by Bianca Garilli, ND
Obesity has both genetic and environmental underpinnings. Research has elucidated key fat-regulating genes, one of which is the fat-mass and obesity-associated (FTO) gene located on chromosome 16q12.2. Single nucleotide polymorphisms (SNPs) on the FTO gene have been associated with an increased risk for obesity.1 Certain obesity-related SNPs have been shown to be specific to a person’s ethnic and racial makeup.
As body mass index (BMI) continues to increase at an alarming rate across the globe, it is clear that genetics are not solely to blame. Lifestyle choices, including dietary habits, have a tremendous impact on the rise in obesity too. What is less well understood, however, is whether strategic environmental/lifestyle changes (e.g. healthy dietary modifications) in those individuals carrying obesity-related genes will yield a positive impact on their BMI. Or are these individuals destined for obesity?
A prospective cohort study published in BMJ investigated whether improving adherence to healthy dietary patterns would interact with genetic predisposition to obesity and influence long-term changes in BMI and body weight.2 Data from 8,828 women from the Nurses’ Health Study and 5,218 men from the Health Professionals Follow-up Study was utilized to follow BMI and body weight changes every four years over a 20-year follow up period between 1986-2006.2 Genetic predisposition to obesity was evaluated for each individual based on a group of 97 SNPs associated with BMI in people of European (79 SNPs) and non-European (20 SNPs) descent. Detailed dietary information was collected through a validated questionnaire every four years during the 20-year follow up.2
Dietary evaluation was based on adherence to one of the following three dietary approaches and scoring assessments:
- The Alternate Healthy Eating Index 2010 (AHEI-2010) – this dietary pattern has consistently been associated with lower risk of chronic disease in clinical and epidemiological investigations2
- The Dietary Approach to Stop Hypertension (DASH) diet – this dietary pattern’s original objective was to lower blood pressure levels but has now been shown to improve many other chronic disease states; it consists of high intakes of fruit, vegetables, legumes, and nuts; moderate amounts of low-fat dairy products; and low amounts of animal protein and sweets; and an emphasis on sodium reduction3
- The (Alternate) Mediterranean Diet (AMED) – this dietary pattern follows a Mediterranean eating pattern but is scored differently than the conventional scoring system; it has been shown that the two scoring systems may be interchangeable within studies.4 The Mediterranean dietary approach consists of eating primarily plant-based foods (fruits and vegetables, whole grains, legumes and nuts) and includes olive oil, herbs and spices, fish and poultry, red wine in moderation, and limited red meat.5
Prior to this publication, no other research had examined the interaction between dietary patterns and the genetic susceptibility to obesity and how these two variables influenced long-term weight gain and BMI.
Key findings from this study include:2
- Improving adherence to healthy dietary patterns as assessed by the AHEI 2010 and DASH diet can counteract part of gene-related, long-term weight gain
- People at high genetic risk for obesity are more susceptible to reap the beneficial effect of improving diet quality on weight loss
- This underlines the importance of improving adherence to healthy dietary patterns in the prevention of weight gain, especially in people with greater genetic predisposition to obesity
Why is this Clinically Relevant?
- Screening for family history and/or genetic susceptibility to obesity will give clinicians and patients information and motivation for adherence to a long-term healthy dietary approach
- Weight-gain should be prevented and addressed as quickly as possible through lifestyle interventions including evidence-based dietary modifications
- Obese individuals with genetic susceptibility to obesity can experience a greater chance of weight loss success by following the dietary patterns based on a whole foods, anti-inflammatory approach like the DASH diet
- Ehrlich AC, Friedenberg FK. Genetic associations of obesity: the fat mass and obesity-associated (FTO) gene. Clin Transl Gastroenterol. 2016;7:e140.
- Wang T, Heianza Y, Sun D, et al. Improving adherence to healthy dietary patterns, genetic risk, and long term weight gain: gene-diet interaction analysis in two prospective cohort studies. BMJ. 2018;360:j5644.
- Fung TT, Hu FB. The Mediterranean and Dietary Approaches to Stop Hypertension (DASH) diets and colorectal cancer. Am J Clin Nutr. 2010;92(6):1429–1435.
- Fung TT, McCullough ML, Newby PK, et al. Diet-quality scores and plasma concentrations of markers of inflammation and endothelial dysfunction. The Am J of Clin Nutr. 2005;82(1):163–173.
- Mayo Clinic: Mediterranean Diet. https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/mediterranean-diet/art-20047801. Accessed March 7, 2018.