Your genes can influence what you like to eat

You are what you eat—and what you eat can be encoded in your DNA. Studies have shown that your genetics play a role in determining what foods you find delicious or disgusting. But just how big a role they play is difficult to define. “Everything has a genetic component, no matter how small,” says Joanne Cole, a geneticist and assistant professor at the University of Colorado School of Medicine. “We know that genetics play a role in why we eat the foods we do. Can we take the next step and identify regions in the genome? “

Advertising

A new study led by Cole found a step closer. Using large-scale genomics analysis, his team identified 481 regions of the genome, or loci, that are directly linked to eating patterns and food preferences. The findings, which have not yet been peer-reviewed, were presented last month at the annual conference of the American Society for Nutrition. They are building in 2020 Nature Communication a study by Cole and colleagues using data from the UK Biobank, a public database of genetic and health information for 500,000 participants. By scanning the genomes, the new analysis was able to locate 194 sites associated with dietary patterns and 287 associated with foods such as fruit, cheese, fish, tea and alcohol. A better understanding of how genetics affects the way we eat may reveal differences in nutritional needs or disease risks.

“One of the many problems with these genomics studies is that they are very small. They don’t have enough people to really be able to reliably identify genes. This study had a large group of people, so it’s really powerful,” says Monica Dus, an associate professor at the University of Michigan, who was not part of the new research but studies the relationship between genetics and nutrition. “One thing I thought was really cool was that they have so many different qualities that they weigh in terms of food. They had cholesterol, body, social background. “

As research progresses, Dus says such genome analysis may help health care providers—and policymakers—address larger issues affecting food access and health. “Instead of trying to tell people to eat this or that, a more powerful intervention is to link it to ensuring there are no ‘food deserts’ or ensuring there is a higher minimum wage—things that have a wider scale.” impact,” he said.

Advertising

American science spoke with Cole about the new research and what it tells us about the relationship between genetics and diet.

[An edited transcript of the interview follows.]

What do we know about the link between genetics and diet?

Advertising

There has been research about it for over 100 years. Some of the first studies are inheritance studies. Heritability is the amount of genes that contribute to a trait. So traits like height, which are highly genetic, can be 50 to 80 percent. But food probably has very little heredity, or genetic component, because it is influenced by many other important factors such as social status, culture, upbringing and all these things that have nothing to do with how you taste or like food. It wasn’t until new methods came out in the last 15 years or so that we were able to use thousands of relatives. [to study genetic associations with foods]. It helps to remove that dirty part of the environment, and we can get a more accurate estimation of portability.

In 2020 I did a genetic analysis where we scanned the genome to find statistically linked regions. [with foods and diet] and it narrowed those areas. I found that the median genetic component for most food brands was only about 5 percent. So that meant that the main environmental factors –but it doesn’t mean that 5 percent is nothing. Because we have that big data now, we can study that 5 percent.

What did you find in your latest genome analysis?

Advertising

We have found regions in the genome that may influence a variety of food characteristics, including things such as fruit, poultry or fish consumption or different types of coffee or alcohol. We were able to see genetic links to complex eating patterns, such as whether you eat healthy versus unhealthy foods.

Some of the genes that have a strong influence on food, which I find very compelling, are the taste receptor, olfactory receptor and digestive enzyme genes. This includes the taste-taste receptor gene, which is well known to affect the intake of cruciferous vegetables, such as Brussels sprouts. In most of our meals, we eat different foods together, so the foods we eat are often connected. But the olfactory receptor genes we identified were specific. One was associated with cheese and nothing else. There is a special fruit. There is one that is very specific to vegetables. There is one very specific to coffee.

There was one region in the olfactory receptor genome that correlated with how much tea a person drank—which had a really interesting story. Researchers have discovered a genotype, or a different genetic variation, that defines a person’s ability to smell a compound called beta-ionone. If you have one version of this olfactory receptor gene, then you can smell beta-ionone, and if you have the other version, [are less sensitive to the smell or] it does not smell at all. It actually turns out that beta-ionone is in a bunch of things – like tobacco, grapes, orange juice, papaya, peaches, blueberries, spearmint and tea. So this one version of this genotype can dictate – slightly, to a certain extent – whether you smoke, because it is in tobacco, or whether you eat grapes or drink orange juice or tea.

Advertising

How did you manage to exclude other influences, such as environmental and social?

It is a very difficult problem in the field of genetics. One of the major limitations of this link between genetics and diet is that it is strongly influenced by location, educational attainment, socioeconomic status, and income.

How do we know if a gene has an effect on food intake or if it is another trait? A good example would be a gene that increases the risk of diabetes. When you have diabetes, you often change your diet to manage the disease. If we find a gene that links to diabetes, it looks like it’s linked to diet because diabetes is linked to diet.

Advertising

I’ve done an analysis that basically takes a genetic variation that you know is highly associated with, say, fruit consumption and sees if it also has an association with other traits—whether it’s a health trait, like diabetes, or lifestyle, like that. such as socio-economic status. If the genetic variation has a strong correlation with something related to the environment, health conditions or all other external factors that influence the food eaten, it is probably not related to a direct method, such as digestion or taste.

My goal is to find genes that are closely linked to food and not other conditions because I want to see what we can do with those biological pathways. For example, we can change the flavor combination [specific receptors] get a different brain response. Perhaps that could improve people’s adherence to healthy diets for disease control.

Where would you like research to go next?

Advertising

I think there are many studies and analysis that we can do. This is just scratching the surface. Now that we have these regions in the genome, let’s think about and identify those genes that have a direct effect on diet.

Sensory methods are one of my favorite things because I think we can use them as a tool. They become the receptors for the lock and key, and if we create a different key, we can change the bindings. So I think there is a possibility, scientifically, to intervene with them. One of my interests is understanding how having different genotypes, especially these sensory genes, changes the functioning of pleasure and reward areas in the brain. I wonder if we can start to create synthetic or natural compounds that can change the way a person reacts to happiness or to healthy or unhealthy food – if we can use this almost as a supplement to change how people like food or not. Flavor is actually the number one driver of food choice, and among all the other factors that influence whether or not a person eats a certain food. So can we change the perception of taste by understanding biology?

There is also room to test whether certain foods have an effect on various health conditions. Unfortunately, in the field of nutrition, there have been many studies based on correlations. There are studies that say the diet is associated with lowering cholesterol, but most of those studies have failed randomized controlled trials in humans—which are really hard to do and expensive. There is a method in genetics called Mendelian randomisation that mimics randomized controlled trials, so we can test causality and not correlation between different foods and different diseases. By identifying these regions in the genome that are influenced by diet, we can link them together in this way and gain more information about which diseases are caused by certain foods.