Genetic Test Improves Weight Loss Success With Diets

This is an interesting press release from Interleukin Genetics (ILI) about a genetic test that may allow people to better match their diet to their genetics.  I admit to a bit of skepticism, but here goes: first background information about the test from Interleukin Genetics’s website, and second, the press release. – Ilene 

Weight Management Test 

Human obesity arises from the interactions of multiple genes, environmental factors and behaviors, rendering management and prevention of obesity very challenging.  According to WHO, lack in physical activity and easy availability of palatable foods are the principle modified characteristic of our modern lifestyle that has contributed a lot to the observed obesity worldwide. Despite the fact that we are all exposed to the same environment, not everyone becomes obese.  This could be attributed to individual genetic differences.  Genetics determines an individual’s susceptibility to obesity when exposed to an unfavorable environment as well as the way he/she can respond to diet and exercise. There have been multiple reports that describe the heritability of obesity and also utilize genetic association studies to identify the gene-gene, gene environment and gene-diet interactions involved in the development of obesity. These studies have identified a certain number of single nucleotide polymorphisms (SNPs) that respond to diet and/or exercise.  For example, some SNPs make some people more sensitive to the amount of fat in the diet, while others make some people more resistant to exercise-induced weight loss.

Interleukin Genetics has developed a genetic test panel in the area of Weight Management (WM), which includes the genes that have been validated as significant modifiers of body weight and responsiveness to diet and exercise.  The genes were selected from the Obesity Gene Map Database based on a comprehensive review of the existing scientific literature using very stringent selection criteria by a team of experts from genetics, nutrition, obesity and weight management areas. 

The following process was used to develop the Weight Management genetic test panel:

1. Dr. Louis Perusse, one of the authors of the Obesity Gene Map review (4), provided a list of all genetic variations that were associated with body weight, body mass index, or body fat and had been replicated in at least three clinical studies. Out of hundreds of genes reported in the scientific literature relative to obesity, only 16 met this first criterion.
2. A team of experts then reviewed all evidence on the 16 gene variations for those which met the following:
   • Had proven biological function. In fact, all of the genetic variations in the test panel produce a change in the amino acid structure of the protein and change the activity of the protein.
   • Had a plausible biological role in weight management. For example, some of the gene variations produce a change in the amount of fat absorbed from a meal or change carbohydrate metabolism.
   • Had evidence from clinical studies that individuals with the different genotypes had a differential response to either certain diets or to physical activity.
3. Five variations in four genes met all of the above scientific criteria and are included in the Weight Management genetic test panel.

These gene variations thus impact various pathways that influence body weight and have been associated with elevated risk for obesity and for their ability to differentiate a subject’s response to weight management interventions by genotypes.  Weight management panel genes and variants include:

• Fatty acid binding protein 2 (FABP2) Ala54Thr;
• Peroxisome proliferator-activated receptor-gamma (PPARG or γ) Pro12Ala;
• β2 adrenergic receptor (ADRB2) Arg16Gly and Gln27Glu; and 
• β3 adrenergic receptor (ADRB3) Arg64Trp

The weight management (WM) test panel is designed to assist consumers with effective management of body weight by guiding diet and exercise programs based on genetic differences in metabolism and fat absorption. 

References:

1. 1. International Obesity Taskforce. About obesity 2005. London, United Kingdom: International Obesity Taskforce (2005) (http://www.iotf.org/aboutobesity.asp).
2. Svetkey, L.P., et. al. Comparison of strategies for sustaining weight loss: The weight loss maintenance randomized controlled trial. JAMA (2008), 299, 1149-1148.
3. Yang, W., Kelly, T. and He, J. Genetic Epidemiology of Obesity. Epidem. Rev. (2007), 29, 49-61.
4. Rankinen T, Zuberi A, Chagnon YC, Weisnagel SJ, Argyropoulos G, Walts B, Pérusse L, Bouchard C. The human obesity gene map: the 2005 update. Obesity (2006) 14, 529-644.

