If some of us have friends who eat sweets every day and aren’t gaining weight, or relatives who developed heart disease despite avoiding saturated fats, the one-size-fits-all diet recommendation is for us. But now one of the most comprehensive and ambitious new studies on diet could change that, and experts are finally gives you insights that allow you to tailor your recommendations to different people.
Starting this spring, 13 sites across the United States will begin enrolling 10,000 people across ages and weights to better determine the key factors involved in what is called precision nutrition. Specific efforts will be made to include people who are often overlooked in nutritional science: those aged 65 and over, people of color, rural residents, people with disabilities, and sexual minorities.
During the first phase of the study, which lasts two weeks, everyone is instructed to eat normally. In the second phase, 1,500 people will be assigned one of several meals and the meals will be sent directly to their homes. And in the final phase, 500 people, selected from a larger group, will feed at the research center where he will stay for two weeks. The latter are the multitude of controlled nutrition studies that typically involve dozens of participants, says Holly Nicastro. Participants are selected from her NIH All of Us Health Research Program, which is open to anyone.
This large and diverse effort “will give us a step towards being able to provide more detailed nutritional recommendations to groups of individuals,” said one of the six research centers that coordinate the registry site. Sai Krupa Das, metabolic scientist at Tufts University,
How the survey works
During the study, researchers will regularly perform urine and blood tests to complete a survey of each person’s gut microbiome (the trillions of microbes that permanently reside in the digestive tract). Participants wear blood glucose monitors to record rises and falls in blood glucose levels. It is a marker of how well your body is processing carbohydrates and is an important indicator of your health. Daily activities such as sleep, stress and mealtimes are also tracked.
The new study will change our understanding of the human diet because it’s fundamentally different from how most nutrition research is conducted, said a member of the U.S. Military Academy at West Point, who was involved in the study. Diana Thomas, a professor of mathematics, says nutritional scientists typically look at single foods in homogeneous populations to see, for example, whether blueberries reduce the risk of cardiovascular disease in Americans ( The answer is still unknown). Instead of starting with a hypothesis, the study “asked what factors were involved,” she says.
The goal is to uncover the many variables that influence nutritional responses and develop algorithms to predict them so that nutritionists can provide dietary advice to others with similar characteristics.
Providing more targeted recommendations is key to improving public health, Das said. With the current approach, either because the advice seems to change frequently (classic: eggs are bad; eggs are good), or because you’ve tried the recommended eating habits and found that it’s not ideal. , many people are ignoring the dietary advice of the experts… for them. “Precision Nutrition will give you better results than the one-size-fits-all Mediterranean diet advice. “That’s the step we’re approaching,” she says.
Das warns that new advice derived from research does not reach the level of the individual. That is why experts prefer the term precision nutrition to another widely used term, personalized nutrition.
The research focuses on eating for optimal health, not for weight loss, but the two are closely related, Das says. Although we don’t offer it, we believe that our response in terms of trying to optimize our metabolism will also help with weight management.”
Gene vs Microbiome
Decades of research have already provided clues as to which factors shape overall health.
One of them is heredity. The field was formerly called nutrigenomics, but it fell out of favor when it became clear that genes played less of a role in how the body responded to food than first thought. Yes, says Jose Ordovas, director of nutrition and genomics at Tufts University.
In a small number of cases, scientists have linked specific genes to direct health effects. Genetic mutations determine whether a night cup of joe will make a person sleep through the night or allow for a restful night’s sleep. It also affects whether coffee helps with
“Genetics is involved, but there are so many other factors involved that we don’t have a predictive formula to individualize our recommendations,” Ordovás said. Many of these factors, especially behavior, are more easily modifiable than genes, so understanding them should lead to more effective approaches to improving health.
Hundreds of studies have shown that the microbiome (the bacteria, fungi, parasites and viruses that live in your gut) is a key factor in how your body processes food. For example, ingestion of artificial sweeteners alters the composition and function of the microbiome and increases glucose intolerance in healthy individuals. Certain gut microbes also persist in obese mice after dieting, tending to put them back on, and possibly us too.
There is still much to learn about the microbiome, including its optimal composition, how microbes work synergistically, and how lifestyle affects this community.
Influence of lifestyle on how food is processed
One of the most difficult aspects of finding the optimal diet for each individual is the complex interplay between genome, microbiome and lifestyle factors. The latter are what scientists call exposomes.
One of those lifestyle factors is when it’s time to eat dinner, says Elinav. His lab found that the gut microbiome follows a circadian rhythm, with microbiota composition predictably changing its numbers and functions over his 24-hour period. They do this by responding to signals from sleeping and eating behaviors.
“When shift work or jet lag disrupts sleep-wake patterns, one of the first things that happens is disruption of microbial diurnal activity,” says Elinav. Studies in mice suggest that the increased incidence of obesity, type 2 diabetes, and cancer associated with people whose sleep and eating schedules are chronically disrupted is due to this change in the microbiome. increase.
According to Das of Tufts, lack of sleep and intense stress further disrupt metabolism, which can negatively affect health even in those who eat a healthy diet.
NIH’s precision nutrition research will be the most comprehensive effort to use genes, microbiota, and exposomes to understand and predict nutritional responses to food, but it will not be the first. Several previous studies have paved the way.
One journaled effort led by Elinav’s lab cell In 2015, 800 people were fed the same diet and their blood sugar levels were continuously monitored. A week-long study revealed that participants’ glucose responses varied significantly from meal to meal. We noted that other factors were inevitably involved.
A few years later, a large-scale study was carried out in the UK to try to expand our knowledge of the variables at work. The study, called the Personalized Responses to Dietary Composition Trial (PREDICT), involved 1,000 adults, including genetically identical twins, to assess gut microbiota, blood fat, postprandial glucose levels, inflammation, and Other factors were monitored over 2 weeks. One of his co-authors, Ordovás of his Tufts, says tracking blood sugar levels throughout the day is also a key factor. Such continuous monitoring allowed researchers to measure the effects of specific foods.
Again, wide variation emerged indicating that the participants’ bodies were processing the same nutrients differently. We have shown how complex the system is. Prevotella copri and Blast cystis—was more important than genes for processing some foods, but both account for only a fraction of the overall difference.
The goal of future NIH research is to improve our understanding of the factors that explain these differences. It is hoped that this will allow people to adjust their lifestyle and diet, and possibly their gut microbiome, to improve the body’s response to different nutrients. It is not yet known whether manipulation of the will have lasting effects.)
For now, Das says the best nutrition advice she and others offer is sticking to the basics.Fill your plate with fiber-rich vegetables and fruits and avoid highly processed foods. Avoid and prefer natural foods.
“In the next five to 10 years, we’re going to see a big change in how we look at food,” predicts West Point’s Thomas. “We will know more as the NIH research results begin to emerge.”