Nutritional Genomics

Nutrigenomics is the study of how food interacts with our genes to influence health outcomes. This relatively new field is rapidly evolving, allowing us to gain a better understanding of the microscopic interactions between nutrients and gene expression.

Genetic variations can actually impact how we digest, absorb, and metabolize nutrients. Nutrients can also affect how genes are expressed. We can use this research in the clinical setting, allowing us to implement a more personalized approach to nutrition and disease prevention. This article will address what nutritional genomics is and how we can use it in practice to effectively manage health and disease.

Nutrigenomics and nutrigenetics

Let’s discuss the differences between nutrigenomics and nutrigenetics. Both of these concepts involve the interplay between the food you eat and the genes you have. However, although they sound similar – nutrigenomics and nutrigenetics are actually two very different principles.

Nutrigenomics

Nutrigenomics explains how foods impact our genes and how they are expressed. In short, nutrients can turn certain genes on and off. And because these genes can impact our health, nutrients (and the food we eat) play an integral role in our health and wellness.

Nutrigenomics can work either for or against us, depending on what you eat. For example, some foods can “turn on” genes that decease inflammation. Alternatively, other foods may “turn on” genes that perpetuate insulin resistance or cardiovascular disease (1,2).

Nutrigenetics

Nutrigenetics is a bit different. Nutrigenetics is a concept that focuses on how somebody’s DNA affects their body’s response to certain foods. For example, differences in genes can impact how well nutrients are absorbed, metabolized, and utilized. A popular example would be lactose intolerance, in which a certain genetic variation causes decreased lactase production. As such, someone with this gene would have trouble digesting dairy (1,3).

How Nutrients Affect Gene Expression

Epigenetics

As discussed, nutrients can do more than provide the body’s building blocks and energy – they actually can control gene activity. To further understand this process, it’s important to understand the concept of epigenetics. Epigenetics refers to gene changes that don’t involve changes to a DNA sequence but instead include modifications like DNA methylation, histone  modification, and non-coding RNA activity. These changes are caused by environmental factors, like diet (4).

Turning genes “on” or “off” via diet

Because of epigenetics, certain dietary patterns can essentially turn genes “on” or “off”. A great example of this is with caloric restriction. Periods of calorie deficit are associated with changes to gene expression related to metabolic regulation and aging. Alternatively, high-fat diets can activate inflammatory gene pathways (5).

And believe it or not, maternal nutrition can also have epigenetic effects on offspring. In an animal mouse model, for example, mice were given dietary methyl donors throughout pregnancy. In doing so, the agouti gene was switched off, causing healthier and leaner offspring (6).

Real-World Examples

While the link between gene expression and nutrition makes sense in theory, it has real-life implications that you may have actually experienced yourself. There are several common conditions where we can see the interaction between genes and nutrients at play. These include lactose intolerance, folate metabolism, and omega-3 fatty acids.

Lactose Intolerance

As previously mentioned, lactose intolerance is one of the most common examples of genetic differences impacting nutrient metabolism. Some people have difficulty digesting lactose, which is sugar contained within milk. Whether or not this happens depends on expression of the LCT gene, which is what encodes the lactase enzyme. 

We tend to have high levels of lactase after birth, but in most mammals, lactase production declines after weaning. However, certain populations, such as Northern Europeans who traditionally consume large amounts of dairy, have a genetic mutation in the LCT gene that allows lactase to remain active into adulthood. Individuals without this genetic variant may experience gastrointestinal issues after consuming lactose-containing products (7).

Folate Metabolism

Folate is an essential vitamin that is important to DNA repair and synthesis. Additionally, it is critical to preventing neural tube defects during pregnancy. The MTHFR (methylenetetrahydrofolate reductase) gene is what codes for an enzyme important to folate metabolism.

One genetic variant known as C677T decreases this enzyme’s activity, causing increased homocysteine levels and decreased availability of folate. With this variant, pregnancy complications are higher, as well as cardiovascular disease and some types of cancer (8). Thus, people with this mutation can usually benefit from increasing their intake of folate-rich foods or supplementation with folate.

Omega-3 Fatty Acids

Omega-3 fatty acids are nutrients found in fish oils and certain plant sources. These can play a role in gene expression correlated with heart health and inflammation. In particular, fatty acids activate PPARs (peroxisome proliferator-activated receptors), which are transcription factors that control inflammation and lipid metabolism (9). Routine ingestion of omega-3s is associated with lower cardiovascular risk because of down-regulation of pro-inflammatory genes. Other genetic variations include FADS1 and FADS2 genes. These genes control for short chain versus long chain forms of omega-3s, and thus impact how individual bodies respond to omega-3s from diet (10).

The Potential for Personalized Nutrition and Disease Prevention

Personalized nutrition builds on some of the concepts we already mentioned. It considers someone’s genetic profile along with their microbiome, lifestyle, and metabolic biomarkers to tailor nutrition recommendations. Genomic information can be particularly helpful, as we can gain insights on how the individual responds to certain nutrients and dietary patterns. In doing so, we stray away from the traditional “one-size-fits-all” model of nutrition, leading to more effective interventions and better results.

