Genetic differences impact nutrient tolerance

As no two people are completely identical, it would follow that an individual’s tolerance to stressors, diet, activity and more would vary. New insights from a study out of the University of Helsinki further support the idea that even small genetic differences can impact an individual’s ability to use different nutrients (Nat Comm. 2022. DOI: 10.1038/s41467-022-29183-x).

In the study, Essi Havula, a postdoctoral researcher at the University of Helsinki, collaborated with researchers from Australia, Denmark, and Finland, using a variety of fruit fly (Drosophila melanogaster)—considered a ‘dietary generalist’—to assess the impact of genetic differences in macronutrient tolerance. The team used a collection of more than 200 fruit fly strains derived from a single natural population, and looked at survival on six different diets containing high concentrations of protein, sugar, starch, coconut oil, lard, or a combination of sugar and lard.

Using genetic analysis and functional validation, the team identified several genetic regulators of sugar tolerance, as well as demonstrating a role for the JNK stress-signaling pathway in sugar tolerance and de novo lipogenesis, and a role for the tailless gene (TLX) in regulating sugar metabolism via insulin-like peptide secretion and sugar-responsive CCHamide-2 expression. Many of these genes are also found in humans and may be linked to blood sugar and insulin sensitivity.

In a statement on the findings, Havula noted: "Unexpectedly we found that the fruit fly strains differed considerably, for example, in their ability to survive on a high-sugar diet. What makes this particularly surprising is the fact that the food consumed by fruit flies in nature contains a lot of sugars.”

According to the researchers, most of the findings can be applied to humans as well, even though further research is still needed. "Research-based knowledge increasingly shows how metabolic responses to diets differ between animal populations and individuals,” Havula stated. “Traditional dietary recommendations are not necessarily suited to everyone, which explains the continued lack of consensus on a 'healthy diet'."

As the researchers conclude in their paper: “Personalized nutrition as a preventive health strategy is still in its infancy. Isolating genes that moderate an individual’s response to different nutrients will have an enormous impact on public health, with the potential to facilitate a revolution in the use of food to treat and prevent disease. This study moves us one step closer to this goal and informs further studies on the mechanistic basis for metabolic disease.”