How your brain determines what foods you are more likely to eat

What foods you eat and how well you follow certain diets could be written into your DNA.

Being a vegetarian might be driven by your genes, scientists have suggested.

Researchers at Northwestern University in Chicago, Illinois, analyzed the genetics of 350,000 people to study if genetics played a role in adherence to a vegetarian diet.

Data included DNA from 5,000 strict vegetarians and 300,000 non-vegetarians.

They found three genes strongly linked to a vegetarian diet, while 31 others were potentially linked to a plant-based lifestyle and found vegetarians are more likely than non-vegetarians to have different variations of these genes.

Researchers said the genes were mostly linked to the digestion of lipids, or fats, suggesting they helped vegetarians to better extract essential fats from plants sources and deterred them from returning to meat.

Three genes were linked to a vegetarian diet, while 31 others were potentially linked to a plant-based lifestyle, the researchers said (stock image)

Dr Nabeel Yaseen, an emeritus professor of pathology who led the research, told CNN: ‘At this time, what we can say is that genetics plays a significant role in vegetarianism and that some people may be genetically better suited for a vegetarian diet than others.

‘A large proportion of self-described vegetarians actually report consuming meat products when responding to detailed questionnaires.

‘This suggests many people who would like to be vegetarian are not able to do so, and our data suggest that genetics is at least part of the reason.’

The genes scientists detected may be involved in coding for enzymes that were the right shape to break down fats from plants. These are a different shape from enzymes that broke down fats from animals.

Researchers said this would avoid nutrient deficiencies in the body, which could have negative effects on areas of the body such as the brain, which is made up of 60 percent fat and requires lipids to support its structure and communication between cells.

A deficiency can lead to poor memory and learning and a higher risk of depression and anxiety. 

In their paper, published in PLOS One, they likened the ability to break down fats from plants to people who are able to easily digest caffeine or alcohol.

They said those who were not as able to break down these substances were more likely to suffer adverse effects and, as a result, consume less of them.

The variations on the ‘vegetarian genes’ — called TMEM241, RIOK3, NPC1 and RMC1 — were not present in meat eaters.

The study was based on data from the UK Biobank, a major database of the habits and genetics of 500,000 individuals.

This paper defined vegetarians as those who had not eaten any animal products within the past year, which also included seafood or products that use animal flesh such as lard.

Vegetarians were shown to be mostly women, younger in age, to have a lower body mass and to have a lower socioeconomic status.

In addition to the three genes strongly linked, results also showed 31 genes the researchers said were potentially linked to a vegetarian diet.

Most of these were also associated with how the body breaks down fats.

Plants and meat have fats with differing complexity, meaning they require different enzymes in order to break them down.

Dr Yaseen added: ‘We speculate that this may have to do with genetic differences in lipid metabolism and how it affects brain function, but more research is needed to examine this hypothesis.’

About six perent of Americans — or 19million people — are vegetarians, surveys suggest.

But many need to take essential supplements — such as vitamin B12, zinc and iron — in order to avoid any adverse health effects from their meatless diet.