A study on fruit flies has indicated that genetic interaction with diet has a greater impact on body weight than diet alone, which the researchers say can help explain different reactions to similar diets.
Published in the July issue of Genetics, the study adds weight to the theory of personalised nutrition, which suggests that the benefit of nutritional compounds varies for different people.
“This study strongly suggests that some individuals can achieve benefits from altering their dietary habits, while the same changes for others will have virtually no effect,” write the researchers.
Different genetic lines
Led by Laura Reed, Ph.D, from the Department of Genetics at North Carolina State University, the researchers studied 146 different genetic lines of fruit flies to contrast quantitative genetic mechanisms with respect to weight gain.
The flies were fed four different diets: nutritionally balanced, low calorie, high sugar, and high fat. Researchers then measured a variety of metabolic traits, including body weight, in each group.
Findings indicated that diet alone made a small contribution to the total variation in metabolic traits, while genotype and genotype interactions with diet made “very large” contributions.
Flies in some of the genetic lines were “highly sensitive” to their diets, as reflected by changes in body weight, while flies of other lines showed no change in weight across diets.
For several metabolic traits, genotype-by-diet interactions accounted for far more variance (between 12 and 17 per cent) than diet alone (1–2 per cent), and in some cases have as large an effect as genetics alone (11–23 per cent), reported the researchers.
One size doesn’t fit
"There is no one-size-fits all solution to the diseases of obesity and type-2 diabetes," said Reed.
"Each person has a unique set of genetic and environmental factors contributing to his or her metabolic health, and as a society, we should stop looking for a panacea and start accepting that this is a complex problem that may have a different solution for each individual."
Source: Genotype-by-Diet Interactions Drive Metabolic Phenotype Variation in Drosophila melanogaster
Genetics, Jul 2010; 185: 1009 - 1019.
Authors: Laura K. Reed, Stephanie Williams, Mastafa Springston, Julie Brown, Kenda Freeman, Christie E. DesRoches, Marla B. Sokolowski, and Greg Gibson