Genetic obesity predisposition no barrier to healthy diet benefits
medwireNews: Eating a healthy diet is of particular benefit for people with high genetic risk for obesity, report researchers in The BMJ.
Among 8828 women in the Nurses’ Health Study and 5218 men in the Health Professionals Follow-up Study, each additional 10 alleles conferring genetic risk for obesity were associated with a 4-year BMI increase of 0.02 kg/m2 and bodyweight increase of 0.05 kg.
However, “[t]he observed genetic effects were modest in magnitude, compared with lifestyle risk factors,” stress Lu Qi (Tulane University, New Orleans, Louisiana, USA) and study co-authors.
And this risk varied according to participants’ adherence to a healthy diet, assessed by the Alternate Healthy Eating Index 2010 (AHEI-2010). Those in the lowest third for healthy diet adherence had a 4-yearly increase of 0.07 kg/m2 per 10 additional risk alleles for BMI, equivalent to 0.16 kg, compared with a reduction of 0.01 kg/m2 (0.02 kg) among those in the highest third.
“Because changes in body mass index and body weight are essentially cumulative during the life course, the long term effect size would be substantial,” the researchers emphasize.
Conversely, increases in healthy diet adherence were associated with reductions in BMI and bodyweight, and this effect was more marked among participants with higher genetic risk scores. The reduction in BMI per standard deviation increase in AHEI-2010 was 0.12 versus 0.18 kg/m2 among those in the lowest versus highest thirds of genetic risk, corresponding to 0.35 and 0.50 kg reductions in bodyweight.
In an accompanying editorial, Louisa Ells (Teesside University, Middlesbrough, UK) and co-authors say that these “encouraging” findings “support the importance of national and international guidelines that define and promote adherence to healthy dietary patterns, and help to dispel misconceptions that a genetic predisposition will inhibit successful weight management.”
The editorialists conclude: “The advantages of consuming a healthy diet are clear, but it is important to acknowledge the challenges of achieving this in an obesity promoting environment in which unhealthy food options are cheap, readily available in large portions, and heavily marketed.”
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