Many people in today’s generation have been making significant changes to their diet or lifestyle, often with a particular health or aesthetic goal in mind. Some aim to manage their weight, while others believe it will improve their overall well-being. It is widely known that a specific diet or exercise routine will not yield the same results for everyone, regardless of how long they are followed. Although other factors may contribute, the primary reason for this variability is due to our genetic makeup.

Enter nutrigenomics. Nutrigenomics is a new field in genomics that analyzes how the food (and thus, the nutrients) we intake affect the whole genome, proteome, and metabolome (Sharma & Dwivedi, 2017). In this article, we will learn more about this emerging research area that is rich and multi-faceted, capable of shaping future means of managing health and nutrition. This groundbreaking science is making its way towards a newer, revolutionary form of healthcare as we are now being introduced to an era of personalized nutrition.

What is nutrigenomics?

Nutrigenomics, also called nutritional genomics, is an active research area in genomics that explores the interaction between our genes and food (Neeha & Kinth, 2013a). It is often associated with nutrigenetics, which tackles the influence of genetic variation on dietary response; this is in contrast with nutrigenomics, which explores more on the effect of nutrients and bioactive compounds from food on gene expression (Fenech et al., 2011). According to Fenech et al., the three main factors that make nutrigenomics, and nutrigenetics, an important science are the following:

1. First, different ethnic groups and individuals possess a vast genetic diversity within their inherited genomes which ultimately influences nutrient bioavailability and metabolism.
2. Second, every individual differs in their options and availability of food and nutrients depending on their culture, economic standing, geographic location, as well as taste preferences.
3. Lastly, malnutrition – whether deficiency or excess – can also influence gene expression and the stability of the genome. Excess nutrients can often lead to chromosome or gene sequence mutations, which cause abnormalities in gene expression and later manifest as harmful phenotypes. An example is the evidence of DNA damage through increased intake of riboflavin, biotin, and pantothenic acid found in food (Fenech et al., 2005; Nathaniel Mead, 2007).

The science of nutrigenomics

Nutrigenomics focuses on describing gene products as well as their physiological functions and interactions. Aside from looking at the effects of certain nutrients on the genome, nutrigenomics also observes the influences of nutrients on the proteome and the metabolome, providing a holistic view of these interactions (Neeha & Kinth, 2013b).

Neeha et al. (2013) state that a nutrigenomic approach delivers the following:

• a snapshot of genes that are either switched on or off at a particular time;
• a look into how networks of genes and/or proteins work together to generate the response being observed; and
• a procedure wherein the effect of nutrients on gene and protein expression can be identified.

In addition, the approach is useful in observing certain gene variants that indicate potential nutrient deficiencies, food sensitivities, and the like.

With these, information on how nutrients – and food, in general – influence metabolic pathways and homeostatic control can be realized and obtained. This, in turn, allows researchers to utilize this information to provide preventive measures for chronic diet-related diseases such as type-2 diabetes, cardiovascular diseases, and even obesity (Neeha & Kinth, 2013b).

The following are some of the most common tools and techniques used to carry out a nutrigenomic approach.

• Omics (genomics, transcriptomics, proteomics, metabolomics). Dietary influences on the flow of genetic information (i.e., DNA to RNA and/or protein) can be examined at different levels of the regulation of gene expression via the common omics strategies. Metabolomics and proteomics are both used to locate biomarkers that indicate exposure to specific dietary bioactives while also differentiating individuals depending on their dietary habits (C & M, 2008).
• Systems biology with bioinformatics. Information obtained from omics studies is typically paired with data from other experimental approaches such as in vitro, animal, and human studies. In most cases, clinical and epidemiological studies are also involved to deduce how bioactive compounds from food affect an individual’s health. Apart from this, factors such as demographic, environmental, nutritional, clinical, physiological, and lifestyle are to be taken into account for human analyses. With all these considerations, a more holistic approach via systems biology is usually intended. Bioinformatics helps by interpreting, managing, and storing the large amounts of data to be generated from these experiments (Fenech et al., 2011).
• Genome-wide scans. These scans are typically employed to pinpoint genetic variations that may alter or influence response to diet or food bioactives. This is also referred to as a genome-wide association study or GWAS. Determining the interactions between diet and genes allows individuals to seek more accurate dietary advice while also enabling public health specialists to suggest specific dietary compounds for a specific health outcome (Fenech et al., 2011).  
• Microarray technologies. Microarrays utilize a DNA “chip” to measure the amount of gene expression at a particular time in a sample. This technology can also be used for genotyping. In nutrigenomics, it screens multiple gene samples, all at the same time, providing a holistic picture of different patterns of gene expression, which ultimately allows the interactions between nutrients and genes to be understood (Neeha & Kinth, 2013b).
• Genetic variations. Alterations in the human genome are also viable tools for examination in a nutrigenomic approach. Single nucleotide polymorphisms (SNPs), insertions, deletions, and nucleotide repeats are all modifications that can affect how a person responds to a certain diet or a bioactive food component (Fenech et al., 2011).
• Biomarkers. Exploring dietary effects on various markers such as DNA damage, changes in the epigenome, RNA and protein expression, as well as metabolite alterations help in the diagnosis and prognosis of diseases or health status of individuals (Fenech et al., 2011).

