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Reactions: study identifies genes that may be associated with vegetarianism

A US research team has identified several genes that may be associated with a strict vegetarian diet. Some of these genes have "important roles in lipid metabolism and brain function", according to the paper, which suggests that these differences could explain the ability to subsist on a vegetarian diet in those who carry these genes. The study, published in the journal PLoS ONE, used data from the UK Biobank to compare a group of more than 5,000 vegetarians with a group of more than 320,000 non-vegetarians.

04/10/2023 - 20:00 CEST
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José M. Ordovás - vegetarianos genes EN

José M. Ordovás

Director of Nutrition and Genomics at Tufts University in Boston (USA), member of IMDEA-Alimentación (Madrid) and CIBEROBN (Carlos III Health Institute)

Science Media Centre Spain

The study used data from the UK Biobank, which included dietary and genetic information from a very large sample of more than 500,000 individuals. It also used a genome-wide association study (GWAS) to identify loci [fixed position on a chromosome, which determines the position of a gene] associated with strict vegetarianism. The use of a reputable data source such as the UK Biobank and a comprehensive method such as GWAS implies a robust research design.  

The conclusions drawn - that there may be genetic factors influencing vegetarianism, especially those related to lipid metabolism and genes expressed in the brain - appear to be supported by the identification of the SNP, also called a single nucleotide SNP, on chromosome 18 and the subsequent genetic associations.  

The article mentions that previous studies have linked the identified genes to neurological disorders, cognitive performance and alcohol consumption. We have also conducted similar studies related to coffee and dairy consumption. Taken together, this and previous studies provide evidence pointing to the heritability of dietary preferences, in this specific case, vegetarianism. The uniqueness of the work appears to lie in its in-depth focus on the genetic factors underlying vegetarianism using a large dataset from the UK Biobank.  
There are limitations:  

  • The study is based on self-reported dietary data. Self-reporting can often introduce bias, as participants may not recall information accurately or provide socially desirable responses.  
  • There is a lack of diversity in the study population, which may affect the generalisability of the results. Without more information on this limitation, it could be assumed that the results are mainly representative of the UK population, healthy and upper class, and may not extend to other ethnic or cultural groups. 
  • Another important limitation is not knowing the reasons for the adoption of vegetarianism, which may be multiple and have biological, psychological, cultural, environmental, religious, etc. roots. Such information would have been essential to differentiate genes that are more related to lipid metabolism or those that are expressed in the brain.   

Understanding the genetic factors that influence dietary choices such as vegetarianism may have practical implications:  

  • Personalised dietary recommendations: knowing one's genetic predispositions could allow for better tailored dietary recommendations, which could lead to better health outcomes. 
  • Clinical implications: as some of the genes are linked to neurological disorders and cognitive performance, further research could lead to a deeper understanding of how diet and metabolism influence these conditions.  
  • Possible interventions: if certain genetic factors predispose people to a vegetarian diet or vice versa, interventions can be designed to help those who may face health problems due to their dietary preferences.  

In summary, this study appears to be of good quality and provides interesting information on genetic factors influencing vegetarianism, although with some limitations. The findings may be of importance in everyday life as well as in clinical practice.

The author has declared they have no conflicts of interest

Marta Ribasés - vegetarianismo genes EN

Marta Ribasés Haro

Head of the Psychiatric Genetics Unit

Science Media Centre Spain

The journal PLoS One publishes the results of a study that investigates the genetic basis associated with strict vegetarianism and aims to identify possible related genetic variants. The researchers compared the genomes of 5,324 strict vegetarians and 329,455 controls using a genome-wide association study (GWAS). They identified a region of the genome associated with following a strict vegetarian diet that includes genes, such as NPC1 or RMC1, which are important in lipid metabolism and neuronal function. In addition, the authors identify other genomic regions suggestive of a potential role in dietary preferences. 

Although these results suggest that genetic factors are involved in maintaining a long-term vegetarian diet, the study has important limitations. First, in order to identify genetic variants that predispose to initiating and maintaining a vegetarian diet through a GWAS study, it is necessary to analyse the DNA of many vegetarians and compare it with the DNA of a non-vegetarian control group. In this regard, the study includes a total of 5,324 strict vegetarians, which is too small a sample size to obtain conclusive results. For this reason, the results of the study should be considered preliminary until validated in larger samples to determine the role of genetics in dietary preference and maintenance of a vegetarian diet. 

In addition, the authors identify significant differences between the vegetarian group and the control group in terms of Body-Mass Index and socioeconomic status. The vegetarian group consists mainly of women with lower Body-Mass Index and lower socio-economic status. However, the authors do not consider these potential confounding variables in the study, which may be undermining the study results. 

Although the study supports previous evidence suggesting that there is a genetic basis to dietary choice, and that this may be related to differences in metabolism and taste perception, these results should be considered preliminary. If confirmed, the identification of genetic patterns associated with vegetarianism would help to better understand the underlying molecular mechanisms and allow the definition of individualised and effective dietary recommendations based on the genetic profiles of each individual.

The author has not responded to our request to declare conflicts of interest
Genetics of vegetarianism: A genome-wide association study
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