Individualising the Diet for Obesity based on Genetic Testing Marilyn Glenville PhD Former President, Food and Health Forum, The Royal Society of Medicine
Personalised Nutrition Personalised nutrition has been described as nutritional advice formulated according to an individual s characteristics (Gibney MJ & Walsh MC, 2013, The future direction of personalised nutrition: my diet, my phenotype, my genes. Proc Nutr Soc 72, 219 225)
With Genetic Testing Can Go A Step Further
Genetic Testing Most important to know the genes that we can modify so that we can improve any potentially weak areas and actively improve and help patients take more control of their overall health. Also important for future health because what we learn about a person s genetic make-up can help them to work on prevention.
Genetic Testing and Weight Loss Information about genes can be particularly helpful if someone has failed in all their weight loss attempts so far. Research has shown that if people follow a diet based on their genetic results then they lose 33% more weight than those who are on an untailored diet plan. (Pirastu N et al, 2014, European Human Genetics Conference)
DNA-based dietary advice resulted in: greater understanding of recommendations greater interest in learning more greater motivation to change eating habits
Human Genome Project Completed in 2003 Cost $3 billion Identified all genes in human DNA Approx 25,000 genes 3 billion base pairs
Genetic Variants Differences in nucleotides produce genetic variants Most common variant and most widely studied is the SNP Single Nucleotide Polymorphism
Food Nutrients Nutrigenomics Gene Expression Nutrigenetics Gene Variation Genome
Epigenetics A change in phenotype without a change in genotype
Improved dietary outcomes DNA-based dietary advice is superior to the one-size-fits-all general recommendations
Genetic Tests Easy for patient to collect sample User friendly in terms of the results both for the patient and the practitioner Results focused on diet and lifestyle Results given by a healthcare professional
Nutrigenomix Test Test designed by Professor Ahmed El- Sohemy who holds the Canadian Research Chair in Nutrigenomics at the University of Toronto International Science Advisory Board consists of the most distinguished researchers in the field of nutrigenomics and personalised nutrition
Nutrigenomix Test Nutrient needs eg. Omega 3, vitamin D and the B vitamins Detoxification potential Salt and caffeine sensitivities Risk of lactose intolerance Sensitivity to saturated fat Risk of Coeliac Ideal way to eat Antioxidant needs Eating behaviours What type of exercise suits genetic make-up
Risk versus Response Variants
Risk Variants Risk variants indicate if the patient has a typical or elevated risk for: Poor nutrient metabolism Food intolerances Unhealthy eating habits Exercise behaviour
Response Variants Response variants indicate whether or not the patient will respond to a given dietary or fitness intervention Protein enhanced response Enhanced weight loss response when consuming a moderate to high protein diet
Risk Variants
Vitamin A Dependent on a variant of the BCMO1 gene 50% of population are poor converters of beta-carotene to retinol and won t be able to meet vitamin A needs with beta- carotene
Retinol:beta-carotene ratio by BCMO1 genotype. * Poor conversion of beta-carotene into active vitamin A in those with the risk variant (GG genotype) compared to those with the AA or AG genotype Adapted from Lietzet al. J Nutr. 2011;142:161S-165S.
Vitamin D Low levels of vitamin D linked to osteoporosis, type 2 diabetes, cancer, Alzheimer s, autoimmune problems Some utilise vitamin D more efficiently than others Dependent on a variant of the CYP2R1 and GC genes (Slater et al, J Pharm Pract, 2015, 1-6)
Risk of vitamin D insufficiency by CYP2R1 and GC genotype. * Significantly increased risk of insufficiency for those with the GG or GA genotype of the CYP2R1 gene and the GG genotype of the GC gene. Adapted from Slater et al. J Pharm Pract. 2015:1-6.
Sample Report
Response Variants
Caffeine Interindividual variability in cardiovascular responses to caffeine has a genetic basis. (De Caterina R et al, 2016, J Nutrigenet Nutrigenomics 9, 2-4, 106-115) Some people have increased risk of hypertension and heart attack if they consume 2 cups/d of coffee Dependent on a variant of the CYP1A2 gene (Cornelis et al, JAMA, 2006, 295, 1135-41)
Sample Results
Glycaemic Load Some people have increased risk of type 2 diabetes Dependent on a variant of the TCF7L2 gene (Cornelis et al, Am J Clin Nutr, 2009, 89, 1256-1262)
Risk of diabetes based on TCF7L2 genotype and glycemic load (GL) of the diet. * Percent risk calculated from odds ratios for GT or TT group compared to GG group when the glycemic load of the diet is high. Adapted from Cornelis et al. Am. J. Clin. Nutr. 2009;89:1256-1262.
Eating Habits
Eating Habits Fat taste perception super taster Sugar preference Eating between meals
Eating Between Meals Eating between meals (i.e. snacking) can often be an unhealthy habit Likelihood of eating between meals varies from person to person Dependent on a variant of the MC4R gene Results: Based on individual s genotype for MC4R, can target meal plans Stutzmann et al. Int J Obes. 2009;33:373-378.
Response to a Low Fat Diet
Weight loss (kg) and change in waist circumference (cm) based on total fat intake by TCF7L2 genotype. * Significantly greater weight loss in response to a low fat diet only in individuals with the TT genotype of TCF7L2. Adapted from Grau et al. Am J Clin Nutr. 2010;91:472-479.
FTO Gene Impact on: Physical activity Protein intake Saturated fat
Loss of fat mass (%) of low or high protein calorie-controlled diet by FTO genotype * Significantly greater weight loss in response to a moderate-to-high protein diet only in individuals with the AA genotype. Adapted from Zhang et al. Diab. 2012;61:3005-3011.
Sample Results
Physical Activity
Exercise Motivation to exercise Type of exercise that best suits their genetic make-up Injury risk
Is This The Right Time for DNA-Based Dietary Advice? Scientific evidence is robust (studies replicated) Increasing consumer awareness and demand Information is actionable and personalised Focus on wellness and prevention Improved compliance (evidence from RCTs)
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+ 44 1892 515905 health@marilynglenville.com