(CNN) Is broccoli or beetroot the best option for your personal health? Which foods are likely to trigger the biggest glucose spikes or cholesterol surges in your blood?
Custom diets are the next frontier in nutrition science -- and artificial intelligence (AI) will play a key role in figuring out what each of us should, and shouldn't, be eating.
An ambitious program called Nutrition for Precision Health (NPH) kicked off in the US in January 2022 when the National Institutes of Health (NIH) awarded $170 million to fund institutions across the country to conduct a five-year study with 10,000 participants.
CNN spoke to Holly Nicastro, program director in the NIH office of nutrition research and coordinator of NPH, about the aims and scale of the project and how AI can benefit our health by helping to devise optimal diets for every individual.
This interview has been edited and condensed for clarity.
CNN: There's already a lot of information about healthy eating. Why is your approach different, and what's the goal?
Holly Nicastro: There is a lot of conflicting information, and there is no one-size-fits-all diet to stay healthy. The goal of NPH is to use AI to develop algorithms that predict individual responses to food and dietary patterns.
Our approach is different because we're looking at a comprehensive set of factors, many of which are not typically examined in nutrition science. The NPH study will examine how genes, the microbiome, biology and physiology, one's environment, lifestyle, health history, psychology, and social determinants of health impact individual responses to diet. Furthermore, we'll be studying one of the largest and most diverse cohorts of participants for a precision nutrition study.
CNN: Who are your participants?
Nicastro: Participants for NPH will be recruited from the All of Us Research Program, which is run by NIH. All of Us is inviting one million people across the US to help build one of the most diverse health databases in history. Most participants come from groups that have been previously underrepresented in the biomedical sciences. All of Us participants have provided information through surveys, electronic health records, biological samples, and digital health technologies like Fitbits. The diversity of the All of Us Research Program cohort will allow NPH to examine factors such as age, sex, race and ethnicity.
CNN: What data are you collecting, and how are you analyzing it?
Nicastro: NPH incorporates three modules. In Module 1, information on all the participants' normal day-to-day diets will be collected. In Module 2, a subset of Module 1 participants will eat three different diets selected by researchers. For Module 3, a smaller, and separate, subset of participants from Module 1 will participate in a two-week study in research centers where their food will be carefully controlled by researchers.
Each module will conclude with a meal challenge test. Participants will fast overnight and then consume a standardized breakfast meal or drink so that we can examine their responses, such as blood glucose levels, over several hours.
We'll be using mobile photography apps and wearable devices that can passively capture information on what people are eating. Participants will wear continuous glucose monitors and accelerometers which gather information about physical activity, sedentary time, and sleep. Researchers will also analyze various biomarkers -- like blood lipids and hormone levels -- and the stool microbiome.
The NPH study will link in data from the All of Us program and analyze it using AI. This approach creates an unprecedented opportunity to move nutrition research toward personalized nutrition because unlike human researchers, AI can sift through and process vast amounts of data quickly and translate connections between data points into algorithms. These can predict an individual's response to foods and dietary patterns, taking into account the role of genes, proteins, the microbiome, metabolism, and environmental and lifestyle factors.
CNN: Who stands to benefit the most from precision nutrition approaches?
Nicastro: Some of the earliest direct benefits could be for people at risk for diabetes or who have trouble regulating their blood glucose levels. Blood glucose monitors that attach to the skin allow us to learn how an individual's blood sugar will change after eating particular foods, food groups, or meals, and then predict those responses based on the individual's traits. This will help us develop tailored plans that prevent large blood sugar swings.
We're also using precision nutrition approaches to see how well we can predict other responses to diet, including changes in blood pressure, blood cholesterol or triglyceride levels, mood and cognition.
CNN: Are we really what we eat and how much could we improve our health through diet?
Nicastro: Poor diet is one of the leading causes of preventable disease and death around the world, and it is a huge driver of health care costs. Our diet affects our growth, development, risk and severity of disease, and overall wellbeing. Worldwide, almost 40% of adults have obesity or are overweight, over 30% have hypertension, and other diet-related chronic diseases are on the rise. Recent studies have indicated that about one in five deaths can be attributed to poor diet. Improving our diets has tremendous potential to change the health of the world.
If everyone followed population-wide guidance, like the Dietary Guidelines for Americans, we would expect to see improvements. These guidelines generally focus on including foods rich in nutrients and limiting added sugars, saturated fats, and sodium. However, this one-size-fits-most approach only gets us so far. We see some degree of individual variability in participants' responses in virtually all diet and nutrition intervention studies, and patients and consumers are increasingly seeking tailored approaches.
CNN: I'm convinced! When will custom dietary advice become widely available to the public?
Nicastro: Precision nutrition is already in practice. Clinical practitioners will provide different recommendations based on someone's disease profile, health history, or health and wellness goals. For example, recommendations for someone looking to control their diabetes will look very different from recommendations for someone who needs to increase their muscle mass.
Nutritional advice will become increasingly precise over the coming years. In the short term, more data points will be used to generate more tailored recommendations. Longer term, I hope to see the predictive factors identified by NPH being used during standard intake by health care professionals. This may involve having patients use new technologies like continuous glucose monitors or smart toilets that analyze the stool microbial composition in real time, or it may involve a simple genetic signature test.
For us to realize the full benefits of precision nutrition approaches, it will be essential to study and address barriers to following dietary recommendations. Precision approaches should focus on dietary recommendations that not only optimize someone's health, but also that are easy for an individual to follow based on their own resources, lifestyle, preferences, and abilities.