Interleukin Genetics, Inc. and Stanford University Report Genetic Test Improves Weight Loss Success With Diets

Clinical Data Presented Today at the American Heart Association Meeting by Stanford Researchers Show Statistically Significant Improvements in Weight Loss and Metabolic Parameters when Diets are Compatible with an Individual’s Genotype

WALTHAM, Mass., March 3 /PRNewswire-FirstCall/ — Interleukin Genetics, Inc. (NYSE Amex: ILI) announced presentation of findings from a retrospective clinical study on weight management conducted in collaboration with Stanford University. The study results and conclusions were presented today by investigators from Stanford Prevention Research Center at Stanford University School of Medicine during an oral presentation titled "Genotype Patterns Predict Weight Loss Success: The Right Diet Does Matter," at the American Heart Association’s Joint 50th Cardiovascular Disease Epidemiology and Prevention – and – Nutrition, Physical Activity and Metabolism conference, being held March 2-5 in San Francisco, CA.

In 2008, Interleukin Genetics and Stanford University began a research collaboration to determine whether individuals who were assigned diets that were appropriate for their genotype could lose more weight than those who followed a diet inappropriate for their genotype, as determined by the Interleukin Genetics proprietary Weight Management Genetic Test. The findings showed statistically significant greater weight loss, metabolic benefit and other improvements when compared to individuals on diets not matched to their genotype.

  Key Stanford findings from the study include:
  --  Individuals on genotype-appropriate diets lost 5.3 percent of body
      weight compared to individuals on diets not matched to their genotype,
      who experienced only 2.3 percent weight loss (p=0.005);
  --  The weight loss differences were even stronger when considering the
      individuals who were trying to follow the lowest carbohydrate (Atkins)
      and the lowest fat (Ornish) diets: 6.8% weight loss for those whose
      genotype matched the diet they were following vs. 1.4% for those not
      matched to their genotype (p=0.03);
  --  The statistical significance of the findings increased when taking
      into account the actual diet habits reported by study participants
      (rather than just the specific diet they were asked to follow);
  --  Improvements in clinical measures related to weight loss (e.g., blood
      triglyceride levels) paralleled the weight loss differences.

"The differentiation in weight loss observed for individuals who followed a diet matched to their genotype versus one that was not matched to their genotype is highly significant in numerous categories and represents an approach to weight loss that has not been previously reported in the literature," said Christopher Gardner, Ph.D., Director of Nutrition Studies at the Stanford Prevention Research Center and an Associate Professor of Medicine at Stanford University. "The potential of using genetic information to achieve this magnitude of weight loss without pharmaceutical intervention would be important in helping to solve the pervasive problem of excessive weight in our society. We are eager to follow-up on this study and to determine the magnitude of health benefits that may result from following a diet that is matched to one’s genotype."…

About the Study

Subjects for the study were chosen from Stanford University’s previously reported A TO Z weight loss study (Gardner et al. 2007 J. American Medical Association), which compared effectiveness of four weight loss diets ranging from very low carbohydrate, to low carbohydrate/high protein, to low fat and to very low fat in overweight/obese pre-menopausal women over a one-year period.

Participants from the A TO Z trial were invited by e-mail and postal mail to provide DNA samples by cheek swab. Genotyping was performed on the DNA samples obtained from 141 female participants. Participants were categorized into three dietary assignment groups including: a) low fat, b) low carbohydrate, or c) balanced in macronutrients by means of predefined genetic patterns from the Inherent Health Weight Management Genetic Test. The primary endpoint analysis compared weight loss for women who were on a diet that was consistent with their genotype category to those individuals on diets not suitable for their genetic pattern. Interleukin Genetics, Inc. reported initial analysis of data from this A TO Z study in September.

…The Weight Management Test is a proprietary genetic test panel developed by Interleukin Genetics that analyzes single nucleotide variations among several functional genes to create macronutrient percentage diet and exercise recommendations for the individual. The test is marketed under the Inherent Health brand (www.inherenthealth.com) and is analyzed in Interleukin Genetics’ CLIA-certified laboratory. For more information please visit www.ilgenetics.com.

Source: Interleukin Genetics, Inc.

Web Site: http://www.ilgenetics.com/