Nutritional genomics can be particularly helpful when it comes to understanding and addressing disease risk. For example, people that have the APOE4 genetic variant tend to respond abnormally to dietary fats. As a result, these individuals are at increased risk of Alzheimer’s and cardiovascular disease. However, dietary modifications can help to decrease this risk (11). Another example is with the TCF7L2 gene. People with variations in this gene can be at higher risk of type 2 diabetes. As such, they may benefit from lower glycemic diets (12).

Thus, we can leverage personalized nutrition to mitigate disease risk by tailoring diet plans. In considering someone’s genetic makeup, personalized nutrition could potentially improve:

• Lipid profiles
• Blood sugar control
• Inflammation
• Nutrient absorption and utilization

In doing so, we can not only manage chronic conditions but also delay the start of disease. This is especially critical during early stages of development and life.

Limitations and Ethical Considerations

While this may all seem great, personalized nutrition and nutrigenomics does have some unique considerations and limitations. For starters, gene-nutrient interactions are not as cut-and-dry and we may believe. Health outcomes aren’t typically reliant on a single gene or nutrient. Instead, they involve complex interactions between several genes, environmental exposures, and metabolic processes. For example, while a certain genetic variant may be involved in folate processing, other factors like dietary patterns, microbiota composition, and other genes can all impact this process. Current scientific and medical models aren’t advanced enough to capture all of these nuances, potentially limiting the accuracy of genetic-based nutrition advice.

Additionally, note that gene expression is not solely controlled by the foods we eat. Other factors like exercise, sleep, stress, toxin exposure, and socioeconomic conditions can all impact our genetics. Therefore, we can’t oversimplify genetics by only considering nutrition. A more holistic approach will be most useful in implementing personalized nutrition strategies.

Another limitation relates to ethical and privacy concerns. Data breaches of sensitive health information can happen, which can compromise an individual’s willingness to share genetic information. Additionally, genetic testing and personalized nutrition can be costly, restricting access to many people.

Finally, while early studies surrounding nutrigenomics are promising, these results are still relatively preliminary. Further research will be required to substantiate these results and translate them into evidence-based recommendations. Many current studies were conducted in populations of European decent, which restricts the translatability to other populations. We’ll need to expand research to be inclusive of multi-ethnic and socioeconomically diverse populations to effectively understand nutrition-genetic frameworks.

Conclusion

The exciting potential of nutritional genomics cannot be understated. With recent research, we’ve realized that food can have an immense impact on how our bodies feel and function. Not only that, but we can use food as a tool to prevent and treat disease. While there is more to health than just food, we can add nutritional genomics to our toolbox to more effectively manage our health.

If you’re interested in learning more about the field of nutritional genomics, consider consulting with healthcare professionals or specialists seasoned in the field. In particular, those at Weight Loss and Vitality can offer personalized guidance and tailored nutritional plans. We invite you to take the next step toward personalized health and nutrition!

References

1. https://www.alisonbirks.com/the-science-of-nutrigenomics-and-nutrigenetics#:~:text=While%20nutrigenomics%20focuses%20on%20how,metabolize%20or%20utilize%20different%20nutrients.
2. https://study.com/academy/lesson/nutritional-genomics-nutrigenomics-nutrigenetics.html#:~:text=An%20example%20of%20nutrigenomics%20is,which%20can%20lead%20to%20cancer.
3. https://www.renuanutrition.com/blog/2023/7/11/what-is-nutrigenetics-and-how-is-it-beneficial#:~:text=What%20is%20an%20example%20of,recommendations%20based%20on%20genetic%20profiles.
4. https://www.nature.com/articles/nrg3142
5. https://www.sciencedirect.com/science/article/pii/S216183132200552X?via%3Dihub
6. https://www.tandfonline.com/doi/full/10.1128/MCB.23.15.5293-5300.2003
7. https://www.nature.com/articles/ng826z
8. https://www.sciencedirect.com/science/article/pii/S0022316623020126?via%3Dihub
9. https://journals.lww.com/co-lipidology/abstract/2002/04000/expression_profiling_and_comparative_sequence.9.aspx
10. https://www.sciencedirect.com/science/article/pii/S0002916523233079?via%3Dihub
11. https://pubmed.ncbi.nlm.nih.gov/17466101/
12. https://www.bmj.com/content/361/bmj.k2173

Author

David J. Bauder, PA-C David Bauder, PA-C, is a certified physician assistant and the assistant medical director at Weight Loss and Vitality in Manassas and Alexandria, Virginia, Washington, DC; and Gaithersburg, MD. He enjoys helping patients optimize their physical and mental health to improve their overall well-being. He earned his physician assistant degree from the University of Texas Health Science Center at San Antonio. Afterward, he gained admission into the reputable graduate program for physician assistant studies at the University of Nebraska Health Science Center in Omaha. David has over 26 years of experience working as a physician assistant. He’s practiced in podiatry, family medicine, emergency medicine, general surgery, urgent care, and functional medicine.