The concept of personalized nutrition is widely acknowledged as the future of nutritional approaches. However, it is not uncommon to hear the counterargument that personalized nutrition has already been practiced for many years. Both perspectives hold some truth, as different levels of personalized nutrition exist.
Three Distinct Tiers
Researchers, including Ronteltap and colleagues, have categorized personalized nutrition into three tiers.
The first tier represents the traditional approach of tailored advice from a dietitian, which takes into account an individual's dietary intake. Through a dietary assessment, specific recommendations for improvement are provided based on that person's unique circumstances.
The second tier of personalized nutrition expands beyond diet and incorporates phenotypic markers such as anthropometric measurements and blood biochemical markers. For instance, measuring iron levels or vitamin D status enables modifications to the diet or supplementation recommendations if deficiencies are identified.
The third and highest level combines the previous tiers with genotypical information. However, access to professional services that provide genotypical information is not as readily available. Interestingly, mainstream discussions on personalized nutrition often overlook the first two levels and primarily focus on direct-to-consumer (DTC) test kits that offer genotypical information.
The Rise of Genotype-Based Tests
Several companies now target consumers, promoting genotype testing and subsequent dietary adjustments. Although this idea seems enticing, the efficacy of such tests remains a topic of debate.
Assessing the Value of Genotype-Based Personalization
The crucial question that arises is whether personalized nutrition based on genotype leads to better, more sustainable, and cost-effective behavioral changes compared to conventional dietary advice. Does personalized nutrition driven by genotype contribute to improved health and performance among athletes? While personalized nutrition addressing factors like iron deficiency prevention, gastrointestinal problem avoidance, and glycogen resynthesis optimization may enhance exercise performance, the added value of genotype-based personalization is uncertain. To determine its significance, we need answers to several pivotal questions:
- Do athletes exhibit a higher likelihood of behavior change when presented with genotype-based advice?
- Is there sufficient evidence to support genotype-based dietary advice?
- Do athletes experience greater benefits from genotype-based advice compared to other forms of personalized nutrition?
Currently, limited evidence connects genotypical information to nutrition and performance. Furthermore, there is no indication that receiving genotype-based information leads to behavior change or greater performance improvements.
Challenges of Reliability
The challenges surrounding genotype-based personalization are exemplified by a straightforward example. A simple internet search reveals numerous instances where individuals have submitted their saliva samples with identical genetic information to various DTC companies for genotyping. These companies then provide reports with personalized recommendations. If this approach were reliable, one would expect consistency among the reports. Regrettably, this is not the case. Analysis methods and resulting recommendations vary significantly across different companies, even when evaluating the same sample. Consistency is lacking both in the interpretation of results and the subsequent advice. More extensive research is imperative to establish connections between specific genes, nutrition, health, and performance.
While personalized nutrition holds great importance, genotyping currently has no place in nutritional advice. Personalized nutrition based on genotype is not yet prepared for mainstream adoption, and it will require considerable time before it reaches that stage. In the realm of sports, where performance is the primary concern rather than health, research is even scarcer, thus extending the timeline further. For now, personalized sports nutrition entails clearly defining an athlete's goals and tailoring advice accordingly to meet those objectives and their specific training requirements.
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- Ronteltap, A., van Trijp, H., Berezowska, A., & Goossens, J. (2013). Nutrigenomics-based personalised nutritional advice: in search of a business model? Genes Nutr, 8(2), 153-163. doi:10.1007/s12263-012-0308-4
- O'Donovan, C. B., Walsh, M. C., Gibney, M. J., Gibney, E. R., & Brennan, L. (2016). Can metabotyping help deliver the promise of personalised nutrition? Proc Nutr Soc, 75(1), 106-114. doi:10.1017/S0029665115002347