Is eating meat in your genes?

A hamburger or a beet burger, which would you choose? And if you are or would be identical twins: would your genetically identical co-twin make the same choice?

In an earlier RAD blog, I announced a project on food preference, and whether hereditary predisposition plays a role in this, see ¹. The results of this project have since been published ². We asked monozygotic twins (genetically identical) and dizigotic twins (sharing half of their genes) about their preference (on a scale of 0 strong dislike to 10 strong preference) for dozens of foods, such as broccoli, shrimps, blue cheese or sausages. We found that there were clusters of foods that some people scored high in and other people lower in, namely: meat, fish, fruits, vegetables, savory snacks, sweet snacks, spices, and (alcoholic) beverages. For the meat and fish clusters, it appears that the role of hereditary predisposition varies between 41% and 60%. In addition, while unique environmental factors play a role (40-59%), the shared family environment does not. I would expect that liking (or disliking) a certain type of food would also lead to higher (or lower) consumption of that type of food. There are increasing numbers of Dutch people (8 in 10) who do not eat meat on a daily basis, and 5% of Dutch people do not eat meat at all ³. Could hereditary predisposition also play a role in this, or is this influenced more by the environment? There are no data available (yet) from the Netherlands (but keep an eye on RAD blog…). The only published study worldwide is based on data from Finnish twins. The results are summarized below.   CORE Hereditary predisposition plays a large role (76%) in not eating meat (vegetarianism). The authors themselves call this their most striking finding. Future studies should identify the specific genetic factors (e.g. genes for taste receptors or personality) in order to learn more about the underlying mechanism.   RESEARCH METHODS WHAT? For this sci-fly, the focus is on 1 of the research questions, namely: How large is the role of genetics, shared family environment, and unique environment in vegetarianism? WHO? 9564 Finnish twins and their siblings from 4887 families (age 18-58 years). HOW? An online questionnaire during the period November 2018-January 2019. In addition to other food-related questions, the survey asked, “Are you a vegetarian/vegan?” (response options: yes/no). By comparing the monozygotic and dizygotic twin pairs, mathematical models can be used to estimate the relative contribution of: genetic factors, shared family environment and unique environment (combined 100%).   FINDINGS

  The left image shows that the monozygotic (MZ) twin pairs are much more similar in terms of whether or not they eat meat (similarity 0.76) than the dizygotic (DZ) twin pairs combined with “normal” siblings (similarity 0.36). A similarity of 0 means there is no similarity at all and a similarity of 1 means there is complete similarity. The picture on the right shows the results of the twin analysis. It shows that genetic factors plays a large role (76%) in whether or not we eat meat. The shared family environment during childhood plays no role, and other environmental influences (outside the family) determine 24% of the differences in eating or not eating meat.   DETAILS Ç. Çınar, L.W. Wesseldijk, A.K. Karinen, P. Jern, J.M. Tybur. Sex differences in the genetic and environmental underpinnings of meat and plant preferences. Food Quality and Preference 2022 98, 104421   This sci-fly was written by Prof. dr. Jacqueline Vink (Behavioural Science Institute, Radboud University) for RAD blog, the blog about smoking, alcohol, drugs & diet.   REFERENCES/SOURCES: ¹ Drieling dol op Chinees eten – is voedselvoorkeur erfelijke bepaald? RAD-blog 23 mei 2019 door Jacqueline Vink. https://rad-blog.com/2019/05/23/drieling-dol-op-chinees-eten-is-voedselvoorkeur-erfelijk-bepaald/ ² Vink JM, van Hooijdonk KJM, Willemsen G, Feskens EJM, Boomsma DI. Causes of Variation in Food Preference in the Netherlands. Twin Res Hum Genet. 2020 Aug;23(4):195-203 ³ Vlees geen dagelijkse kost voor 8 op de 10 Nederlanders. 09-06-2021. Centraal Bureau voor Statistiek. https://www.cbs.nl/nl-nl/nieuws/2021/23/vlees-geen-dagelijkse-kost-voor-8-op-de-10-nederlanders