The results, published in the Journal of the Academy of Nutrition and Dietetics, found that those with a greater genetic risk ‘score’ for obesity and whose calorie intake was made up of a greater amount of saturated fat, had higher Body Mass Indexes (BMI).
Professor José Ordovás, the senior researcher behind the study, said it was already well established that certain genes interacted with dietary fat and influenced BMI - the ratio of weight to height. "In the current study, we analysed dozens of variants of those genes and other genes frequently associated with obesity risk and saw that, while total fat intake was related to higher BMI, people who were genetically predisposed to obesity and ate the most saturated fat had the highest BMIs," he said.
The researchers developed a genetic risk rating system for obesity using 63 obesity-related gene variants they had identified. This scoring system was then applied to 2,818 white, American men and women from two previous heart disease prevention studies.
Sat fat connection
In the first study 34.5% of the participants were obese and 28% in the second. In both populations total fat, saturated fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids intakes were higher and carbohydrate intake was lower in obese participants when compared with non-obese participants.
Dietary intakes were estimated with questionnaires. In the study’s concluding remarks, the researchers admitted that the results were preliminary, and they could not deny the possibility that saturated fatty acids may represent a, “marker for poor dietary quality or other substandard lifestyle habits, either of which can increase obesity risk”.
The researchers said more research was required into the role of saturated fat intake in the development of obesity and this link with gene function. However they added that some clinical models using rodents had suggested that saturated fat may influence the area of the brain that tells us when we're full, while other studies have made observations of an interference with satiety.
What’s the score?
The researchers said the findings suggested that a strategy of personalised nutrition could be useful for those with such a genetic predisposition to obesity, established through this scoring system.
“If further research can clarify a relationship between obesity related genes and saturated fat, people with higher scores would have even more incentive to follow advice to limit their saturated fat intake as part of an obesity prevention strategy," Ordovás said.
Source: Journal of the Academy of Nutrition and Dietetics
Published online ahead of print, doi: 10.1016/j.jand.2014.03.014
“Saturated Fat Intake Modulates the Association between an Obesity Genetic Risk Score and Body Mass Index in Two U.S. Populations”
Authors: P. Casas-Agustench, D.K. Arnett, C.E. Smith, C.Q. Lai, L.D. Parnell, I.B. Borecki, A.C. Frazier-Wood, M. Allison, Y.D. Chen, K.D. Taylor, S.S. Rich, J.I. Rotter, Y.C. Lee and J.M. Ordovás