What Is It?
Precision nutrition may sound like a new fad diet, but it is actually a credible emerging area of research supported by the National Institutes of Health under the umbrella of precision medicine. [1,2] Precision medicine seeks to improve the personalized treatment of diseases, and precision nutrition is specific to dietary intake. Both develop interventions to prevent or treat chronic diseases based on a person’s unique characteristics like DNA, race, gender, health history, and lifestyle habits. Both aim to provide safer and more effective ways to prevent and treat disease by providing more accurate and targeted strategies. Precision nutrition assumes that each person may have a different response to specific foods and nutrients, so that the best diet for one individual may look very different than the best diet for another. How often are we tempted to follow a flashy diet that a celebrity or friend promoted in helping them to lose 20 pounds or “cure” their diabetes? The concept of precision nutrition would discourage this practice, as our individual blueprint might require a unique dietary plan to be successful.
Precision nutrition also considers the microbiome, trillions of bacteria in our bodies that play a key role in various daily internal operations. What types and how much bacteria we have are unique to each individual. Our diets can determine which types of bacteria live in our digestive tracts, and according to precision nutrition the reverse is also true: the types of bacteria we house might determine how we break down certain foods and what types of foods are most beneficial for our bodies.
How Does It Work?
Precision nutrition, also referred to as personalized nutrition, focuses on the individual rather than groups of people. Many research studies on nutrition and types of diets provide useful information for communities and the general population. High-quality nutrition studies have shown that for the average person, eating more vegetables, whole grains, and lean proteins while eating less highly processed foods made with added sugars and salt can help reduce the risk of various diseases. Yet, when studies such as the PREDICT 1 trial focus on individual responses to food, they have found substantial variations in blood responses of glucose and triglycerides even if individuals are eating identical meals.  The person’s microbiome was found to cause variations in blood triglycerides after a meal. Non-food factors like sleep, physical activity, and time of meals also played a role in causing variations in blood levels of glucose and triglycerides after meals.  Therefore, an individual may see additional benefits if following personalized nutrition guidance beyond general health recommendations. Precision nutrition evaluates one’s DNA, microbiome, and metabolic response to specific foods or dietary patterns to determine the most effective eating plan to prevent or treat disease.
Applying Precision Nutrition to Disease Management
There are specific dietary treatments based on genetic data that have been used for years: a gluten-free diet for the management of celiac disease, a lactose-free diet for those with lactose intolerance, and the avoidance of dietary phenylalanine (an amino acid in protein foods and some artificial sweeteners) for an inherited disorder called phenylketonuria (or PKU). However precision nutrition is in its early stages and too soon to introduce as a treatment for chronic diseases in the general population. Research is being conducted on the application of precision nutrition for obesity, metabolic syndrome, certain cancers, and type 2 diabetes (T2DM).
For example, the traditional management of T2DM targets healthy lifestyle factors (exercise, diet, achieving a healthy weight), often with use of medications. Precision nutrition can further tailor diabetes management by looking closely at the following areas: [4,5]
- How one’s DNA may be related to the intake and metabolism of certain nutrients, which can predict how a person responds to a specific diet.
- The measurement of metabolites (small molecules created during the breakdown and digestion of food) that reveal a person’s long-term dietary patterns, whether it be eating fruits and vegetables regularly or having a high intake of saturated fat from a daily intake of meats and butter. Precision nutrition would see if there is an association between a person’s metabolic “signature” created by these dietary patterns and their risk of developing T2DM. The metabolic testing used with precision nutrition might help to determine how a person’s body would respond to a specific diet.
- Discovering types of gut bacteria that help to improve blood glucose control, and implementing dietary patterns that change one’s microbiome to support the growth and maintenance of these specific gut bacteria.