Nutrigenomics through the eyes of the consumer

Nutrigenomic testing is a specific genetic test wherein the results reveal an individual’s nutritional needs that are unique to themselves. Specifically, it shows a person’s genetic (protein) variations that indicate locations of metabolic inefficiency. Typically, healthcare providers that employ this testing screen for single nucleotide polymorphisms or SNPs that serve as biomarkers for altered metabolic function or other health concerns. The results from nutrigenomic testing identify SNPs, while nutritional supplements or other forms of intervention (e.g., lifestyle or diet change, etc.) are advised depending on the patient’s requirements.

How is it done? What are the steps to nutrigenomic testing?

To get an inside view into the process of nutrigenomic testing, the following is a typical step-by-step procedure on how the test is performed. (Note that the initial and most important step before the actual procedure is having done the research on the healthcare provider and the nutrigenomic testing kit to be used.)

1. Provide a sample of DNA. Typically, the kit requires the consumer to perform a cheek swab which will then be sent to the laboratory for analysis.
2. Laboratory analysis. The sample is then analyzed in the lab, where around 70 or more genes are examined. These genes may either be SNPs, insertions, or deletions that have an influence on the individual’s nutritional needs. Usually, these genes are sequenced or genotyped and are compared to databases to determine the clinical significance of the genes. The database then returns information, for example, about the specific SNP found from the sample; the SNP is commonly a biomarker for a chronic disease associated with or has interactions with specific food bioactives or nutrients.
3. Obtaining the results. A report is provided for the consumer that lists all the information obtained from the sample, as well as the implications that it entails. This usually consists of a detailed overview of the individual’s genetic makeup and how certain uncovered genes may influence the consumer’s nutritional or metabolic needs.

What kind of information can one get with nutrigenomic testing?

According to Cleveland Clinic (2022), results from nutrigenomic testing can reveal certain genetic variations that indicate that the patient may be more likely to experience certain health or physiological conditions, including, but not limited to:

• Having high cholesterol or high blood pressure. Experts usually suggest reducing the amount of fat and/or sodium consumption if these conditions – among others – arise.
• Developing cravings for sugary foods. Knowing this information is key to preventing type-2 diabetes and will help the individual to curate an effective meal plan to lessen or satiate these cravings.
• Getting jitters from caffeinated drinks. One may be more likely to experience shaking, heart palpitations, and feelings of nervousness after consuming heavy amounts of coffee or any other caffeinated drink (as compared to others). Healthcare providers may suggest lessening the intake of these drinks as much as possible.
• Observing weight loss on a protein-rich diet. This allows the individual to maintain their current diet confidently, knowing that their body responds well to their intake of carbohydrates, protein, and fat.
• Getting more fat burned during strength training or cardio exercises. Focusing on certain training regimens that are more efficient for an individual may allow improvements to be observable in a much shorter time frame.

What are the next steps?

It is optimal for the consumer to remain in contact with the attending healthcare provider and allow their results to be reviewed alongside them. They can help the individual understand the implications of the results and develop a corresponding personalized plan that may include observing certain diet and/or lifestyle changes or adding nutritional supplements to address nutritional or metabolic deficiencies.

Concluding Remarks

As it stands, a wealth of research is already surrounding nutrigenomics, not only as a science but also as a tool in novel healthcare and nutrition. Genes that have been shown to interact with certain food bioactives or nutrients are also revealed through nutrigenomics. Common genomics tools and techniques such as DNA microarrays, GWAS, and genome sequencing, among others, are also being paired with omics technologies in order to develop precision nutrition strategies that are tailor-made for individuals with a particular disease or disease risk. There is no question that nutrigenomics has vast potential, and this will continue to grow as more research and long-term clinical trials are done on nutrition and metabolism, combined with identifying more disease-specific genotypes.

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