By Michaela Copp
Food affects people differently. While one individual can enjoy and easily digest a bagel, another individual with celiac disease will experience an autoimmune response after the first bite. What leads to this discrepancy? Changes in these individual’s genomes.
Back to the Basics:
Humans have approximately 3 billion DNA pairs contained within 23 pairs of chromosomes. These DNA pairs carry the genetic information and instructions critical for growth, development, functioning, and reproduction. Genetics is the study of how this DNA is passed on through generations, how (and why) variations occur, and how these variations are expressed.
The Human Genome Project, launched in 1990 and completed in 2003, sought to identify and sequence every gene that make up human DNA. The Human Genome Project found that humans share 99.9% identity between their genomes, and the remaining 0.1% code for the unique features that distinguish people from one another (i.e. lean muscles, curly hair, green eyes). These differences, among other factors, account for discrepancies in nutritional requirements and the risk of developing chronic diseases. These differences also reveal the antiquated nature of using recommended daily allowances for the general population, and the growing need for establishing individual dietary requirements. Ultimately, sequencing the human genome led to the emergence of the fields of nutrigenetics and nutrigenomics.
Nutrigenetics vs. Nutrigenomics:
Simply put, diet can influence genetics, and genetics can influence diet. Nutrigenetics investigates the effect of genetic variations on dietary response (i.e. how your DNA influences your body’s response to nutrients). Conversely, nutrigenomics studies the role of nutrients and bioactive food compounds in gene expression (i.e. how nutrients affect your gene expression).
The fundamental hypotheses of these fields are (1) nutrition may impact health outcomes by affecting the expression of genes in metabolic pathways, (2) the effects of nutrients on health is dependent on inherited genetic variants that alter the uptake and metabolism of nutrients, and (3) better health outcomes can be obtained if nutritional requirements are personalized to an individual’s genetic characteristics.
Applications of Nutrigenomics and Nutrigenetics Research:
Nutrigenomics and nutrigenetics can help individuals understand how differences in their genome influence their bodies’ response to certain nutritional supplements. Nutritional experts are learning to analyze information on individual genes, diets, lifestyles, and environments to develop nutritional strategies specific for certain genetic makeups. A deep dive into someone’s genetic variants can uncover information such as…
- Eating Behaviors: why they may have more of a sweet tooth or struggle to feel full
- Food Reactions: how their body reacts to certain foods, such as lactose intolerance
- Matching Diet: how their body reacts to a high fat diet or a high carbohydrate diet
- Nutritional Needs: identifying and supplementing vitamins their body may struggle to metabolize
- Metabolic Health Factors: how diet affects their cholesterol levels and if they are more prone to elevated LDL cholesterol
Understanding the influence of gene-nutrient interactions and designing appropriate diets for specific genotypes has the potential to optimize individual health, diagnose and treat genome instability, and prevent the onset and progression of diseases.
While there is a large amount of excitement surrounding nutrigenomics and nutrigenetics, important questions that should be considered as these fields progress are: How costly will personalised nutrition and counseling be? Will this approach be a luxury limited to people with money and education? Will people stay motivated to adhere to their tailored diet? And does personalized nutrition have a feasible chance at improving public health and combating the obesity epidemic?
Peer-edited by Gabrielle Dardis