In our never-ending quest to be healthy, there is a constant and stubborn hope that we will find a hidden key to fitness – a tip or information that finally makes it easy to look and feel what we want.
That’s why weird diets take off and nutritional âbreakthroughsâ tend to go viral (though these findings rarely change what we know about healthy eating).
Recently, dieters and investors have started betting on companies offering “personalized nutrition”: dietetic advice supposedly based on our own genes or on the bacteria living in our intestines.
The talk of these companies goes like this: We are all unique and we know that our genes and bacterial populations have a huge impact on our health.
But there is reason to believe that modern science may not yet be up to the task.
The promise of personalized nutrition
“No two humans are the same and no diet is good for everyone,” says Naveen Jain, founder of a company called Viome, which monitors the microbiomes of its customers (specifically, their gut bacteria). and other biomarkers and uses this data to provide dietary advice. Viome charges its customers $ 99 per month (or $ 1,000 per year).
“We test you every 3 months to see how your body responds to carbohydrates, proteins and fats, and we adjust your diet based on what’s going on in your metabolic system.” Jain said.
Personalized or precision dietary advice, like precision medicine, is based on the realization that what works for one person doesn’t necessarily work for another – a shift in perspective that could transform the way we think about health. general. People with certain genetic variants thrive on high fat diets, while others are much more sensitive to the effects of consuming dietary cholesterol. This is the reason why so many companies are offering these dietary services based on DNA and now also on the microbiome.
But Ginger Hultin, a registered dietitian and nutritionist and spokesperson for the Academy of Nutrition and Dietetics, told Business Insider US that microbiome testing does not yet have proven practical applications.
“It’s too early,” she said. “Right now, the science is still current on dietary interventions to support the microbiome.”
Our gut bacteria influence our metabolism, immune system and other aspects of health, John Mathers, director of the Human Nutrition Research Center at Newcastle University, told Business Insider. But these complex interactions and relationships are not yet fully understood by health scientists.
“So far, we have limited evidence of how particular nutrients, foods, or eating habits influence the gut microbiota and very little evidence of how knowledge of the gut microbiome influences nutritional requirements,” he said. Mathers said.
According to Hultin, current scientific understanding of our gut suggests that the more diversity of bacteria, the better. And we know that a high fiber, plant-based diet is associated with a diverse gut flora. But this knowledge fundamentally supports the idea that vegetables are good for you – standard advice that any dietitian or nutritionist could provide. Beyond that, Hultin said, we don’t know enough to tell people how to eat based on their gut bacteria.
Business Insider asked Jain if he could provide evidence that Viome’s dietary advice (based on the microbiome and other metabolic biomarkers found in the gut and blood) improves health. He replied, “This is a question you should be asking in 6 months or a year.”
Jain also acknowledged that at this time, Viome cannot diagnose the disease based on his analyzes of customer microbiomes. Rather, the company is hoping that it will learn to do so as the technology advances.
Jain, however, provided Business Insider with a number of studies indicating that the microbiome is linked to a variety of chronic health conditions, ranging from obesity to Alzheimer’s disease.
âArticles show that every chronic disease – from Parkinson’s disease to asthma – is directly linked to the microbiome,â he says. “If you can balance your gut and eliminate chronic inflammationâ¦ if we can do it, we can create a world where no one will ever get sick.”
The problem, however, is that while Viome is successful in figuring out how to diagnose clients with certain conditions, no one has figured out how to cure diseases by changing the microbiome (except maybe giving people a fecal transplant. to fight off a Clostridium difficile infection). Were far to be able to “create a world where no one will ever get sick” based on treating the microbiome, however good that may sound.
“I don’t think we know enough about the microbiome to understand the importance of test results for dietary advice,” Marion NestlÃ©, professor of nutrition and public health at New York University, told Business Insider. .
Dieting Based on Your DNA
In addition to tailoring dietary advice based on the bacteria in your gut, there have been many companies that have offered DNA testing based dietary services for years, based on a science known as nutrigenomics.
âOur revolutionary DNA test will forever change your perception of fitness and nutrition,â reads the website of one such company, called DNAFit. “Whether you’re looking to get in shape, build muscle, or just eat a little healthier, your genetics hold valuable information on how best to do it, just for you.”
In some cases, a dietitian or genetic counselor may find useful information in a DNA test – certain genes may indicate basic intolerance to foods like lactose or caffeine, and genes common in obese people may help. explain why a person has trouble regulating their diet (although for the most part, genetic explanations for conditions such as obesity are complex and poorly understood).
But this type of genetic information is most likely to be useful in specific cases involving some sort of unsolved food sensitivity mystery, a rare occurrence because most people are already aware that they react badly to certain foods.
Hultin says that so far nutrigenomics “is actually more advanced [than microbiome research] and there are some really interesting things going on there. “
But NestlÃ© is skeptical.
“I guess DNA testing might reveal evidence of inborn metabolic errors” that make it difficult for people to process certain foods, she says, “but most adults with them have figured out what they need to do to avoid it. symptoms.”
An Academy of Nutrition and Dietetics position paper agrees: “The use of nutrigenetic tests to provide dietary advice is not ready for routine dietary practice,” he says.
Are any of these services worth the money?
So, is a DNA test or microbiome scan worth it to help you eat healthier? So far, most experts seem to think the answer is not yet.
Several reviews of existing research have found no evidence that genetic information, including data collected by several existing companies, improves dietary health. In other words, even though there is useful information hidden in our DNA, we haven’t learned enough about genetics to use the information successfully.
“I am skeptical of many of these products because of their thin – or non-existent – scientific basis,” John Mathers told Vox.
Hultin also points out that there are a lot of things people can try to test or change before they fork out for any of these diet services.
âIs there a job to do with your diet, your lifestyle, your stress or your sleep? she asks. Genetic testing is probably only helpful once you’ve resolved the obvious issues and obtained professional advice, she says. And even then, any information you get is probably best put into context by a medical professional.
Mathers cautions consumers to beware of the initial excitement that typically surrounds new food trends.
“In my opinion, there has been a lot of hype about the links between the microbiome and health and, based on current evidence, the idea that knowledge of our microbiome can be used to tell us what we should. eating is part of this hype, âhe says.
This doesn’t mean that personalized nutrition services can’t offer helpful guidelines. Many companies that offer these products combine the results of their tests with the advice of a nutritionist or other professional. Plus, most of their advice tends to be âeat more veggies,â which is a good suggestion for most people, even though they charge a lot for these tips.
At the very least, it could be fun to learn what’s in your DNA or microbiome, even if those are expensive ways to get that information. But don’t expect them to solve a dietary health mystery.
“The tests are fun, but their usefulness has yet to be demonstrated,” says NestlÃ©. âI prefer to spend the money on good dinners.