When we start reading an article titled “personalised nutrition”, we can probably already guess where it is heading. We expect to read about the importance of tailoring our diet not only to maintain good health, but also to achieve specific goals such as weight gain or weight loss. However, this article is not about that, because this is something most of us have already internalised, and it would hardly qualify as a nutrition trend in 2024. Personalised nutrition is not a new concept limited to simply assessing weight and height in order to design dietary plans. Since the emergence of nutritional genomics in 2003, encompassing disciplines such as nutrigenetics and nutrigenomics, following the full sequencing of the human genome in the Human Genome Project, the field has evolved significantly.
This article focuses on advances in how we personalise our diets. Thanks to nutritional genomics and its growing understanding among the general population, we have become much more aware of interindividual variability, the idea that each person is unique and should be treated as such. It is important to note that this variability is not determined solely by our genetics, but also by our habits. Nutritional genomics was a first step in helping us understand that we are different, but we now know that we differ for many reasons beyond genetics alone.
Next, we will explore new approaches that allow us to achieve an even greater degree of personalisation in our nutrition.
The gut microbiota: a new frontier in personalisation
Although the existence of the microbiota and the roles it plays in our bodies have been known for decades, it is only in recent years, with advances in genetic sequencing technologies and the reduction in their costs, that its involvement in different areas has been explored in greater depth. This has given rise to concepts such as the gut–brain–skin axis, and even to references to the gut as our “second brain”.
The gut microbiota, composed of trillions of microorganisms, influences how we respond to foods, how we absorb and digest them, and how we obtain their beneficial compounds, such as short-chain fatty acids.
Our diet has a direct impact on our microbiota. For example, a fibre-rich diet promotes the growth of beneficial bacteria that produce short-chain fatty acids such as butyrate, acetate and propionate, which are essential for gut and metabolic health. In contrast, a diet high in fats and refined sugars can encourage the growth of pathogenic bacteria and reduce microbial diversity, a pattern associated with an increased risk of metabolic diseases. In addition to diet, other factors such as lifestyle also influence the microbiota. Regular physical activity modulates the gut microbiota by stimulating bacteria that are beneficial to our bodies. Studies have shown that elite athletes have greater microbial diversity compared with sedentary individuals.
Symbiosis with the microbiota is crucial for maintaining balance within the body. Bacteria such as Bifidobacterium and Lactobacillus help digest nutrients and produce B-group vitamins and vitamin K, as well as antimicrobial compounds that protect us from infections. When this balance is disrupted, conditions such as irritable bowel syndrome, inflammatory bowel disease or metabolic disorders may arise, and these often require personalised treatment.
Understanding the composition and function of our gut microbiota can be highly valuable when making dietary choices. It not only allows us to adjust our diet to improve gut and metabolic health, but also offers a holistic view of how our eating and lifestyle habits interact with our unique biology. Although this field is still in its early stages, such knowledge will enable the design of more precise and effective nutritional strategies, thereby improving overall wellbeing and physical performance in a more individualised way.
Continuous glucose monitors: real-time personalisation
Technological advances have driven the development of continuous glucose monitors (CGMs), devices that track interstitial glucose levels in real time, which closely reflect blood glucose with slight variations. Initially designed for people with diabetes to prevent hypo- or hyperglycaemia, these devices are now being adopted by athletes and healthy individuals. They make it possible to understand how different foods affect blood glucose levels, enabling more precise dietary adjustments to optimise wellbeing and physical performance.
However, there are limitations. The glycaemic response to a given food does not depend solely on the food itself, but also on factors such as how it is combined with other foods and the individual’s stress levels. Beyond the glucose peak, it is also crucial to observe how quickly glucose levels fall in order to make informed dietary decisions. Although CGMs are gaining popularity among endurance and ultra-endurance athletes, where maintaining energy levels is critical, accurate interpretation of the data remains a challenge.
These devices generate large volumes of data that can be complex for users to interpret, potentially leading to suboptimal decisions if the information is not properly understood. While glucose monitors are clearly here to stay, further research and education are still needed before their widespread use among the healthy population can be fully recommended.
Metabolomics: decoding biochemical interactions
Metabolomics is an emerging scientific field that analyses the full set of metabolites present in an organism. These metabolites are small molecules involved in the biochemical reactions that sustain our cells and tissues. By studying an individual’s metabolomic profile, we can gain a detailed picture of their health status and how their body responds to different foods. This approach makes it possible to personalise nutrition at a deeper level, tailoring dietary recommendations not only according to genetics and the microbiota, but also to the individual’s specific biochemical interactions.
Metabolomics provides critical data on how certain foods can enhance athletic performance, prevent disease or improve overall wellbeing. This knowledge enables healthcare professionals to design nutritional plans that optimise metabolic function and promote optimal health.
