In a recent study published in PLoS ONE, researchers identified genetic loci related to strict vegetarianism in United Kingdom Biobank (UKB) participants using a genome-wide association study (GWAS).

Study: Genetics of vegetarianism: A genome-wide association study. Image Credit: natalia bulatova / Shutterstock.com

Background 

Vegetarianism has been practiced for hundreds of years by various religions, including Hinduism and Buddhism, in addition to certain sects in ancient Greece. The health advantages of a vegetarian food regimen have been established; nonetheless, there are also concerns about potential dietary deficiencies.

Despite its increasing popularity, only a tiny percentage of the worldwide population practices strict vegetarianism. Interestingly, there appears to be a genetic aspect influencing dietary decisions. Further research is required to higher understand how genetics may contribute to a person’s ability to adopt and maintain a vegetarian lifestyle.

Concerning the study

The present study utilized participant data from the UKB, a health research database that comprises about 500,000 individuals between 40-69 years of age. The UKB recorded data using physical examinations, sample collections, and detailed questionnaires, which included questions on dietary habits to discover vegetarians.

UKB operates with approval from the North West Multi-center Research Ethics Committee (MREC), thereby allowing researchers to make use of its data without in search of additional ethical clearance. All data are entirely anonymized, and all study participants initially provided electronic consent with the peace of mind that they might opt out at any time.

UKB performed genotyping and quality control on its ethnically diverse participants using the UK Biobank Lung Exome Variant Evaluation (UK BiLEVE) and UK Biobank Axiom Array (UKB Axio). Genotyped data were then pre-phased to find out individual haplotypes, followed by imputation using various reference panels. Consequently, the imputed data consisted of over 93 million genetic markers.

Additional in-house qc were applied after receiving the info. From the initial pool, 161,655 samples were excluded attributable to various criteria, ultimately making 340,754 samples available for evaluation. Genetic variants that didn’t meet specific quality criteria were also excluded, which led to 9,740,199 variants available for the study.

For phenotype processing, quality-controlled data were classified into vegetarians and non-vegetarians. Data for determining dietary habits were collected using two distinct questionnaires. Based on stringent screening criteria, 5,324 participants were identified as vegetarians and 329,455 as controls.

The study used Scalable and Accurate Implementation of a GEneralized mixed model (SAIGE) for genome-wide evaluation, which considered aspects like age and sex. Additional analyses utilized the Functional Mapping and Annotation platform (FUMA).

Study results 

In the current study, individuals defined as vegetarians were those that had not consumed animal flesh or products derived from it for a minimum of one yr. Their selection was based on data from the touchscreen questionnaire, which assessed food regimen over the past yr and was accomplished by roughly 500,000 respondents on 4 occasions, in addition to the 24-hour recall questionnaire, which detailed food intake from the day prior to this and was accomplished by about 110,000 participants five times.

In comparison with controls, vegetarians were typically younger, female, had lower body mass indices and were from less affluent backgrounds. GWAS for vegetarianism exhibited mild inflation, possibly attributable to case-control imbalances, despite rigorous measures to make sure accurate evaluation.

A gene-property evaluation was executed to discern the particular tissues affected by the phenotype, highlighting the importance of 30 general tissue types. Several genes related to vegetarianism were found to be particularly energetic within the brain. SNPs linked with vegetarianism were also related to traits related to lipid metabolism and brain functioning.

One significant single nucleotide polymorphism (SNP) on chromosome 18 was identified. Several SNPs within the vicinity that were closely related to this SNP were also identified inside genes like RIO kinase 3 (RIOK3), NPC intracellular cholesterol transporter 1 (NPC1), required for meiotic nuclear division 1 homolog (RMC1), and transmembrane protein 241 (TMEM241).

NPC1 was of particular interest, because it is linked with SNPs having the very best likelihood of being functionally significant. This gene plays a pivotal role in the inner movement of cholesterol and glycolipids.

Disruptions in NPC1 cause most Niemann-Pick disease type C cases, a condition marked by cholesterol accumulation in tissues that primarily causes neurological symptoms. These findings indicate that vegetarianism might need connections with lipid metabolism and its influence on brain activity. 

Taken together, there have been 202 significant variants related to 11 genes possibly influencing vegetarianism. Further scrutiny of the GWAS data using the FUMA platform led to the identification of 37 genomic risk locations for vegetarianism and linked 842 SNPs and 59 genes to those regions.