Applying Precision Nutrition to Specific Foods
Precision nutrition examines how a person’s DNA may be associated with their response to a food. One example is coffee. Ever notice how some people are unfazed after drinking cup after cup of coffee during the day, while you may feel jittery and high-strung after only one cup? Coffee beans contain plant chemicals with health benefits but not everyone can tolerate the side effects from the caffeine content. Research has discovered genes specifically related to coffee intake.  These genes may determine how fast or slowly the caffeine in coffee is metabolized. They are also associated with anti-inflammatory effects and a lower risk of certain chronic diseases. Precision nutrition uses genetic data such as this to determine if an individual would benefit from drinking more or less coffee.
Other factors being researched include seeing if a high intake of saturated fat may predispose an individual to weight gain, or if a high salt intake increases one’s risk of developing high blood pressure.  However, findings from these studies have not been replicated in different populations.
The field of precision nutrition is not yet ready for prime time because of various challenges—a lack of well-designed clinical trials showing consistent results, and expensive technologies needed to collect and study an individual’s DNA, gut microbiome, and response to food intake.  Costly treatments such as these require high-quality evidence of their effectiveness and consistency before they may be recommended for use alongside or even to replace conventional interventions for a particular disease. There may also be differences among findings in clinical trials of the individual metabolic response to a specific diet depending on the types of tests they use; this in turn could cause variation in the personalized nutrition recommendations that are provided.
Primary care physicians, registered dietitians, and other providers directly interacting with an individual need to be educated about precision nutrition, as it requires the combined joint efforts of the entire health care team. Although private companies have started to offer genetic and microbiome testing to the public to customize diets based on an individual’s response to specific nutrients or foods, more research needs to be done on the effectiveness and accuracy of these tests. Ethical and legal aspects of implementing precision nutrition may also need to be considered.
- Precision Nutrition and Type 2 Diabetes Management: Is It Ready for Prime Time?
- Precision nutrition: Hype or hope?
Upcoming event: the role of teaching kitchens in precision nutrition research and practice
Hear from Frank Hu, MD, MPH, PhD, Fredrick J. Stare Professor of Nutrition and Epidemiology and Chair in the Department of Nutrition at the Harvard T.H. Chan School of Public Health, discuss the role of teaching kitchens in the emerging field of precision nutrition. The session is part of the virtual Teaching Kitchen Research Conference. Attendance is free but registration is required.
- Collins FS, Varmus H. A new initiative on precision medicine. New England journal of medicine. 2015 Feb 26;372(9):793-5.
- Rodgers GP, Collins FS. Precision nutrition—the answer to “what to eat to stay healthy”. JAMA. 2020 Aug 25;324(8):735-6.
- Berry SE, Valdes AM, Drew DA, Asnicar F, Mazidi M, Wolf J, Capdevila J, Hadjigeorgiou G, Davies R, Al Khatib H, Bonnett C. Human postprandial responses to food and potential for precision nutrition. Nature Medicine. 2020 Jun 11:1-0. Disclosure: TDS, SEB, AMV, FA, PWF, LMD and NS are consultants to Zoe Global Ltd (‘Zoe’). JW, GH, RD, HA., JC, CB, SG, EB, PW and IL are or have been employees of Zoe.
- Wang DD, Hu FB. Precision nutrition for prevention and management of type 2 diabetes. The lancet Diabetes & endocrinology. 2018 May 1;6(5):416-26. Disclosure: FBH reports personal fees from Metagenics and grants from California Walnut Commission, outside the submitted work.
- Zeevi D, Korem T, Zmora N, Israeli D, Rothschild D, Weinberger A, Ben-Yacov O, Lador D, Avnit-Sagi T, Lotan-Pompan M, Suez J. Personalized nutrition by prediction of glycemic responses. Cell. 2015 Nov 19;163(5):1079-94.
- Cornelis MC, Byrne EM, Esko T, Nalls MA, Ganna A, Paynter N, Monda KL, Amin N, Fischer K, Renstrom F, Ngwa JS. Genome-wide meta-analysis identifies six novel loci associated with habitual coffee consumption. Molecular psychiatry. 2015 May;20(5):647.
- Toro-Martín D, Arsenault BJ, Després JP, Vohl MC. Precision nutrition: a review of personalized nutritional approaches for the prevention and management of metabolic syndrome. Nutrients. 2017 Aug;9(8):913.
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