Blood biomarkers: the key to precise personalised nutrition
Monitoring blood biomarkers is another powerful tool in personalised nutrition. These biomarkers include parameters such as glucose levels, cholesterol, vitamins, minerals and inflammatory markers, among others. By tracking these biomarkers, we can gain accurate insights into an individual’s health status and how different dietary interventions affect their body.
Advances in blood analysis technologies have made these tests more accessible and less invasive. With the information obtained, healthcare professionals can continuously and precisely adjust dietary recommendations, ensuring that nutritional interventions are effective and tailored to each person’s unique needs.
Applications and digital tools: enabling personalisation
We cannot conclude this article without mentioning digitalisation, which is transforming the personalisation of our health. Innovative tools such as Foodvisor allow users to obtain the nutritional profile and calorie count of a meal simply by taking a photo, although they still have notable limitations. For example, how can one distinguish between a low-fat yoghurt and a sweetened one based on an image alone? Despite this, such tools show promise for assessing and adjusting nutritional plans in the future without the need to weigh foods.
In addition, health applications, such as the Made of Genes app, are moving towards a more personalised approach. This app provides instant access to genetic analysis results, blood biomarkers and lifestyle data, allowing users to track how this information evolves over time. As we have seen throughout this article, focusing exclusively on nutritional genomics falls short. For this reason, a multimodal approach to health is essential and has proven effective in optimising personalised wellbeing.
Bibliography:
Defagó MD, Eynard AR. Potenciales de la nutrigenética en el abordaje y tratamiento de enfermedades cardiovasculares y factores de riesgo asociados [Nutrigenetics: potentials and applications in cardiovascular diseases and associated risk factors]. Rev Fac Cien Med Univ Nac Cordoba. 2022;79(2):168-180. Published 2022 Jun 6. doi:10.31053/1853.0605.v79.n2.30289
Rinninella E, Raoul P, Cintoni M, et al. What is the Healthy Gut Microbiota Composition? A Changing Ecosystem across Age, Environment, Diet, and Diseases. Microorganisms. 2019;7(1):14. Published 2019 Jan 10. doi:10.3390/microorganisms7010014
Flint HJ, Scott KP, Louis P, Duncan SH. The role of the gut microbiota in nutrition and health. Nat Rev Gastroenterol Hepatol. 2012;9(10):577-589. Published 2012 Sep 4. doi:10.1038/nrgastro.2012.156
Clarke SF, Murphy EF, O’Sullivan O, et al. Exercise and associated dietary extremes impact on gut microbial diversity. Gut. 2014;63(12):1913-1920. doi:10.1136/gutjnl-2013-306541
Flockhart, M., Larsen, F.J. Continuous Glucose Monitoring in Endurance Athletes: Interpretation and Relevance of Measurements for Improving Performance and Health. Sports Med 54, 247–255 (2024). https://doi.org/10.1007/s40279-023-01910-4
Lukács A, Szerencsi LB, Barkai L. Continuous glucose monitoring (CGM) satisfaction and its effect on mental health and glycemic control in adults with type 1 diabetes. Physiol Int. 2022;109(4):501-510. Published 2022 Nov 21. doi:10.1556/2060.2022.00125
Joshi S, Verma R, Lathia T, et al. Fitterfly Diabetes CGM Digital Therapeutics Program for Glycemic Control and Weight Management in People With Type 2 Diabetes Mellitus: Real-world Effectiveness Evaluation. JMIR Diabetes. 2023;8:e43292. Published 2023 May 3. doi:10.2196/43292
Hengist A, Ong JA, McNeel K, Guo J, Hall KD. Imprecision nutrition? Duplicate meals result in unreliable individual glycemic responses measured by continuous glucose monitors across four dietary patterns in adults without diabetes. Preprint. medRxiv. 2023;2023.06.14.23291406. Published 2023 Dec 11. doi:10.1101/2023.06.14.23291406
Shibutami E, Takebayashi T. A Scoping Review of the Application of Metabolomics in Nutrition Research: The Literature Survey 2000-2019. Nutrients. 2021;13(11):3760. Published 2021 Oct 24. doi:10.3390/nu13113760
Rodas G, Ferrer E, Reche X, Sanjuan-Herráez JD, McCall A, Quintás G. A targeted metabolic analysis of football players and its association to player load: Comparison between women and men profiles. Front Physiol. 2022;13:923608. Published 2022 Sep 30. doi:10.3389/fphys.2022.923608
Picó C, Serra F, Rodríguez AM, Keijer J, Palou A. Biomarkers of Nutrition and Health: New Tools for New Approaches. Nutrients. 2019;11(5):1092. Published 2019 May 16. doi:10.3390/nu11051092
