Minor genetic differences impact the ability to utilize the energy of various nutrients

All animals require proteins, carbohydrates, and fats to survive. However, dietary differences between species, populations, and individuals can be significant.

Researchers from Australia, Denmark, and Finland collaborated on an international study to see how individuals from the same population vary in their ability to survive on different diets.

A genetic reference panel of nearly 200 closely linked fruit fly strains (Drosophila melanogaster) was used by the researchers. The flies were fed six different diets, each high in sugar, protein, starch, coconut oil or lard, or a combination of sugar and lard.

The genomes of the strains used in the study were fully mapped, allowing researchers to relate the differences seen in the experiments to particular genetic variations.

The research identified that small genetic variations affected the flies’ capability to use the energy of different nutrients.

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.”

Essi Havula, Study Lead Author and Postdoctoral Researcher, University of Helsinki

Essi Havula added, “The genes that regulate metabolism have been conserved well in evolution, which is why we can learn a lot about human metabolism through studies carried out with fruit flies.”

Genetic analyses uncover several genes that affect nutrient tolerance

The investigators discovered several genes that contributed to the capabilities of flies to tolerate sugar through genetic analysis. Most of these genes are also found in humans and have been linked to obesity and type 2 diabetes as depicted by earlier genome-wide association studies.

Fly studies enable fast and cost-effective functional studies to investigate the genes in depth. Among other things, we demonstrated that the tailless gene (TLX), previously investigated primarily from the perspective of the function and development of the nervous system, is necessary for the normal function of sugar metabolism in flies.”

Essi Havula, Study Lead Author and Postdoctoral Researcher, University of Helsinki

Furthermore, the researchers indicated that in the case of high-sugar diets, the JNK pathway, one of the most crucial stress-signaling pathways, controlled sugar metabolism and storage-fat synthesis.

Havula remarks, “It appears that dietary sugar causes stress to the cells, giving the JNK pathway an important role in how effectively flies tolerate and process sugar.”

Can nutrigenomics assist the development of personalized nutrition?

The majority of the findings, according to the scientists, can be applied to humans as well, though more studies are needed. The research, according to Havula, offers solid evidence that the same dietary recommendations do not always suit everyone.

Havula states, “Research-based knowledge increasingly shows how metabolic responses to diets differ between animal populations and individuals. Traditional dietary recommendations are not necessarily suited to everyone, which explains the continued lack of consensus on a ‘healthy diet’.”

One option is to use nutrigenomics to establish nutrition in a more personalized manner.

Hopefully, in the future type 2 diabetes and many other metabolic diseases can be treated with nutritional planning based on knowledge of individual genomes. This would be considerably less expensive than drug therapies as well as better for the health of individuals in the long run.”

Essi Havula, Study Lead Author and Postdoctoral Researcher, University of Helsinki

Nutrigenomics’ potential extends beyond the treatment of conventional metabolic diseases.

“For example, cancer cells are known to alter their metabolism, extending the potential of nutrigenomics to a wide range of fields,” Havula concludes.