Researchers from Italy have begun to identify the genetic mechanisms behind taste perception and food preferences, which they say could open the doors for personalized nutrition plans that could not only be effective for weight loss, but also for disease prevention.
The research team, including Dr. Nicola Pirastu and Dr. Antonietta Robino of the University of Trieste and the IRCCS Burlo Garofolo Institute for Maternal and Child Health in Italy, recently presented their theory at the annual meeting of the European Society of Human Genetics (ESHG).
According to the investigators, an understanding of why people prefer tastes of certain foods and the ability to create a personalized eating plan will lead to healthier aging and a better overall quality of life.
As such, the team have conducted a series of studies in an attempt to identify the genes and pathways involved in taste perception and determine why people prefer the taste of certain foods over others.
"To date most studies have focused on specific taste receptors, especially bitter ones, and this has been partly successful in an attempt to understand the genetics behind the perception of specific compounds, such as caffeine and quinine," says Dr. Robino.
"Our work has expanded these studies to the whole genome, with the goal of clarifying which specific genes drive individual differences in taste perception and food preferences."
Team identifies 17 genes linked to specific food preferences
For one study, the team analyzed the genomes of 2,311 Italian individuals, and an analysis of a further 1,755 individuals from other European countries and Central Asia was conducted in order to validate their findings.
From this, the researchers identified 17 genes that were associated with a preference for specific foods, including bacon, artichokes, coffee, dark chocolate, blue cheese, chicory, ice cream, liver, oil or butter on bread, orange juice, plain yogurt, white wine and mushrooms. The team was surprised to find that none of these genes were associated with those related to smell or taste receptors.
However, the researchers note that further studies are needed to determine what food characteristics these genes pick up on in order to develop a preference. For example, Dr. Pirastu notes that the HLA-DOA gene indicates a preference for white wine, "but we have no idea which of the characteristics of white wine this gene influences," he says.
"Our studies will be important for understanding the interaction between the environment, lifestyles, and the genome in determining health outcomes," he continues.
"Although there has been a lot of work on food-related diseases, such as obesity, this has rarely taken food preferences into account. This is a major limitation which our work attempts to remedy, and as yet we have only really scratched the surface of this issue."
Response to salt linked with DNA variation on KCNA5 gene
In another study, the researchers analyzed 900 healthy adults from northeastern Italy and monitored their response to the taste of salt.
The team found that participants' response to salt was associated with a DNA sequence variation on KCNA5 - a gene known to be associated with taste receptors in mammals.
According to the researchers, this association may help in determining the differences in salt intake between individuals, which may have important implications for health. Excessive salt intake is associated with increased risk of hypertension and cardiovascular disease.
Dr. Robino says:
"Identifying the receptor associated with individual differences in the perception of salt could help us better understand how chemosensory differences can interact to influence and predict food choices and hence human nutritional behavior.
This could also play an important role in the development of salt substitutes, in which there is a growing commercial interest."
Following a gene-based diet led to 33% higher weight loss
In other research, the team assessed 191 obese individuals who they divided into two diet groups.
For one group - which the researchers deem the "test" group - the participants were required to follow a personalized diet plan that the researchers had created based on 19 different genes they had identified in previous research. The other group acted as controls.
"We devised a standard weight-loss diet subtracting 600 calories from individual nutritional needs, and analyzed DNA from the test group for 19 genes known to affect different metabolic areas and taste," Dr. Pirastu explains.
"We then modulated the diets according to individual genetic profiles. For example, people whose genetic profile showed that they had less efficient lipid metabolism were given fewer lipids in their diet, but we kept the overall amount of calories the same for everyone."
At the end of the 2-year study period, the researchers found that participants who followed the gene-based diet lost 33% more weight and had a higher percentage of lean body mass, compared with participants in the control group.
The team concludes that the primary factor that drives food choice, nutrition and diet-related diseases is food preference. Understanding what affects food preference, the researchers say, may have important implications for health.
The researchers refer to a recent study carried out by French investigators, which found that people who have a liking for fat follow a completely different diet than those who do not like it.
"So something as simple as measuring fat liking can provide us with a great deal of information," adds Dr. Pirastu. "Understanding the genetics of these traits will open new possibilities for the development of personalized diets and of functional foods aimed at improving people's health and therefore their quality of life."
Medical News Today recently reported on a study from St. Michaels Hospital in Canada, which suggested that a vegan, low-carbohydrate diet may reduce the risk of heart disease.