of systematic reviews and meta-analyses

Cited by 101 publications

References 76 publications

Cost and greenhouse gas emissions of current, healthy, flexitarian and vegan diets in Aotearoa (New Zealand)

Cost and greenhouse gas emissions of current, healthy, flexitarian and vegan diets in Aotearoa (New Zealand)

Quality of Life of Brazilian Vegetarians Measured by the WHOQOL-BREF: Influence of Type of Diet, Motivation and Sociodemographic Data

Risk of Incident Stroke among Vegetarians Compared to Nonvegetarians: A Systematic Review and Meta-Analysis of Prospective Cohort Studies

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