Genetic background has an effect on the metabolism of essential polyunsaturated fatty acids, alpha-linolenic acid and linoleic acid, a recent study from the University of Eastern Finland shows.
Supplementing the diet with camelina oil rich in alpha-linolenic acid, or with sunflower oil rich in linoleic acid altered the concentrations of the metabolites of these fatty acids in the body; however, changes depended on study participants FADS1 genotype. The study was conducted among carriers of two different FADS1 genotypes.
“Camelina oil increased the plasma concentration of eicosapentaenoic acid produced from alpha-linolenic acid in only one of the genotypes studied,” says researcher and first author Topi Meuronen from the University of Eastern Finland.
Both diet and genes have been found to have an effect on the concentrations of different fatty acids in the body. the FADS1 gene regulates the metabolism of polyunsaturated fatty acids, and the FADS1 The genotype has previously been associated with disorders of glucose and lipid metabolism, and with the risk of type 2 diabetes.
Linoleic acid and alpha-linolenic acid are essential fatty acids that are not produced by the human body, that is, they must be obtained from food. Linoleic acid is the most common dietary fatty acid in the omega-6 family. Alpha-linolenic acid, on the other hand, belongs to the family of omega-3 fatty acids. Varying concentrations of both are found in vegetable oils, seeds, and nuts. Of the vegetable oils, sunflower oil is particularly rich in linoleic acid. Camelina oil and flaxseed oils, on the other hand, are rich in alpha-linolenic acid.
High intake and plasma concentration of linoleic acid have been associated, for example, with a lower risk of type 2 diabetes and cardiovascular disease, but the association of alpha-linolenic acid remains unclear. As metabolites of linoleic acid and alpha-linolenic acid, the body produces lipid mediators that are important, but some of them are also pro-inflammatory.
In the new study, the researchers explored whether point mutations of rs174550 in the FADS1 gene modify the effect of alpha-linolenic acid and linoleic acid on the composition of plasma fatty acids, and the concentrations of lipid mediators derived from polyunsaturated fatty acids. bearers of two different FADS1 Genotypes were recruited from men who participated in the Metabolic Syndrome in Men, METSIM study. They supplemented their diet with 30-50 ml of camelina oil or sunflower oil daily for eight weeks.
Our research design, i.e. recruiting subjects on the basis of their genetic background, has proven effective in investigating gene-diet interactions.”
Maria Lankinen, Postdoctoral Researcher, University of Eastern Finland
The body can make eicosapentaenoic acid from alpha-linolenic acid and arachidonic acid from linoleic acid, for example. These long-chain fatty acids and the lipid mediators produced from them are involved in many functions in the body, such as the inflammatory response and vascular function.
The study showed that the FADS1 The genotype plays an important role, for example, in the efficiency with which essential fatty acids are converted to arachidonic acid and eicosapentaenoic acid. the FADS1 genotype also affected the concentrations of metabolites derived from them.
The use of camelina oil rich in alpha-linolenic acid increased the concentration of eicosapentaenoic acid and lipid mediators derived from it in only one of the genotypes studied. In contrast, the use of linoleic acid-rich sunflower oil did not increase the concentration of arachidonic acid or its derived lipid mediators in carriers of any of the genotypes.
“The changes we observed in the plasma concentration of eicosapentaenoic acid were at the same level as in our previous study, where people ate fatty fish that contained eicosapentaenoic acid. However, an interesting observation is that when camelina oil was used, the changes occurred in only one of the genotypes studied,” says Meuronen.
According to the researchers, the results give rise to the question of whether it is possible to give more and more individualized guidelines on the intake of alpha-linolenic acid and linoleic acid. However, more research is needed.
The study was carried out in collaboration with the Karolinska Institutet, and the findings were published in Research in Molecular Nutrition and Food.
Meuronen, T. et al. (2022) The FADS1 rs174550 genotype modifies the responses of n-3 and n-6 PUFAs and lipid mediators to diets rich in alpha-linolenic acid and linoleic acid. Molecular Nutrition and Food Research. doi.org/10.1002/mnfr.202200351.