Nutrigenetic-Based Diet Doesn’t Increase Weight Loss, but Adherence May Play Role

Dieting is hard. Some have hoped that genetically tailored diets may make weight loss efforts more effective. But, a small study of 51 obese and overweight adults suggests nutrigenetic-guided diets offer no advantages over standard, balanced diets. However, according to a study published in the September issue of Clinical Gastroenterology and Hepatology, genetic insights may identify individuals most likely to benefit from a traditional, balanced diet weight loss strategy.

Previous genome-wide association studies have identified more than 30 loci associated with obesity, but data remains scarce as to how these genetic variations impact weight loss or metabolic profiles. Yet, there are commercially-available, direct-to-consumer tests making dietary recommendations.

In the current study, participants were randomized to either a nutrigenetic-guided diet (balanced, low-carbohydrate, low-fat, or Mediterranean; n = 30) or a standard balanced diet (n = 21). The Pathway FIT test (Pathway Genomics) was used to make diet selection in the genotype-guided therapy (GT) group.

The researchers found that at eight weeks and at 24 weeks there was no significant difference between the groups in the percentage of participants who lost 5 percent of their body weight (35.0 percent for GT versus 26.9 percent for the standard diet). Further, there were no differences in improvements in biomarkers related to metabolic disease (lipid profile or glucose homeostasis). Both groups had difficulty adhering to the diets. However, adherence to the GT diet correlated with weight loss, while adherence to the standard diet was not tied to weight loss.

“The problem with nutrigenetic-based personalized diet therapy is that recommendations to alter dietary intake remain a poor treatment for obesity because of non-adherence,” writes lead author Karen Frankwich, from University of California, San Diego. (Several authors report financial ties to Pathway Genomics, which funded the study). “Even when given their nutrigenetic information with guided education regarding their nutrigenetic- based diet, GT participants were no more adherent to their diet than those in the standard therapy group.”

Nutrigenetics, the authors say, may still play a role in predicting which individuals would benefit from lifestyle modification and dietary intervention. For those randomized to the balanced diet group based on nutrigenetics, 100 percent of participants lost at least 3 percent of their body weight, compared to 50 percent of participants genotyped to other diets.

The authors acknowledge the likely continued growing interest in genetic-guided therapies for obesity specifically and disease globally. Adoption of nutrigenetics for obesity care must still overcome the practical barriers of cost and non-standard reporting, but the main hurdle for nutrigenetic-guided personalized therapy, they say, is the overall lack of effective remedies for obesity.

Takeaway: Metabolomic profiles in serum may be useful in screening women for early- stage ovarian cancer. While further validation in larger populations is necessary, the researchers say a clinical assay based on the 16 markers is technically feasible.